It is a virtue to be able to come back and correct your mistake. Your two videos are the best takes and probably the only analysis of this product on YT.
@@glennoc8585 So making a huge mistake in his interpretation and still leaving the video online is ok? If it's embedded (and that's what people do in forums) you can't even see the first comment where he clarifies things). People are sharing his misinterpretations all over the internet and believe that crap.
This was needed. Love to see it, not enough of this on the internet or in the world. Integrity is key and that's why this channel will grow beyond the other media outlets that just churn out content without a thought.
Here's the thing. Accidents aren't covered by manufacturers warranty. So if the Frame is ruined you'll have to buy a new Frame so it's a win win for the Cycle manufacturers 🤔
Nicely explained. :) When I saw the "new, revolutionary design," one of my main concerns was the impacts - with hangers being softer for a reason, and now SRAM advertising their system as if getting rid of that is a benefit. As it is often the case in the (cycling) industry - marketing seems to be given more budget than engineering. My concern regarding the "35 Nm bolt periodic re-tightening" is that it might go deeper and deeper over time, perhaps increasing the amount of damage to a carbon dropout. Not that I have a better idea of how to deal with the preload losses due to the washer digging into the material over time. :( P.S. Only those who never do any work can never make any mistakes. Keep it up! :)
Parts of the mech will break before the dropout. You don't need to buy a full mech, just the part that breaks. Watch the fanatik bike destruction test.
the problem with people is that they think they gonna hot their rear mech that violently. they never thought of when was the last time they got their rear mech banged. and was it that strong that it can break this new mech? as if people can ride daily and crash daily. if you do crash daily might as well spend your money on this and enjoy,it will be inevitable that you'll be gone to a place where you cannot bring your money and gold.
@@miyui9269 you don't have to crash, lotta rock strikes ... But to your point, it's a lot more common for DH riders or crashing at the bike park. And 99% of guys who ride park aren't getting AXS or spending much on a drivetrain anyway, so I do see your point.
It seems kind of strange too, because I don't see why they couldn't have still used the same anti-rotation feature of that stop/nub on the dropout. Maybe a tiny weight savings.
thanks for the update...always good to have an honest exploration and discussion on anything new - especially the difference between thinking, drawing, making and testing
Thank you! As an mech engineer working in IT for 15 years I really enjoy your technical sound videos, destroying the marketing bs with simple (enough) facts.
One thing I always find fitting to say is that a few decades ago the drivetrain system on the bikes have developed so well that it has become so hard to make a modification to this system without either making it worse or less efficient.
The old design was about trying to save an expensive part by sacrificing a cheap part. The new design or complete removal of the sacrificial component has introduced other potentially more expensive problems. Perhaps the old system was too compliant rendering derailleurs out of alignment at the slightest of knocks.
The axle passes energy into the frame all the time from the wheel. Every time the wheel takes a big hit it is transferring all that energy into the frame. I don't think the derailleur mounting will significantly add to that.
@@imrevadasz1086 there is some give in a wheel but it also impacting the axle and dropouts constantly while riding. Every root, rock, case, drop etc. A derailleur in comparison very rarely makes contact with anything, and if it did there are still mechanisms to reduce the transfer of energy into the axle. Hangers are a design that predates mountain bikes entirely so they were not actually even designed with mountain biking in mind.
I think friction between the washer and the mech is actually supposed to be minimal, as that's the new B pivot point. The nub in the mech slots between the two horns in the knurled washer and there's constant spring tension pulling it against the chain tension depending on which cog you're in. It's apparent in the installation video that the washer position is set at installation time based on chain length at the setup cog with the cage locked at a known angle. That only leaves the issue of impact rotating the mech-washer assy which will definitely eat into the dropout.
@Peak Torque it is so easy to get caught up in the hype of a new, innovative product. I appreciate your skepticism, professional analysis, and integrity. I hope SRAM watches your videos and offers you a loner for a more hands-on review and possibly a torture test?
Good to see the elefant taken away from the room) However, we the viewers have something to add as well... Regarding impact - if it is in upper link directly, it is eqivalent to hitting the chainstay. If it is lower, it will be dampened by the parallelogramm and then distributed between chainstay and - yes - axle, partially dissipating in non drive side chainstay. Another case of similar force application - side impact to the wheel. Given it happens much more often and the leverage because of wheel radius is much greater as well, it gives confidence impacts to the derailleur must not damage sufficintly designed and manufactured frame (and if they do, the frame would have been trashed from regular use anyway). Regarding impact again, the old design was not absorbing much energy anyway. Gotta calculate the exact number though. Also, for the dropout I'd move the datum A to the inner side to replicate production - dropout spacing is measured from there already. And again, axle to dropout perpindicularity is already required by the disc brake. What is changed here is dropout thickness tolerance. Sram took the freedom of designing and producing the threaded insert, but also made manufacturers free of ensuring tolerances of that insert, instead they are obliged to make a hole - an easier task. Axle pressing the dropout - well, what other designs don't do that? Be it TA with UDH1, other TA hangers or QR - the force and consequent creep is always there. Although agree, not so wise to make it affect one more element. Lastly, in addition to my previous idea of epoxying the washer I'd file off those prongs too and let the derailleur swivel. From overarticulation it will be kept by the chain anyway.
Does this addendum change your understanding of being unable to tweak the “mech hanger” for parallel alignment with the cassette /wheel? Separate point, some existing carbon dropouts get munched by putting the wheel in and out. I could go back and look at your slides but does this set up reduce that wheel insertion scouring from end cap to dropout? Great vids.
Glad you posted this cause I was questioning your first video's interpretation of the attachment. But, like you, I'm still not sold on the knurled friction bit for resisting rotation of the mech. I suppose the best argument would be that having an integrated stop on the dropout is just much of a gamble from a big enough hit. That being said, i just checked my 2023 Epic Evo with UDH and low-and-behold, no stop. So not sure what that mean if my rear mech gets wrenched all the way around...
I got caught up in the fever pitch of the marketing bomb that went off on CZcams and had 1 hour between the embargo lift and Love Island so it was a bit rushed. A full analysis will be done when i get one.
TRP just launched their new groupset, much more affordable. Very bad timing though, SRAM marketing machine makes it difficult to find anything about it. If the quality is good, who knows, maybe we'll have a decent player to keep Sram and Shimano on their toes.
@@SnappyWasHere Shimano was a cheap crap? well, at least those "cheap crap" have better build quality from Japan than SRAM claimed as "german engineering" The truth is, Shimano has been around for 100 years, and they have been competing with other giant such as Campagnolo.
SRAM replied to a comment on their YT about the washer damaging the frame - "It absolutely will not eat into the frame. It is not a floating washer." This system appears to be much better than a hanger. In a simplified way it is closer to a miniature crankset spindle and arm. It is different and needs a different way of thinking about it.
They should just make the mech hanger out of duct tape since it ain’t nothing a little duct tape can’t fix…. I appreciate you recanting something you said in your previous video actually. Very refreshing to see somebody updating what they’ve said without deleting their previous mistake
All seriousness, duct tape has fixed a ton of my components ... I enjoy looking at it, but there's no way I'd drop this kinda cash on a drivetrain. It's cool, but I could careless about AXS. The tech will trickle down soon enough (Santa Cruz hinted at it coming this summer on Instagram). And I'm not against spending money on nice things, it's just I don't value my drivetrain as much since I'm mostly riding bike parks anyway. Plus there's something kinda romantic about regular bikes. I love that it's an escape and I'm not bogged down with emails and text messages, so I wouldn't want to introduce charging or Bluetooth into what I consider being off the grid.
i had a problem with the UDH on a SCOR, the Plastic hanger broke and the Carbon frame was dameged too. So the mac swings over the frame and did some bad damage to it:(
You could make a little plate wich can be screw thru both the hanger hole, then it could be pinched in the axle hole or have an own special axle and fixed there also. On that way you get same or near same stiffness and holding it still also. It will fit all brans also....
Great exploration of possible flaws. That said as much as this seems like an amazing evolution I’m certain by this time next years we’ll be buzzing about another new system that will make this new system seem primitive as this is how it’s always goes in bike world
Thanks for the video. Do you think there could be a breaking torque value specced for the rotation of the mech. Same idea as not doing the pinch bolts on your stem or brake levers up to 11. You want them to move in a crash, but not in use. If they could state the intended torque threshold to move the mech, in a big impact, it moves and theoretically you can just reset it. Do away with the frame circular saw washer, and use some kind of torque limiter, like in their totally unnecessary jockey wheel.
Any downside to just replacing the knurled washer with a flat washer of identical thickness? I imagine at 35 Nm torque spec, it would still take quite an impact to get the RD to rotate relative to the dropout, and you alleviate the risk of damage to the carbon…
@@armadillitoAdding carbon paste would have the same issue as the serrated washer. Carbon is incredibly weak to abrasion, and adding grit to grease would increase friction, and act like a grinding paste if a component slips. I think the best way to deal with this issue is a metallic face at the dropout, replaceable or otherwise.
When clamping carbon i always prefer a sandblasted finish to actual knurling. But it probably can't achieve same grip. However hub manufacturers have almost all done away with knurled end caps. DT Swiss have a very fine sandblast then anodize giving a very high Mu with little/ zero dropout damage
Thanks for an update. I still curious if those tolerances are really important in the case of "electronic" derailleur. I assume it should autotune on the fly and essentially dismiss all those tolerances issues? (Still dont like marketing bullshit like magic wheel)
Yep. It has trimming. It also looks like you can replace the mounting bushing. Peak and all the other Monday morning “engineers” also forget the crazy huge tolerances in standard derailleurs. They also think a part that is meant to flex (derailleur hanger) is a good thing for shifting. In my opinion, the derailleur’s priority should be on shifting rather than surviving a mishap and the new SRAM T-Type derailleur does this
I nearly commented on the previous video. A straight hanger is obviously very important for a cable derailleur because if it’s misaligned the fixed cable pull will mean either one end or the other of shifting won’t be right - but for an electronic derailleur you can set each shift independently so a slight misalignment doesn’t feel as important as a consistent stiff position.
Axial position can be taken out by electronic adjustment, but angularity cannot. Current 12 speed derailleur requires careful alignment with the derailleur hanger alignment tool to shift right. I assume that when you bolt the axel on, the torque will pull the derailleur hanger tight against the wheel hub. That is how SRAM ensure the derailleur hanger is perfectly perpendicular to the wheel hub.
My issue with this is that it seems (to me at least) if there is a problem down the line SRAM will look at the frame manufacturers and the frame manufacturers will look at SRAM and the customer will be left with problems that no one will be interested in solving.
I have to ask what was wrong with the 'nubbin' rotation end stop in the UDH design. Why change that to this knurled washer? I wonder whether the washer slipping under large impacts is a feature not a bug? Better that than smashing the drop out - it's like a hanger but only useful for impacts from the front.
Won't the serrated washer sit against the dropout nub on an existing udh frame thus preventing it from rotating and fretting the frame ? Surely new frames will still have the nub so that a shimano mech can be fitted with a udh hanger ?
Zero tolerance stack up ... As an engineer I would have never thought I would see this sentence in my entire life. Marketing does a great job. Very mature of you to admit your misunderstanding of the mechanical design of the product. Personally I think this could be an improvement. My hangers bend quite often and I would. One small change to the washer and frame interface could make this a real great advantage. Would love to see a design where the washer has a positioning interface / notch, without the serrated face and a bike frame wich interact with that notch. Pretty simple, but it's a change to the UDH interface which is difficult for this industry.
I think once you have a unit to fit and test your concerns will be addressed. The Stub axle sorts out the alignment and the tolerance. It terms of the knock back and serrated washer, yes that could abrade the carbon surface but consider that there are other features that reduce the likelihood of this scenario. The low profile design, the overload clutch and the outer parallelogram link breakaway feature all work together to take the energy out of the impact. I'm not buying the visco elastic creep claim for the stub axle torque losening up. Firstly the clamping area is large and typically carbon components are generally very dimensionally stable within the elastic limit and the material isn't crushed. I've never had stem bolts, QR skewers don;t loosen up in carbon frames, not do seat post wedges if the fram e is left static for months. This is simply a non issue. Once you'veplayed with it lets chat here again because I'm looking forward to your assessment after you've fondled the kit
In reality i agree its probably fit and forget. But it wouldn't be me if i didn't look into the small details/giving people a break from the blanket bombing of marketing videos. I hope to get to try one asap if my hightower is UDH!
I HIGHLY doubt SRAM would knowingly release a product that eliminates the hanger and increases risk of damage to the frame. The blowback would significantly damage their brand and market share. I awaiting more feedback with bated breath, and Transmission has definitely jumped up on my list of things to potentially upgrade.
@@GiovaniUrrutia exactly this ... They'd destroy their reputation. We're talking German engineering in the works since 2019 when they developed the UDH. They have thought and testing every single thing and I'm sure part of their research included talking to frame manufacturers, who are obviously fine with it since it's being marketed so heavily. And we're talking high end here, so these "transmissions" are gonna start off by going on expensive builds ... Just imagine the backlash if a bunch of carbon frames started breaking cause if it.
@@PeakTorque ditto , I’m a details guy too and I look at the why, how could it done differently and what would I do based on the design objectives. When the patent drawings were revealed on bikerumor I had a look and had similar concerns and also had a look at my DownHill racing mates broken parts. Most of them break the derailleur off because of either forgetting to engage the clutch on their Shimano RD or they use a cheaper SRAM derailleur like a NX because they’re constantly side swiping rocks. In these cases often it’s the clutch at fault or the chain is too short for extra tension . On a long travel bike that’s bad and places a lot of stress on the derailleur hanger as the load applied into it is in multiple directions. All of this works the hanger material and we know aluminium can work harden and fail. This is just one sort of failure. Improve the torsional rigidity of the mounting of the derailleur and it eliminates a potential failure point. I’m not sold on direct frontal impacts to the derailleur because that object has to get through a lot before it gets to the mech. Even when the drive side crank is top dead centre an object from the front has to get past the crank , chainring, chain stay. The derailleur cage is vulnerable but this design should make it more robust to being grabbed by sticks , shrubs , snakes etc. I believe there is enough fail safes built in for these concerns to abate over time
@@GiovaniUrrutia I think the product is great and a significant improvement on the derailleur system. However it does not mean it doesn't come with drawbacks. In my opinion the upside are better than the downsides BUT in case of a crash something will give and somtime it'll be the rear triangle. Will this system break more triangle than the old one ? Probably, but certainly not by much. It will prevent many other issues. Sometime a crash with a hanger will destroy a triangle that would not have happened with this system and vice versa. For example people riding with a bent hanger that they did not see will send the derailleur in the spokes, killing derailleur wheel and triangle (have seen this happen multiple times). When riding a mtb people must understand failure will happen at some point. You can't have something light and efficient and bombproof.
one thing I'm not sure on. in terms of alignment issues between the derailleur and cassette, I can't tell if the clamping force of the axle would bend an out of alignment dropout enough so that it sits flush with the endcap (and consequently the cassette). If yes, that would solve alignment issues correct? Would carbon bend enough for that to happen? Not saying that's a good way to do it, but is that the thinking here from Sram? hope that makes sense, not an engineer. thanks for all the excellent vids.
Yeh, the axle load would always pull in a dropout to some extent. Grab open dropouts between your hand and squeeze. Most frames are easily flexible here. They don't always come in parallel though, so those tight tols on the drawing are kind of academic
You know they engineered a break piece on the Derailer? It’s replaceable they also put plastic bumpers to absorb shock that’s replaceable as well… Im a mechanic with 15 years experience this idea you have that derailuer hangers save frames from damage is absurd. Broken Derailer hangers jack up frames ALOT. This new system looks to be better in every conceivable way you’ll see
As far as I can tell, the design intent of the knurled washer was to achieve a set chain gap without a B-screw. I agree that it's not a great solution, and personally I'm betting that we'll see the return of the B-screw in future iterations of the hangerless mech. Also, the original UDH isn't sacrificial in the same way as a conventional hanger. It doesn't really bend. Instead of all of the energy of an impact going into bending the hanger, in the UDH design the energy is supposed to be taken up partly by the friction of rotating the hanger, with the rest of it either dissipating into the rear triangle or snapping the hanger. This is exactly the same concept that is being applied in the hangerless mech. The UDH has been out for a good couple of years now, so if this kind of design was causing more damage to frames, we'd probably know by now.
Good video I’m glad you clarified some things. It builds a lot of trust to post a video like this. Truth be told I was wondering how you inferred so much from pictures and didn’t give anyone the benefit of the doubt that they thought of those things. I think you and others get caught up a bit too much in countering marketing efforts. Which I get. The shills are insufferable and it’s easy to want to get in front of that marketing engine. stay objective and keep up the good work!
I do this for fun believe it or not! Thankfully that means i can what i want (within reason) which may ruffle feathers. Engineers critique designs. That's different from criticism. Please remember that.
@@PeakTorque for sure and I agree. That said criticisms coming from pictures maybe need to be a little less… confident. Personally I think your points are all valid and won’t be giving up mech hangars anytime soon, but I think you understand the point. As engineers we test on real objects not pictures. As the bike manufacturers should take your criticism with stride I hope you can take ours.
I think that serrated washer is MIM or sintered. I doubt they would use aluminum for the reasons you stated. It will be interesting to see how this whole thing plays out.
I've been trying to figure out how the cassette mapping works. The only information I can find is that it relys on derailleur firmware and cassette geometry. From the reviews that I have seen, the system will not shift immediatly when requested, but will wait until the ramp features on the cassette are alligned in the optimal position. How does the derailleur know when to shift? Is there some type of position sensor used (unlikely) or is it some sort of electrical power/torque sensing in the deraileur that somehow senses a change in torque due to specific cassette ramp or specific geometry/tooth features. Thanks, Brian.
What about the (non-existing) rotation perpendicular to the wheel, in case of a crash. I don't think the UDH or this systems are better than the old derailleur hanger. It's called fuse for a reason!
I'm an engineer so I can appreciate where you're coming from in some ways. However, in most ways I think you've been massively over critical of the design despite it having some really smart features. Firstly; the new design makes the mech theoretically concentric to the axle, cassette etc. I sure trust SRAM to better job of machining all those components than most frame and especially mech hanger companies. I won't miss the DAG for even half a second. Secondly; you moan about impact loads going into the frame. This is partly true but some of the forces are also transferred through the axle into the other side of the swingarm. So overall the load is shared across both sides of the frame, similar to landing a jump or drop a bit sideways. Sounds better than a mech hanger made of cheese getting fired into my back wheel. Finally; if stiffening up this whole assembly and essentially taking shifting precision to the next level isn't worth it then kill me now. p.s. Can you please use your sway to persuade SRAM (if you've not pissed them off too much) to buy Pinion? I'd love a dual micro-clutch wireless shifted gearbox on my bike.
In your opinion, is that washer with the rotation-stops even necessary? I mean it doesn't really matter how far the mech is rotated back in a crash, does it? And then you could replace it with some bushing or washer, that won't damage the frame.
This issue is such an edge case though, how often are people hitting their derailleur so hard it's pushing beyond the limits? A handful of times in the life of the frame? It's not going to do serious damage and can be accommodated by trim.
13:10 if you look close I think that bike had an alloy plate between the hanger and the actual carbon dropout. Many carbon bikes had some kind of alloy part there for the axle threats. In the other side normal think is a bushing/insert to spread the axle load. I think brands made things little different here and there,but a do not see that steel washer being a major fault. I do not love the idea of being so expensive but it could survive most of regular accidents in enduro/trail ridding or at least it is harder than a regular one. Nice video.
Yeah noticed the same thing. That frame is probably totally fine. Although newer frames seem to not want to use aluminum inserts any more, not sure if its just weight reasons or cost is higher too. The red frame looks like its carbon only.
Real life issue with the T type , hoping for solution / fix . The mech inner marking line and the inner friction ring become misaligned during rides . At the start of the ride the two mark lines are perfectly lined up , at the end of the ride the inner mech mark line is few mm lower than the gripping washer mark . The torque of the mech bolt is correct at 35 Nm . A replacement was provided by SRAM unfortunately the same thing is happening . It this normal ? The friction ring does not seem to move at all , only the mech rotates downward ever so slightly ...shifting , if affected is very seldom ...Appreciate any help !
My understanding is the tolerance between the mech and the cassette are not dependent on the frame thickness etc. because the thru axle attaches to the mech not the frame. I dont think the serrated washer creeping into the frame does anything to the relation between the cassette and the mech. However this is similar in the UDH, with the translational tolerances only worsened by the bolted connection between the UDH and derailer.
Thank you for the reflected analysis. Mapdec said the serrated washer would be the other way round - so it would eat the mech hanger part... Anyway I'm really curious to see where lateral forces would end up - as you said, the axle can't absorb anything. I'm actually not too worried about the carbon - in case of fullys i guess the shocks would have to absorb a ton (and therefore die really quickly, especially coil shocks...) and other then that: the wheels (as i guess they are the things that try to keep the bike from going sideways)... If this would have been a road bike derailleur I think I'd be way less concerned...
Doesn’t the overload clutch dissipate some amount of energy in the case of an impact? There are some CZcams videos out there testing the previous Eagle AXS and it really takes a big impact to bend the derailleur hanger. I have not seen an engineering analysis of the energy dissipation through the clutch but it might be significant. Of course the un-clutched arm of the derailleur can still be impacted but the bending moment might be small enough to not be a problem.
think about the physics of the axel reducing the movement of the derailleur moment arm as movement is generated by a impact , the load is transferred to and carried by the axel, and unless you actually flex the axel and generate movement by all the derailleur laterally/perpendicular to the axel and the thread engagement system bushing /thread capture bolt and bushing assembly that goes through the dropout. And the analysis of the viseo elastic is assuming that the bushing bolt (thread capture housing ) is bottomed out at 35 NM, which it is not, the 35NM does not bottom out the system internally, so movement inward by the serrated plate is taken up each and every torque application.
Does the thru-axle just slide through the inner 'hanger' and then screw into the 35NM 'bolt' that secures the outer 'hanger'? If so does that mean that the axle diameter (where it locates the inner 'hanger') is now more critical?
Okay lets just say this design is fine, what was wrong with the old sacrificial hanger system? To trigger a redesign to a direct fit system? As i can see, this will work fine as long as everything is made well. as a disc brake system (caliper mounts, rotor alignment). If the items aren't, you are stuffed, no remedy or adjustment can be made at the bike shop to correct it as is now the case. But as we have seen with disc brakes, if the hub housing or caliper mounting points are off, then you will have a nightmare trying to set the system up.
My bikes are mostly 12mm TA with two Hex screws fastening two pieces either dude of the carbon abutment. I still like the idea of the threaded drop albeit very little in the way of a drop on my fitting and the design is such that it's not really a sacrificial part either. I can see how some impact force would transmit through the frame compared to the old school derailleur hangars. The idea of a slip design using a wave washer to facilitate movement with vertical pacts would be a welcome addition on MTBs imo. Not so sure about this new design, its basis is trying to keep alignment that's a good thing
@Peak Torque isn’t there also a forward rotation concern in using the serrated washer to “fix “ the rear mech? Seems that washer also acts as the stop to locate the mech’s fwd rotation when the chain is tensioned and pedaling etc. There must be considerable load under hard acceleration and climbs that is not all absorbed by the drivetrain. Look how often pro racers snap their chains at race starts now in MTB and CX races. And that load (or a portion of it) being applied through that washer hundreds of times every ride maybe wears that dropout over time? Also MTB / gravel gets the bike dirty - cant speak for anyone else but I taake the rear wheel off a lot for washing and cleaning (or just changing wheels for terrain). That is more variable load and clamping action on a very small area……
A thread in a thread always makes me uncomfortable. If they are both right handed will you need 2 wrenches to loosen /tighten the axle ? Won’t snugging the axle loosen the derailleur?
@@brianbob7514 no, the mech is still held in place without the axle, I was wrong about the left hand thread though, the UDH is left hand but the mech clamp is right hand
We've all seen how well frame manufacturers can adhere to specification even when it is critical to function. Back to threaded bbs so soon, at least bike shops can face those bb shells when they mess it up lol
Love the integrity. And totally get that abt wanting to get it right. Loads of CZcamsr could learn from this. Loads of them never address errors in gernal not just mtb. So yeah still love the derailleur tho. But not gonna upgrade from. My eagle axs tbh
just on the matter of the tolerances SRAM specifies. There has to be some tolerances applied. This isn't the civil engineering industry where everything gets measured on a thumbsuck and a plan is made to make parts line up :), the mounting system has to work in a degree of tolerance build up. Bike Industry may not be Civil Eng but sometimes I wonder because often plans do need to be made to get things to join. That said, the Stub axle is designed to work within a degree of tolerance build up and looks like it can accommodate a few mm either way (based on bikes being raced since last year I've had the chance to take a close look at and the bits as presented. There has to be a degree of fit adjustability and there has to be a specification for bike frame manufacturers to target ( i say that seriously and tongue in cheek at the same time). So yes tolerance is important in any worthwhile Eng Std. What I stand by is the ability for the system to be aligned during set up by the thru axle because that is exactly a step in the installation. A knock on effect of the UDH std is that manufacturers will find it harder to move an outside of tolerance product out of the warehouse onto the shop floor because the parts won't line up and therefore less chance of the consumer being saddled with a lemon they have to Civil Eng to get working. But there is enough play in the installation to allow for correct alignment of parts quickly which is a step forward for the bike shop mechanic. Just a pity they won't be moving much at the current pricing or maybe I'm just poor :)
Great videos, I love being able to see the nitty-gritty details of bike design discussed like this. However, I'm not understanding your concern with transferring the load into the thru axle to then be transmitted into a carbon frame. This is the exact pathway every impact and load from the rear wheel (rocks, roots, jumps) is transferred to the dropouts. Sure a side impact to the derailleur won't benefit from being damped by the tire but the magnitude will almost never be at the same level as what it is already taking.
I would imagine that if the derailleur gets snagged on a rock or a tree stump whilst moving at any kind of speed, the forces going into the frame will be orders of magnitude higher than those generated by the wheels going over bumps.
All of those forces you mention are acting upon the strongest plane of the bicycle Rearward impact tears the dropout face. Side impact transmits more impact to frame Than a traditional hanger..
I will take a look. As you rightly say 'critiquing', i will reiterate for others - I am not criticising SRAM. I am critiquing a design. Every engineer with a passion for his/her field WILL have an opinion on a design, released or unreleased. That's what makes us tick. I'm not forcing anyone to watch this, but judging by friends and forums people are sick to the back balls of the unpalatable blanket bombing marketing videos. CZcams is an open platform.
Not sure how I feel about the viscoelastic creep commentary. It sounds theoretically correct, however I doubt SRAM would implement a component with such a failure mode. Surely, SRAM has accounted or has done cyclic testing on the serrated/knurled part and the assembly.
I think its weird how basically every bike channel on CZcams has been going hard on this product and only saying great things about it. SRAM had to have thrown a ton of money at this rollout. I think you're right that this is not the best idea. Thanks for your honest opinion!
Nice presentation. Tech ocd 😂. The system is what it is with all its benefits and problems which will be shown in future but that chain powerlock not beeing reusable after removing the chain makes me really wonder if Sram got all other things just right? I mean c'mon Sram, wtf?
okay, so think about it: German engineers actually wanted to make the tension wheel without holes, but it was too heavy... so they thought: "Hey, let's try this overfuckingengineering method. And It worked, so they just said: "Just leave it, it'll be a coolness factor". Try making jockey and pulley wheel not hollow, and check the difference
There is alot of support for the content you put out on this , personally I feel it was a little disrespectful to thd engineers/product designers (you're peers) calling much of it turd , embarrassing oversight etc when you hadn't used thd product or more important, you hadn't understood the design. Many people had pointed out on original video you're facts where not correct. We all mzkd mistakes granted but the content you put out was not sound or verified, it was you're opinion and that's allowed but how you rubbished the product or certain aspects was unfounded. If you had used the product , had it in you're hand , disassembled it put it back together then you could have put out you're findings. But to do so simply by looking at images from other sites and some diagram online didn't work out to well. It may be you're over view is somewhat correct down the line, but his it was presented in the present doest look great.
I came to this video because my friend had problems with this rear derailleur. The chain became loose in the middle of the ride(specialized epic S-works). Loosening the 35Nm Bolt using only Swat 8mm allen key was not possible for us. Me and two friends tried without success. Sram lost some points!!
I think it may be a relief channel for the bushing end. If the dropout width is slightly undersized, the bushing end can sit in that recess without affecting the overall clamping. Just an idea. Seems to be the same dia as the bushing.
@@PeakTorque Oh, thanks. I'm not an engineer but I always find it interesting to learn things from your field. That's why I like your videos. By the way, Sram does claim that the load goes directly to the through axle. I just watched a german video from "enjoyyourbike" channel interviewing the chief engineer where he makes the claim.
One key point highly relevant to weight-weanies (most of us!) Is this new mech weighs nearly DOUBLE a Shimano XT (786) mech at a tenth of the price. And bear in mind that is unsprung weight, the worse kind on any vehicle.
The serrated washer bump-stop is such a good point! I suspect the only reason they did not include a raised section to impact the frame stop would be for aesthetics? Personally if I was purchasing this derailleur I'd be inclined to saw part of the serrated washer off so the derailleur will just keep rotating far beyond 60 degrees. Usually those big impacts are happening in the smallest few cogs where there is plenty of excess chain, so I see no risk of snapping it
It is a virtue to be able to come back and correct your mistake. Your two videos are the best takes and probably the only analysis of this product on YT.
Virtue? He should delete the first video! THEN and only then this would be virtue.
You are tripping hard.
@@harzenduro oh c'mon now
@@glennoc8585 So making a huge mistake in his interpretation and still leaving the video online is ok? If it's embedded (and that's what people do in forums) you can't even see the first comment where he clarifies things). People are sharing his misinterpretations all over the internet and believe that crap.
@FanatikBikeCo should learn to do this as well.
This was needed. Love to see it, not enough of this on the internet or in the world. Integrity is key and that's why this channel will grow beyond the other media outlets that just churn out content without a thought.
Here's the thing. Accidents aren't covered by manufacturers warranty. So if the Frame is ruined you'll have to buy a new Frame so it's a win win for the Cycle manufacturers 🤔
Giant actually covers crashes for two years!
@@Silidons91 thats a really impressive warranty. Other manufacturers will just give you 50% off from crash or less.
@@Silidons91 Say that to my un-warrantied giant frames.....
Nicely explained. :)
When I saw the "new, revolutionary design," one of my main concerns was the impacts - with hangers being softer for a reason, and now SRAM advertising their system as if getting rid of that is a benefit.
As it is often the case in the (cycling) industry - marketing seems to be given more budget than engineering.
My concern regarding the "35 Nm bolt periodic re-tightening" is that it might go deeper and deeper over time, perhaps increasing the amount of damage to a carbon dropout.
Not that I have a better idea of how to deal with the preload losses due to the washer digging into the material over time. :(
P.S.
Only those who never do any work can never make any mistakes. Keep it up! :)
Parts of the mech will break before the dropout. You don't need to buy a full mech, just the part that breaks. Watch the fanatik bike destruction test.
the problem with people is that they think they gonna hot their rear mech that violently. they never thought of when was the last time they got their rear mech banged. and was it that strong that it can break this new mech? as if people can ride daily and crash daily. if you do crash daily might as well spend your money on this and enjoy,it will be inevitable that you'll be gone to a place where you cannot bring your money and gold.
@@miyui9269 you don't have to crash, lotta rock strikes ... But to your point, it's a lot more common for DH riders or crashing at the bike park. And 99% of guys who ride park aren't getting AXS or spending much on a drivetrain anyway, so I do see your point.
Hangers were developed back when there wasn't a 12mm axle to stiffen and strengthen the rear end.
@@CanonFirefly hangers were developed as a standard to mount a rear derailleur. it was developed way before mountain biking existed.
Excellent update video.
If you're correct, Sram went from the best anti-rotation technique to the worst.
It seems kind of strange too, because I don't see why they couldn't have still used the same anti-rotation feature of that stop/nub on the dropout. Maybe a tiny weight savings.
thanks for the update...always good to have an honest exploration and discussion on anything new - especially the difference between thinking, drawing, making and testing
Thank you! As an mech engineer working in IT for 15 years I really enjoy your technical sound videos, destroying the marketing bs with simple (enough) facts.
All your doubts will be answer by the tons of mtb guinea pigs that are making lines to buy one, cheers
Yep.
Yep, jusy received mine
@@miatomi not exactly a guinea pig when its already been tested extensively for over 5 years.
@@martijndekker1134 congrats 🎉
@@portland675 proof that consumers will believe anything
I appreciate the simplicity and pure functionality of the derailleur hanger more and more lol
One thing I always find fitting to say is that a few decades ago the drivetrain system on the bikes have developed so well that it has become so hard to make a modification to this system without either making it worse or less efficient.
The old design was about trying to save an expensive part by sacrificing a cheap part. The new design or complete removal of the sacrificial component has introduced other potentially more expensive problems. Perhaps the old system was too compliant rendering derailleurs out of alignment at the slightest of knocks.
Love this level of detail, engineering insight! well done!
Well done for the clarification. I completely agree with all your points.
The axle passes energy into the frame all the time from the wheel. Every time the wheel takes a big hit it is transferring all that energy into the frame. I don't think the derailleur mounting will significantly add to that.
Wheels and tires are quite elastic, whereas the derailleur body is very stiff, that's not a great comparison, I think.
@@imrevadasz1086 there is some give in a wheel but it also impacting the axle and dropouts constantly while riding. Every root, rock, case, drop etc.
A derailleur in comparison very rarely makes contact with anything, and if it did there are still mechanisms to reduce the transfer of energy into the axle.
Hangers are a design that predates mountain bikes entirely so they were not actually even designed with mountain biking in mind.
In fact it's probable that wheels tend to taco before the frame breaks, and tacoing needs a lot of force
I think friction between the washer and the mech is actually supposed to be minimal, as that's the new B pivot point. The nub in the mech slots between the two horns in the knurled washer and there's constant spring tension pulling it against the chain tension depending on which cog you're in. It's apparent in the installation video that the washer position is set at installation time based on chain length at the setup cog with the cage locked at a known angle. That only leaves the issue of impact rotating the mech-washer assy which will definitely eat into the dropout.
@Peak Torque it is so easy to get caught up in the hype of a new, innovative product. I appreciate your skepticism, professional analysis, and integrity. I hope SRAM watches your videos and offers you a loner for a more hands-on review and possibly a torture test?
czcams.com/video/i3QzPxdN1e4/video.html
Thanks for taking the time to make this video, as always nice and clear explanation.
Good to see the elefant taken away from the room) However, we the viewers have something to add as well...
Regarding impact - if it is in upper link directly, it is eqivalent to hitting the chainstay. If it is lower, it will be dampened by the parallelogramm and then distributed between chainstay and - yes - axle, partially dissipating in non drive side chainstay. Another case of similar force application - side impact to the wheel. Given it happens much more often and the leverage because of wheel radius is much greater as well, it gives confidence impacts to the derailleur must not damage sufficintly designed and manufactured frame (and if they do, the frame would have been trashed from regular use anyway).
Regarding impact again, the old design was not absorbing much energy anyway. Gotta calculate the exact number though.
Also, for the dropout I'd move the datum A to the inner side to replicate production - dropout spacing is measured from there already. And again, axle to dropout perpindicularity is already required by the disc brake. What is changed here is dropout thickness tolerance. Sram took the freedom of designing and producing the threaded insert, but also made manufacturers free of ensuring tolerances of that insert, instead they are obliged to make a hole - an easier task.
Axle pressing the dropout - well, what other designs don't do that? Be it TA with UDH1, other TA hangers or QR - the force and consequent creep is always there. Although agree, not so wise to make it affect one more element.
Lastly, in addition to my previous idea of epoxying the washer I'd file off those prongs too and let the derailleur swivel. From overarticulation it will be kept by the chain anyway.
RE side impacts. czcams.com/video/i3QzPxdN1e4/video.html
Thanks for the corrections. I appreciate the integrity.
Love what you are doing, keep going.
Does this addendum change your understanding of being unable to tweak the “mech hanger” for parallel alignment with the cassette /wheel? Separate point, some existing carbon dropouts get munched by putting the wheel in and out. I could go back and look at your slides but does this set up reduce that wheel insertion scouring from end cap to dropout? Great vids.
Glad you posted this cause I was questioning your first video's interpretation of the attachment. But, like you, I'm still not sold on the knurled friction bit for resisting rotation of the mech. I suppose the best argument would be that having an integrated stop on the dropout is just much of a gamble from a big enough hit. That being said, i just checked my 2023 Epic Evo with UDH and low-and-behold, no stop. So not sure what that mean if my rear mech gets wrenched all the way around...
I got caught up in the fever pitch of the marketing bomb that went off on CZcams and had 1 hour between the embargo lift and Love Island so it was a bit rushed. A full analysis will be done when i get one.
@@PeakTorque be honest now... all this was just a ploy to get them to send you one, wasn't it? 😏
No one can afford it anyway. Just make components available and at a decent price.
Greedy bustards
TRP just launched their new groupset, much more affordable. Very bad timing though, SRAM marketing machine makes it difficult to find anything about it.
If the quality is good, who knows, maybe we'll have a decent player to keep Sram and Shimano on their toes.
If you want cheap crap just buy shimano. This is the luxury car of bike parts, plenty of market for those who want the shiny parts.
@@SnappyWasHere your mean sram crap right?
@@SnappyWasHere Shimano was a cheap crap?
well, at least those "cheap crap" have better build quality from Japan than SRAM claimed as
"german engineering"
The truth is, Shimano has been around for 100 years, and they have been competing with other giant such as Campagnolo.
SRAM replied to a comment on their YT about the washer damaging the frame - "It absolutely will not eat into the frame. It is not a floating washer."
This system appears to be much better than a hanger. In a simplified way it is closer to a miniature crankset spindle and arm. It is different and needs a different way of thinking about it.
But of course they would say that. In reality everything fixed gets loosened and everything free floating gets stuck.
They should just make the mech hanger out of duct tape since it ain’t nothing a little duct tape can’t fix….
I appreciate you recanting something you said in your previous video actually. Very refreshing to see somebody updating what they’ve said without deleting their previous mistake
All seriousness, duct tape has fixed a ton of my components ... I enjoy looking at it, but there's no way I'd drop this kinda cash on a drivetrain. It's cool, but I could careless about AXS. The tech will trickle down soon enough (Santa Cruz hinted at it coming this summer on Instagram). And I'm not against spending money on nice things, it's just I don't value my drivetrain as much since I'm mostly riding bike parks anyway. Plus there's something kinda romantic about regular bikes. I love that it's an escape and I'm not bogged down with emails and text messages, so I wouldn't want to introduce charging or Bluetooth into what I consider being off the grid.
i do like this new sram system is pretty good. just wish they got a cable actuated one.
i had a problem with the UDH on a SCOR, the Plastic hanger broke and the Carbon frame was dameged too. So the mac swings over the frame and did some bad damage to it:(
You could make a little plate wich can be screw thru both the hanger hole, then it could be pinched in the axle hole or have an own special axle and fixed there also. On that way you get same or near same stiffness and holding it still also. It will fit all brans also....
Great exploration of possible flaws. That said as much as this seems like an amazing evolution I’m certain by this time next years we’ll be buzzing about another new system that will make this new system seem primitive as this is how it’s always goes in bike world
Thanks for the video. Do you think there could be a breaking torque value specced for the rotation of the mech. Same idea as not doing the pinch bolts on your stem or brake levers up to 11. You want them to move in a crash, but not in use. If they could state the intended torque threshold to move the mech, in a big impact, it moves and theoretically you can just reset it. Do away with the frame circular saw washer, and use some kind of torque limiter, like in their totally unnecessary jockey wheel.
Thank you for your efforts 🙏
Any downside to just replacing the knurled washer with a flat washer of identical thickness? I imagine at 35 Nm torque spec, it would still take quite an impact to get the RD to rotate relative to the dropout, and you alleviate the risk of damage to the carbon…
Knurled washer for alloys or a smooth one with grip paste for carbon?
@@armadillitoAdding carbon paste would have the same issue as the serrated washer. Carbon is incredibly weak to abrasion, and adding grit to grease would increase friction, and act like a grinding paste if a component slips. I think the best way to deal with this issue is a metallic face at the dropout, replaceable or otherwise.
When clamping carbon i always prefer a sandblasted finish to actual knurling. But it probably can't achieve same grip. However hub manufacturers have almost all done away with knurled end caps. DT Swiss have a very fine sandblast then anodize giving a very high Mu with little/ zero dropout damage
Thanks for an update. I still curious if those tolerances are really important in the case of "electronic" derailleur. I assume it should autotune on the fly and essentially dismiss all those tolerances issues? (Still dont like marketing bullshit like magic wheel)
Yep. It has trimming. It also looks like you can replace the mounting bushing.
Peak and all the other Monday morning “engineers” also forget the crazy huge tolerances in standard derailleurs. They also think a part that is meant to flex (derailleur hanger) is a good thing for shifting. In my opinion, the derailleur’s priority should be on shifting rather than surviving a mishap and the new SRAM T-Type derailleur does this
I nearly commented on the previous video. A straight hanger is obviously very important for a cable derailleur because if it’s misaligned the fixed cable pull will mean either one end or the other of shifting won’t be right - but for an electronic derailleur you can set each shift independently so a slight misalignment doesn’t feel as important as a consistent stiff position.
Axial position can be taken out by electronic adjustment, but angularity cannot. Current 12 speed derailleur requires careful alignment with the derailleur hanger alignment tool to shift right.
I assume that when you bolt the axel on, the torque will pull the derailleur hanger tight against the wheel hub. That is how SRAM ensure the derailleur hanger is perfectly perpendicular to the wheel hub.
Non engineer here. It'll probably be fine.
Excellent update..
Is it possible that a carbon dropout surface could be resurfaced with new carbon or even a thin metal plate? Would repair tolerances be tight enough?
My issue with this is that it seems (to me at least) if there is a problem down the line SRAM will look at the frame manufacturers and the frame manufacturers will look at SRAM and the customer will be left with problems that no one will be interested in solving.
Ok then, it still has a mech hanger but integrated. How they prevent it from bending or not beaking the frame?
Great video and follow-up.
I have to ask what was wrong with the 'nubbin' rotation end stop in the UDH design. Why change that to this knurled washer? I wonder whether the washer slipping under large impacts is a feature not a bug? Better that than smashing the drop out - it's like a hanger but only useful for impacts from the front.
Yeh possibly. What's the lesser of two evils. Not sure. In Alu, the nub would be better. In CF, not sure
What do you think of the Nivex rear derailleur design?
Won't the serrated washer sit against the dropout nub on an existing udh frame thus preventing it from rotating and fretting the frame ? Surely new frames will still have the nub so that a shimano mech can be fitted with a udh hanger ?
Zero tolerance stack up ... As an engineer I would have never thought I would see this sentence in my entire life.
Marketing does a great job.
Very mature of you to admit your misunderstanding of the mechanical design of the product.
Personally I think this could be an improvement. My hangers bend quite often and I would.
One small change to the washer and frame interface could make this a real great advantage. Would love to see a design where the washer has a positioning interface / notch, without the serrated face and a bike frame wich interact with that notch. Pretty simple, but it's a change to the UDH interface which is difficult for this industry.
I think once you have a unit to fit and test your concerns will be addressed. The Stub axle sorts out the alignment and the tolerance. It terms of the knock back and serrated washer, yes that could abrade the carbon surface but consider that there are other features that reduce the likelihood of this scenario. The low profile design, the overload clutch and the outer parallelogram link breakaway feature all work together to take the energy out of the impact. I'm not buying the visco elastic creep claim for the stub axle torque losening up. Firstly the clamping area is large and typically carbon components are generally very dimensionally stable within the elastic limit and the material isn't crushed. I've never had stem bolts, QR skewers don;t loosen up in carbon frames, not do seat post wedges if the fram e is left static for months. This is simply a non issue. Once you'veplayed with it lets chat here again because I'm looking forward to your assessment after you've fondled the kit
In reality i agree its probably fit and forget. But it wouldn't be me if i didn't look into the small details/giving people a break from the blanket bombing of marketing videos. I hope to get to try one asap if my hightower is UDH!
I HIGHLY doubt SRAM would knowingly release a product that eliminates the hanger and increases risk of damage to the frame. The blowback would significantly damage their brand and market share.
I awaiting more feedback with bated breath, and Transmission has definitely jumped up on my list of things to potentially upgrade.
@@GiovaniUrrutia exactly this ... They'd destroy their reputation. We're talking German engineering in the works since 2019 when they developed the UDH. They have thought and testing every single thing and I'm sure part of their research included talking to frame manufacturers, who are obviously fine with it since it's being marketed so heavily. And we're talking high end here, so these "transmissions" are gonna start off by going on expensive builds ... Just imagine the backlash if a bunch of carbon frames started breaking cause if it.
@@PeakTorque ditto , I’m a details guy too and I look at the why, how could it done differently and what would I do based on the design objectives. When the patent drawings were revealed on bikerumor I had a look and had similar concerns and also had a look at my DownHill racing mates broken parts. Most of them break the derailleur off because of either forgetting to engage the clutch on their Shimano RD or they use a cheaper SRAM derailleur like a NX because they’re constantly side swiping rocks. In these cases often it’s the clutch at fault or the chain is too short for extra tension . On a long travel bike that’s bad and places a lot of stress on the derailleur hanger as the load applied into it is in multiple directions. All of this works the hanger material and we know aluminium can work harden and fail. This is just one sort of failure. Improve the torsional rigidity of the mounting of the derailleur and it eliminates a potential failure point. I’m not sold on direct frontal impacts to the derailleur because that object has to get through a lot before it gets to the mech. Even when the drive side crank is top dead centre an object from the front has to get past the crank , chainring, chain stay. The derailleur cage is vulnerable but this design should make it more robust to being grabbed by sticks , shrubs , snakes etc. I believe there is enough fail safes built in for these concerns to abate over time
@@GiovaniUrrutia I think the product is great and a significant improvement on the derailleur system. However it does not mean it doesn't come with drawbacks. In my opinion the upside are better than the downsides BUT in case of a crash something will give and somtime it'll be the rear triangle. Will this system break more triangle than the old one ? Probably, but certainly not by much. It will prevent many other issues. Sometime a crash with a hanger will destroy a triangle that would not have happened with this system and vice versa. For example people riding with a bent hanger that they did not see will send the derailleur in the spokes, killing derailleur wheel and triangle (have seen this happen multiple times).
When riding a mtb people must understand failure will happen at some point. You can't have something light and efficient and bombproof.
I respect you even more, thank you!
one thing I'm not sure on. in terms of alignment issues between the derailleur and cassette, I can't tell if the clamping force of the axle would bend an out of alignment dropout enough so that it sits flush with the endcap (and consequently the cassette). If yes, that would solve alignment issues correct? Would carbon bend enough for that to happen? Not saying that's a good way to do it, but is that the thinking here from Sram?
hope that makes sense, not an engineer. thanks for all the excellent vids.
Yeh, the axle load would always pull in a dropout to some extent. Grab open dropouts between your hand and squeeze. Most frames are easily flexible here. They don't always come in parallel though, so those tight tols on the drawing are kind of academic
You know they engineered a break piece on the Derailer? It’s replaceable they also put plastic bumpers to absorb shock that’s replaceable as well…
Im a mechanic with 15 years experience this idea you have that derailuer hangers save frames from damage is absurd. Broken Derailer hangers jack up frames ALOT.
This new system looks to be better in every conceivable way you’ll see
As far as I can tell, the design intent of the knurled washer was to achieve a set chain gap without a B-screw. I agree that it's not a great solution, and personally I'm betting that we'll see the return of the B-screw in future iterations of the hangerless mech.
Also, the original UDH isn't sacrificial in the same way as a conventional hanger. It doesn't really bend. Instead of all of the energy of an impact going into bending the hanger, in the UDH design the energy is supposed to be taken up partly by the friction of rotating the hanger, with the rest of it either dissipating into the rear triangle or snapping the hanger. This is exactly the same concept that is being applied in the hangerless mech. The UDH has been out for a good couple of years now, so if this kind of design was causing more damage to frames, we'd probably know by now.
top job on putting an update out.
Good video I’m glad you clarified some things. It builds a lot of trust to post a video like this. Truth be told I was wondering how you inferred so much from pictures and didn’t give anyone the benefit of the doubt that they thought of those things. I think you and others get caught up a bit too much in countering marketing efforts. Which I get. The shills are insufferable and it’s easy to want to get in front of that marketing engine. stay objective and keep up the good work!
I do this for fun believe it or not! Thankfully that means i can what i want (within reason) which may ruffle feathers. Engineers critique designs. That's different from criticism. Please remember that.
@@PeakTorque for sure and I agree. That said criticisms coming from pictures maybe need to be a little less… confident. Personally I think your points are all valid and won’t be giving up mech hangars anytime soon, but I think you understand the point. As engineers we test on real objects not pictures. As the bike manufacturers should take your criticism with stride I hope you can take ours.
I think that serrated washer is MIM or sintered. I doubt they would use aluminum for the reasons you stated.
It will be interesting to see how this whole thing plays out.
I've been trying to figure out how the cassette mapping works. The only information I can find is that it relys on derailleur firmware and cassette geometry. From the reviews that I have seen, the system will not shift immediatly when requested, but will wait until the ramp features on the cassette are alligned in the optimal position. How does the derailleur know when to shift? Is there some type of position sensor used (unlikely) or is it some sort of electrical power/torque sensing in the deraileur that somehow senses a change in torque due to specific cassette ramp or specific geometry/tooth features. Thanks, Brian.
What about the (non-existing) rotation perpendicular to the wheel, in case of a crash. I don't think the UDH or this systems are better than the old derailleur hanger. It's called fuse for a reason!
I'm an engineer so I can appreciate where you're coming from in some ways. However, in most ways I think you've been massively over critical of the design despite it having some really smart features.
Firstly; the new design makes the mech theoretically concentric to the axle, cassette etc. I sure trust SRAM to better job of machining all those components than most frame and especially mech hanger companies. I won't miss the DAG for even half a second.
Secondly; you moan about impact loads going into the frame. This is partly true but some of the forces are also transferred through the axle into the other side of the swingarm. So overall the load is shared across both sides of the frame, similar to landing a jump or drop a bit sideways. Sounds better than a mech hanger made of cheese getting fired into my back wheel.
Finally; if stiffening up this whole assembly and essentially taking shifting precision to the next level isn't worth it then kill me now.
p.s. Can you please use your sway to persuade SRAM (if you've not pissed them off too much) to buy Pinion? I'd love a dual micro-clutch wireless shifted gearbox on my bike.
Hello. I got a question. I i would use narrow wide chainring not from SRAM, would t-type transmision thing still function well?
In your opinion, is that washer with the rotation-stops even necessary? I mean it doesn't really matter how far the mech is rotated back in a crash, does it? And then you could replace it with some bushing or washer, that won't damage the frame.
This issue is such an edge case though, how often are people hitting their derailleur so hard it's pushing beyond the limits? A handful of times in the life of the frame? It's not going to do serious damage and can be accommodated by trim.
13:10 if you look close I think that bike had an alloy plate between the hanger and the actual carbon dropout. Many carbon bikes had some kind of alloy part there for the axle threats. In the other side normal think is a bushing/insert to spread the axle load. I think brands made things little different here and there,but a do not see that steel washer being a major fault. I do not love the idea of being so expensive but it could survive most of regular accidents in enduro/trail ridding or at least it is harder than a regular one. Nice video.
Yeah noticed the same thing. That frame is probably totally fine. Although newer frames seem to not want to use aluminum inserts any more, not sure if its just weight reasons or cost is higher too.
The red frame looks like its carbon only.
@@jaro6985 totally agree
Real life issue with the T type , hoping for solution / fix . The mech inner marking line and the inner friction ring become misaligned during rides . At the start of the ride the two mark lines are perfectly lined up , at the end of the ride the inner mech mark line is few mm lower than the gripping washer mark . The torque of the mech bolt is correct at 35 Nm . A replacement was provided by SRAM unfortunately the same thing is happening . It this normal ? The friction ring does not seem to move at all , only the mech rotates downward ever so slightly ...shifting , if affected is very seldom ...Appreciate any help !
My understanding is the tolerance between the mech and the cassette are not dependent on the frame thickness etc. because the thru axle attaches to the mech not the frame. I dont think the serrated washer creeping into the frame does anything to the relation between the cassette and the mech. However this is similar in the UDH, with the translational tolerances only worsened by the bolted connection between the UDH and derailer.
Thank you for the reflected analysis. Mapdec said the serrated washer would be the other way round - so it would eat the mech hanger part... Anyway I'm really curious to see where lateral forces would end up - as you said, the axle can't absorb anything. I'm actually not too worried about the carbon - in case of fullys i guess the shocks would have to absorb a ton (and therefore die really quickly, especially coil shocks...) and other then that: the wheels (as i guess they are the things that try to keep the bike from going sideways)... If this would have been a road bike derailleur I think I'd be way less concerned...
Serrated washer goes against the frame side. Smooth side against the mech plate to allow the "knock-back" function in an impact.
Doesn’t the overload clutch dissipate some amount of energy in the case of an impact? There are some CZcams videos out there testing the previous Eagle AXS and it really takes a big impact to bend the derailleur hanger. I have not seen an engineering analysis of the energy dissipation through the clutch but it might be significant. Of course the un-clutched arm of the derailleur can still be impacted but the bending moment might be small enough to not be a problem.
oh crap, they got to him!
think about the physics of the axel reducing the movement of the derailleur moment arm as movement is generated by a impact , the load is transferred to and carried by the axel, and unless you actually flex the axel and generate movement by all the derailleur laterally/perpendicular to the axel and the thread engagement system bushing /thread capture bolt and bushing assembly that goes through the dropout. And the analysis of the viseo elastic is assuming that the bushing bolt (thread capture housing ) is bottomed out at 35 NM, which it is not, the 35NM does not bottom out the system internally, so movement inward by the serrated plate is taken up each and every torque application.
Does the thru-axle just slide through the inner 'hanger' and then screw into the 35NM 'bolt' that secures the outer 'hanger'?
If so does that mean that the axle diameter (where it locates the inner 'hanger') is now more critical?
Ah, just got to it on the vid :-)
Okay lets just say this design is fine, what was wrong with the old sacrificial hanger system? To trigger a redesign to a direct fit system?
As i can see, this will work fine as long as everything is made well. as a disc brake system (caliper mounts, rotor alignment). If the items aren't, you are stuffed, no remedy or adjustment can be made at the bike shop to correct it as is now the case. But as we have seen with disc brakes, if the hub housing or caliper mounting points are off, then you will have a nightmare trying to set the system up.
Another hammer looking for a nail.
Really appreciate this video and a small UK frame maker.
I know a guy who’s sponsored who’s been riding one for a while and he loves it and has had no issues with it and has sent the bike.
My bikes are mostly 12mm TA with two Hex screws fastening two pieces either dude of the carbon abutment. I still like the idea of the threaded drop albeit very little in the way of a drop on my fitting and the design is such that it's not really a sacrificial part either. I can see how some impact force would transmit through the frame compared to the old school derailleur hangars. The idea of a slip design using a wave washer to facilitate movement with vertical pacts would be a welcome addition on MTBs imo. Not so sure about this new design, its basis is trying to keep alignment that's a good thing
They like to talk about "zero tolerance" because it sounds nice.
Never mind all this SRAM stuff… the rider you’re following in the intro is pinned 😮
@Peak Torque isn’t there also a forward rotation concern in using the serrated washer to “fix “ the rear mech? Seems that washer also acts as the stop to locate the mech’s fwd rotation when the chain is tensioned and pedaling etc. There must be considerable load under hard acceleration and climbs that is not all absorbed by the drivetrain. Look how often pro racers snap their chains at race starts now in MTB and CX races. And that load (or a portion of it) being applied through that washer hundreds of times every ride maybe wears that dropout over time? Also MTB / gravel gets the bike dirty - cant speak for anyone else but I taake the rear wheel off a lot for washing and cleaning (or just changing wheels for terrain). That is more variable load and clamping action on a very small area……
Fair enough. Respect. We all make mistakes. Good Man for putting it right. I agree and do not like the serrated Washer.
ok. I have checked the prices for ZF gearbox. And looks like, it's price less than the xx groupset, lol.
A thread in a thread always makes me uncomfortable. If they are both right handed will you need 2 wrenches to loosen /tighten the axle ? Won’t snugging the axle loosen the derailleur?
They are opposite hand threads.
Ouch 😮. That's maybe why they want 35Nm torque on the derailleur side?
@@bigalsbashso loosening the axle loosens the derailleur?
@Brian Bob no, its tight on the rear drop out but then gets pulled hard against the bearing spacer under the cassette when the axle is tightened.
@@brianbob7514 no, the mech is still held in place without the axle, I was wrong about the left hand thread though, the UDH is left hand but the mech clamp is right hand
We've all seen how well frame manufacturers can adhere to specification even when it is critical to function. Back to threaded bbs so soon, at least bike shops can face those bb shells when they mess it up lol
Love the integrity. And totally get that abt wanting to get it right. Loads of CZcamsr could learn from this. Loads of them never address errors in gernal not just mtb. So yeah still love the derailleur tho. But not gonna upgrade from. My eagle axs tbh
Did I come first!
Yes indeed 👍
No Hambini, you didn't cum first.
don't you always?
Isn't it a bit late for a 5 year old? To bed now!
No I thought your hairdresser came first?
just on the matter of the tolerances SRAM specifies. There has to be some tolerances applied. This isn't the civil engineering industry where everything gets measured on a thumbsuck and a plan is made to make parts line up :), the mounting system has to work in a degree of tolerance build up. Bike Industry may not be Civil Eng but sometimes I wonder because often plans do need to be made to get things to join. That said, the Stub axle is designed to work within a degree of tolerance build up and looks like it can accommodate a few mm either way (based on bikes being raced since last year I've had the chance to take a close look at and the bits as presented. There has to be a degree of fit adjustability and there has to be a specification for bike frame manufacturers to target ( i say that seriously and tongue in cheek at the same time). So yes tolerance is important in any worthwhile Eng Std. What I stand by is the ability for the system to be aligned during set up by the thru axle because that is exactly a step in the installation. A knock on effect of the UDH std is that manufacturers will find it harder to move an outside of tolerance product out of the warehouse onto the shop floor because the parts won't line up and therefore less chance of the consumer being saddled with a lemon they have to Civil Eng to get working. But there is enough play in the installation to allow for correct alignment of parts quickly which is a step forward for the bike shop mechanic. Just a pity they won't be moving much at the current pricing or maybe I'm just poor :)
Never dropped a hanger, I have however blown out a few sram red mechanical derailluer springs. 😂
Winteresting, go on
Great videos, I love being able to see the nitty-gritty details of bike design discussed like this. However, I'm not understanding your concern with transferring the load into the thru axle to then be transmitted into a carbon frame. This is the exact pathway every impact and load from the rear wheel (rocks, roots, jumps) is transferred to the dropouts. Sure a side impact to the derailleur won't benefit from being damped by the tire but the magnitude will almost never be at the same level as what it is already taking.
I would imagine that if the derailleur gets snagged on a rock or a tree stump whilst moving at any kind of speed, the forces going into the frame will be orders of magnitude higher than those generated by the wheels going over bumps.
All of those forces you mention are acting upon the strongest plane of the bicycle
Rearward impact tears the dropout face.
Side impact transmits more impact to frame
Than a traditional hanger..
Hey with these critiques of the SRAM design, how about taking a look at the LAL supadrive?
I will take a look. As you rightly say 'critiquing', i will reiterate for others - I am not criticising SRAM. I am critiquing a design. Every engineer with a passion for his/her field WILL have an opinion on a design, released or unreleased. That's what makes us tick. I'm not forcing anyone to watch this, but judging by friends and forums people are sick to the back balls of the unpalatable blanket bombing marketing videos. CZcams is an open platform.
For sure, appreciate the engineering analysis, every design should stand up to analysis!
Not sure how I feel about the viscoelastic creep commentary. It sounds theoretically correct, however I doubt SRAM would implement a component with such a failure mode. Surely, SRAM has accounted or has done cyclic testing on the serrated/knurled part and the assembly.
Doesn't that knurl washer sit on the outer edge of the metal bush that you put through drop out?
That's what I thought ?
I would love to know for sure, it just doesn't make sense for it to sit against the frame.
I think its weird how basically every bike channel on CZcams has been going hard on this product and only saying great things about it. SRAM had to have thrown a ton of money at this rollout. I think you're right that this is not the best idea. Thanks for your honest opinion!
@@antoinedoinell Yeah exactly
Getting interesting
Also, not for bikes with upper idler. Chain must be horizontal at sag.
I am a bike mechanic what are newtonmeters?
Nice presentation. Tech ocd 😂. The system is what it is with all its benefits and problems which will be shown in future but that chain powerlock not beeing reusable after removing the chain makes me really wonder if Sram got all other things just right? I mean c'mon Sram, wtf?
In the picture looks like the chain is waxed from the factory
Remember kids, it's not a bike ride unless your derailleur gets directly kicked by a donkey at least twice.
If an impact is catastrophic enough, the serrated washer will just wreck the carbon dropouts. What's the fix for that? Hire a carbon repairman?
okay, so think about it: German engineers actually wanted to make the tension wheel without holes, but it was too heavy... so they thought: "Hey, let's try this overfuckingengineering method. And It worked, so they just said: "Just leave it, it'll be a coolness factor".
Try making jockey and pulley wheel not hollow, and check the difference
There is alot of support for the content you put out on this , personally I feel it was a little disrespectful to thd engineers/product designers (you're peers) calling much of it turd , embarrassing oversight etc when you hadn't used thd product or more important, you hadn't understood the design. Many people had pointed out on original video you're facts where not correct. We all mzkd mistakes granted but the content you put out was not sound or verified, it was you're opinion and that's allowed but how you rubbished the product or certain aspects was unfounded. If you had used the product , had it in you're hand , disassembled it put it back together then you could have put out you're findings. But to do so simply by looking at images from other sites and some diagram online didn't work out to well. It may be you're over view is somewhat correct down the line, but his it was presented in the present doest look great.
I came to this video because my friend had problems with this rear derailleur. The chain became loose in the middle of the ride(specialized epic S-works). Loosening the 35Nm Bolt using only Swat 8mm allen key was not possible for us. Me and two friends tried without success. Sram lost some points!!
While watching this video I also want to be an engineer
I actually*have* seen a German video where a SRAM employee is literally saying that the thru-axle/hub takes/absorbs the impact.
Fellow engineer, why are you stating load in units of mass instead of force?
SRAM commented that it won't damage the frame. I'll mention your vid!
Can someone explain why there is a circular gap in the knurling?
I think it may be a relief channel for the bushing end. If the dropout width is slightly undersized, the bushing end can sit in that recess without affecting the overall clamping. Just an idea. Seems to be the same dia as the bushing.
@@PeakTorque Oh, thanks. I'm not an engineer but I always find it interesting to learn things from your field. That's why I like your videos.
By the way, Sram does claim that the load goes directly to the through axle. I just watched a german video from "enjoyyourbike" channel interviewing the chief engineer where he makes the claim.
One key point highly relevant to weight-weanies (most of us!) Is this new mech weighs nearly DOUBLE a Shimano XT (786) mech at a tenth of the price. And bear in mind that is unsprung weight, the worse kind on any vehicle.
The serrated washer bump-stop is such a good point! I suspect the only reason they did not include a raised section to impact the frame stop would be for aesthetics? Personally if I was purchasing this derailleur I'd be inclined to saw part of the serrated washer off so the derailleur will just keep rotating far beyond 60 degrees. Usually those big impacts are happening in the smallest few cogs where there is plenty of excess chain, so I see no risk of snapping it