Why 2x Drivetrains Have Redundant Gear Combinations
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- čas přidán 10. 02. 2024
- Nerding out on drivetrain math. Why overlap in 2x drivetrains is actually necessary. What does it take to make a zero overlap 2x system?
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“less of a redundancy, more of an efficiency” is a great way of putting it. speaking as a 3by-or-Die Guy, gear ratio overlaps of 2-3by drivetrains are a feature, not a bug.
love the video!
solid thesis
Slow shifting is a feature🙃
@@veganpotterthevegan more gear inch interval is definitely a feature
@03blackoperandi more gears you won't use isn't
@@veganpotterthevegan Sure, if you put wrong gear.
I was not expecting MATLAB in this video but I love to see it. Well done.
Sometimes it has to be done 😆
"Overlap" is completely missing the point. Could care less about overlap - it's irrelevant. It's the tails of unique gear ratios outside of the "overlap" that matter. I have 2X or 3X on all my bikes. My 3X10 touring bike actually has a 600% range and 15 different gear ratios outside of the overlap. More unique gear ratios are great for maintaining cadence in different riding conditions (flat, downhill, wind, or uphill), and can maintain efficient chain angles. I don't shift between chainrings often - typically only when riding conditions change drastically. Show me a 1x15 drivetrain that has small steps between cogs and doesn't have wildly inefficient chain angle. But if someone prefers the simplicity of 1X, I understand.
I understand why the average cyclist has no interest in gear ratio optimization, let alone people who just pedal once in a blue moon.
But once you take a slight interest, I have zero understanding why any road or gravel cyclist, or even XC sometimes, would prefer a 1x drivetrain.
Most people use brifters so I get why triples aren't worth their time since they're a pain when you can't trim via friction shifting. But doubles are so much cheaper, more useful, and take very little thinking to use. More range, more precise gearing changes, less expensive components, longer lived components, less noise from hearing the drivetrain grinding itself on the extreme ends of the cassette...etc.
I have a 40 chainring & a 10x50 cassette on one of my gravel bikes in my opinion it's the best setup.
@@michaeloderda4513 I can see a 1x being good enough if you truly only use your gravel bike on gravel and don't mind large gaps between gears! But I prefer a triple since I live in a very hilly area with lots of rides that mix asphalt/gravel.
@michaeloderda4513 that's not the best setup. Try my setup: 11-46t cassette with 46/30 chainrings. That's a better setup. Best of both worlds.
@@Primifluous I have 2 HC climbs in my backyard. I'm quite comfy riding 1x when I'm riding alone. It mostly sucks riding in a paceline or if my coach has me in a power range I can't sustain with their recommended cadence.
To me the biggest unspoken benefit of 2x is the combo shift: a front shift and a mere two in back is the equivalent of shifting across 5 cogs while preserving a decent chain line. On rolling steep hills, this is extremely useful. Conversely, sometimes it’s beneficial to stay in one chainring and run through most of the cassette, sometimes requiring trim up front but frequently not. The 2x allows both in the same setup.
‘The combo shift’ ! I’ve never had a name for it 🙌
@@TheBikeSaucedual shift is definitely a more experiences riders technique & I now can land in the most efficient gear without thinking using this method & can maintain the correct cadence for the terrain
With the overlaps in a 2X system, you can spend more time in either chainring while using more of the cassette. This saves wear on the chainrings by spreading out the duty cycles more evenly. With a 70% overlap, you could theoretically be in either chainring 70% of the time. That’s financially efficient!
But you have to buy 2 Chainrings, so double the cost. Sounds stupid.
@@biobirne inner chainrings cost a lot less than outer chainrings, so if you can spend more time in the smaller ring, you can avoid having to replace the outer ring. For instance, an Ultegra inner ring for a 50/34 crankset is $19.00. The outer chainring is $157.00
Ok I am not aware of this huge Difference in pricing lol, thats crazy
@@biobirne it’s even worse if you have Dura Ace. The outer ring costs about 10 times the price of the inner ring.
@biobirne you don't have to replace them together... still a fan of both 1x and 2x but chainring wear is largely not a thought. I do get longer life out of 1x cassettes though
Can we take just a moment to appreciate the coordinated graph colors with the channel logo colors? Even the orientation of the pink on the bottom and blue on top! I freaking love this channel. Keep up the great work, Nolan, and thanks for all the satisfying nerdery!
I thought no one would notice!
Good video. This is the kind of thing that Sheldon Brown and Frank Berto used to write about back in the 80's/90's (See Berto's book "Upgrading Your Bike" as an example). Berto coined the term "Gearfreaking", mostly to refer to touring cyclists bitd who were trying to get wide range gearing with gaps between gears that weren't too large, all while running he 5 or 6 sped freewheels of the day. Look up "Half Step Plus Granny" setups. Both those guys have written plenty about those, as has Grant Petersen, who was friends with both of them.
All legends
Love the bike math. I've made too many spreadsheets about my drivetrain ranges. The bike I ride most often is 2x10 and even with overthinking and analyzing this sort of thing it has pretty much boiled down to big ring down hill and small ring uphill. With my 42-28 switching rings almost always puts me pretty close to where I want to be when the slope of the ground changes direction.
One of the things I like about y two-by system is that when there's a big hill ahead, I an drop to the small ring, and quickly have access to a range of gears that will be useful on the hill, without having to worry about getting across many cogs in the back (often requiring multiple shifts).
Unless you're using friction shifters, then you can sweep across and trim as many gears as you like, while being more efficient
Absolutely! This is what I did with my 3x10 XT. I often used the front switch to move to a different ring quickly. But I must say shifting has come a long way and with a 1x12 XT I can drop down 4 gears with one hard press. And with two presses I can down 8 gears. And you can do that under full load. So that is useful to when going uphill immediately after a downhill.
Or electronic! Just hold the button until you have the gear you want.@@tmayberry7559
Shifters have allowed foe multiple shifts down for a good while, my Sram X9 can downwhift 4 speeds with one lever pull, so it takes no time to go down, also the shimano hyperglide behaves great with it wich also helps
I also appreciate both 1X and 2X systems, even the occasional 3X has its place in my opinion. In addition to a more efficient drivetrain and smaller steps between gears, multi chainring set ups can offer a much wider over all range , a higher high gear and a lower low gear, often for a much lower price. An 11-50 tooth cassette, 1X derailleur and a narrow-wide chainring can get quite expensive. One can achieve the same or larger overall range from a 2X or 3X system often for pennies if you are willing to dig through the parts bins at your local bike co-op and/or run friction shifting. Don't get me wrong, 1X is beautiful in its simplicity and very user friendly but as a mechanic and cyclo-tourist I don't see myself ever moving away from multi chainring systems anytime soon. Great video Nolan!
Absolutely. As I only had one bike I liked the versatility of my 3x10 XT. It was able to go anywhere with any luggage. Now as I have bikes for specific uses I like the simplicity of 1x12 XT and GRX.
My view is that unless you're riding the same route all the time there's no better way to quickly dump-down or ramp-up the gears for unexpected downhills and uphills....It's a one-click-wonder👍🏻
Idk, I have a 1x and I’ve never had a hill come up too quickly to where I couldn’t just ratchet the shifter a couple times and make a quick shift to the bigger rings - really not hard at all. Your brain does this weird thing after riding 1x for awhile where the drivetrain just disappears, you stop thinking about it.
@@Ferrichromei've definitely had that experience on my 1x bikes that have just the one cog 😉
@@hugejackedman1951 indeed, sounds nice but too many hills in my area 😭
Nice job professor. You really did your research.
In the 1970s I looked at 2x overlap but found it welcome. A 60 inch gear for instance on the low front and mid freewheel (no cassettes then) could be had with a big front and bigger rear cog. It was nice to have a favorite gear on both the big or smaller front ring depending on the terrain and wind.
I've never tried 1x, mostly 2x and some 3x and of course much single speed as a kid. They all have their place as you explained. And I think that's the point.
You make me feel seen!!! I could nerd out about gear ratios all day long. And way to science the sh*t out of the topic.
I try to design my road/gravel 2x systems so that each ring can essentially operate as a 1X in two distinct environments: big ring for flats and rollers; small ring for sustained climbs or stair-steps. That gives me finer granularity in both situations.
I appreciate 1X systems on my MTB where I am constantly making big gear changes - so big gaps and large total range are a plus.
Closing rant - anything above 8s systems almost universally use spiders/carriers for the largest sprockets which precludes customizing cassettes. There are few stock cassettes that I like: I prefer tight ratios in the high end, larger jumps in the low end. I understand the logic of carriers, but it feels like the engineers designing cassettes don’t actually ride them.
Couldn’t agree more! Check my comment above. Cassette gradations need a rethink
Custom cassettes allow some worthwhile mods. You can even file the wide lands on a cog to allow better ramp alignment! Have made 9 of ten hub mods for 126mm dropouts, but only works in friction mode. 1979 meets the current day!
I love these videos where you geek out on bike tech. I remember one where you measured rotor temp after hard braking. Keep it up!
The article "Gear Issue: Friction differences between 1X and 2X drivetrains" is helpful. It demonstrates both systems in a chart.
For example, 39x11 loses 4.5 more watts comparing ot 53x15, despite having almost the same ratio (3.54). I suspect cross-chaining also wears out components faster.
I bike-camped across the country in 1986 lugging 40+ lbs (carrying 2 extra gallons of water in the desert), averaging 95 miles per day, wearing cleats and clips, on a Trek 700 with 27" wheels and half-step plus granny gearing. My Chainrings were 48 and 44 with a 26-tooth granny, and my 5-speed sprocket was 13, 15, 18, 21, 26. There was no overlap (except the two highest gears when I was in the granny). To get 10 reasonably spaced, useable gears on a five-speed with lots of miles of riding in the flatlands was critical, and granny made every hill I met doable, even if some were challenging. The big complaint about half-step gearing was that the shift pattern was difficult, but the reality is that got used to it very quickly, and most of the time I would sit on one of the chainrings and just shift the rear because most of the time the full steps are what you wanted. But riding those miles with that weight meant having the right gear was critical, and this setup allowed me to make small, but important adjustments, especially when riding for hours into a Kansas headwind.
I feel like you should mention chain line in here somewhere. Not cross-chaining, but the more extreme ends of 1x gearing. It isn't a problem on slacker gravel bikes but the chainstay on a race-orientated road bike is going to be so short that the highest and lowest gears on a 1x setup are going to be unavoidably noisy for a gear range comparible to a 2x equivalent. 2x for road, 1x for gravel, don't need MATLAB for that calculation!
Chain angle is bad on 1x for sure. Chain line is something different tho
Absolutely excellent. Nice visualisation. Good work!
This is one of the best videos on the topic. Using Matlab is a great approach to analyze the issue. Thank you so much for the awesome work.
Outstanding bike nerdery! As someone that rides loaded pannier tours as well as graveling and even XC mtn biking, I've got bikes with all 3 systems, and they each have their "day in the sun" as it were. My latest tourer is my first to have a 2X, and I fear I might miss the "fine tuneability" afforded by the 3x when you're climbing steep passes and then flying down the other side. We'll see. Great content per usual. Keep up the good work.
I am a fan of 1x. For most applications, it’s simple, easy, and adequate. But for my pure road bikes (I have A LOT of bikes), I go 2x. You really can’t get the needed top end gearing for fast riding. So both have a place.
The hard core touring guys are going to chime in about 3x. Yeah, I get it. Super low-end is sometimes needed. But when it’s THAT low, I’ll just walk.
There you go. Thx for keeping it civil 🤘
Overlap is actually something desired in 2x or 3x drivetrains. You want the flexibility to change whether gear changes give you a large jump or a small jump in the gear ratio. You want large jumps if you are cycling in terrain where your speed/ load varies drastically, smaller jumps if the terrain has you going a more constant speed/ load. The increased gear ratio range is only one of the many reasons you'd want a 2x or 3x, and eliminating overlap would defeat half the purpose.
WOW!!! This is the reason why I'm a subscriber 😎👍 Awesome content! 💯
This was awesome, thanks
Great video. Funnily enough I've been contemplating going to 1x on my gravel bike but since I use it mostly on the road for commuting, I've been hesitant and this clarifies the argument I had in my head for staying with 2x. On the road, I prefer the larger 46t ring since you're tend to travel at higher speeds and gravel I sit comfy in the little 30t with plenty of range with a 11-36t 11sp cassette.
I only have a mountain bike, but I use it for commutes as well as trail riding, and one of my biggest frustrations when I'm on the road is running out of gears for keeping up with traffic, but if I made the front cog much bigger I'd lose out on that easy climbing gear (rear is currently maxed out at 11-46t, front is a 32t). So I'm definitely also leaning towards 2x for the eventual gravel bike on my wishlist; besides the fact that it'd be for riding different routes than the 1x MTB to begin with, I think it makes sense in that context of still wanting to have a good few climbing gears but also a nice range for doing those faster sections of flat road and such.
Unless you're in an area with a lot of flats and only occasional mild hills, or it's all hills, etc, I think having that extra range is just a good thing, when you know you'll be riding routes that get a little of everything.
Overlap has never been a big concern for me. I've never done the math like you've done, but I've always assumed some overlap existed. I just prefer the feel of the smaller jumps between cogs in a 2X cassette. That and it's what I'm used to. I started riding decades before modern 1X setups were even an option.
I like 2x systems. I've spent most of my riding over the last few years towing a WeeHoo kid trailer, so the lower gearing is critical. Also, I like having a bail-out if I turn a corner and find a hill i wasn't ready for.
I was fine w/ 3x on my old Surly LHT, & I’ll say Ive really enjoyed the switch to 2x wide-low on my new bike, as this system has plenty of range, maximizes efficiency of overlap by having significantly different ring sizes, while retaining smooth ride-ability when shifting between rings when in advisable gears in the cassette.
yeah i would argue 3x is dead on modern drivetrains for good reason but i would never want to get rid of my 2nd chain ring on my road bike.
I've been through this exercise many times, I used MathCAD. As you pointed out there is a big difference between theory and practice with the change over from big-big to small-small - or,more importantly, the other way round. I take part in sportive each year on which there is an 18% downhill section with an almost 90 deg curve at the bottom followed by about 200 to 300m of 15% uphill - so you have to slow down almost to a standstill with no coasting up the other side of the hill. I had 50-34 on the front and a 10 speed 11-36 on the rear. Having to change from big-small to small big requires a major thought exercise as the 105 long cage derailleur I have is at its limits. The 34/36 combo is not low enough to get up the hill. I have now switched to 46-30 on the front, 30 being the smallest ring the 110 bcd - 5arm crank will take. I'm switching to 11-42 on the rear - the 116 link chain will just manage that but the derailleur is maxed out on the 30/42 combination. The ratio (5/7 or 0.71) is much better for getting up that steep section and it helps on many of the other uphill sections. We have steep sided glens and the down/up combos are often 15 to 18% either side - not too long but still hard work for 200 to 400m of ascent over and over again.
11-42 cassette 11 speed and a 2X 26/39 works very well for me. I have also used a 24/38 chainring as well. This is for gravel and mountain bike setups. Keep up the great work.
My 2013 mtb had that Sram 39-26 spider with Sram front derailleur. That thing shifted like butter. So smooth. Better than any of my road bikes.
My checkpoint grx 2x. My monster gravel steel Velo piolet is 1x. Maybe it’s just a personal choice like picking a saddle. I love your videos so much
My electronic groupset has a mode where you just shift up or down and don't have to deal with the distinction between cassette and chainring. But I never use it because it's really useful to be able to change the gear ratio by a large amount all at once when the terrain changes
Great info. Glad someone did the math about it. Always thought there was some kinda redundancy with 2x systems. I'm just a basic road commuter with a 1x system and that works for me cuz I don't do big hills any more then over passes. A single speed would work for me but I do use other gears time to time,,,,I was just thinking about the redundancy in the overlap area in the graph in that when in the small chainring the mechanical advantage would be more then it would be in the big one due to the crank arm length. I'm not an engineer, but just a simple bus mechanic. I'm thinking of the amount of force to turn such ratios givin the crank length. Maybe another video? Hope I got my idea across. Again, great video & glad you did the math. Keep'em coming!
Well folks, before jumping in with all the math, we have to look at semi-trailer truck transmissions.Those with three shift sticks to be precise.
One of them being the main selector, another for the splitter (or demultiplier) and last one for multiplier. These additional sticks control moving the whole gear range 1L-2L-3L-4L-1H-2H-3H-4H with zero overlap and shifting it just sligthly so that the gears alternate 1l-1h-2l-2h-... One is used for when the loads differ much (you have a trailer or not, ride great uphill/downhill slope, etc) another when the load increases gradually (entered a headwind, gradually changing slope or rougher road surface).
Long lecture past, 2-by in cycling transmissions works as a combination of both splitter and multiplier in trucks. And this is trully amazing you don't need a third lever to get most of the funtionality.
Btw, in 11-34x62/20 there is still some overlap with ratios of 1,824 for 62x43 and 1,818 for 20/11. So yeah, pen and paper beats computer...
62x43? there's no 43 on the cassette. did you mean 62x34?
@@ramensospicy2992 oh, yes, of course. German way of counting plays games with my mind sometimes
I have an Excel spreadsheet that does the same thing. I also have some internal hubs (Rohloff and Shimano Alfine 11) in there too for selecting chain rings with those.
Regarding cross-chaining, if you intend to avoid using the Big ring with the top two cogs at of the rear cassette, and similarly with small ring with the smallest two cogs, then, for example the 50-34, 11-30T 12 speed overlap reduces to just 16%, which doesn't seem like much wasted at all.
The old 3 speed from back in the day handled a lot of needs
You can only use 1 gear at a time, so redundancy just spreads out the wear.
🤯 great point
I rode my 2x 11 GRX for about 2 years and I really liked it in hilly terrain. I just had to drop to the small ring and about 2 or 3 sprockets back and boom.... almost the same gear but with more smaller gears to come.
Range matters for me with a low bottom gear. My go to bike is a GRX 400. 46 30 chainring, 11 36 cassette.
I have the same config!
FWIW, the new GRX 12-speed has just a touch more range with 42 front and 10-51T back. I'm not going to upgrade any time soon, but I'd probably put that on any new bike I'm buying for simplicity.
@@matt.3.14 👍🏻 looking forward to the upgrade.
2x for me running GRX 31/48 up front with XT 11/42 rear on flat bar setup this setup works well for my riding style of road to MTB trails.
Good video. I’m a 1x runner, but one big thing i like about 2x is if someone is a flatter ground rider or tend to ride the same route, they don’t wear out the same 1-2 gears. Redundancy can double the life of their cassette if they have overlap in that frequent pocket. It’s sad to replace nice cassettes with one worn cog. but good new front derailleurs that work with anything but 1 named gruppo are rare.
Good point. Those 1x cassettes aren't cheap to replace either.
Ditto the good point, I commute on a 1x9 setup and 70% of the time I'm in one of two cogs, probably bumps up to 90% for being in one of three/four. Already had to replace a cassette as well (though it was a cheapo one so can't pin the blame on it just being regular wear). I've definitely had times worrying that I'm putting the majority of the wear on only a couple cogs.
A non front derailleur based 2x alternative with no overlap and usable gear range:
50 tooth front chainring
12-28 tooth rear cassette
Schlumpf Mountain drive (250% reduction)
Gear inches:
50x28 (low): 19.3- eagle equivalent
50x12 (low): 45
50x28 (high): 48.2
50x12 (high): 112.5- you'd be hard pressed to spin it out on descents.
The single chainring up front reduces the negatives of cross chaining. The gear range is also somewhat obscene- it could be reduced at the rear cassette and run with a narrower block 7 speed cassette. This again improves chainline, reliability of shifting and user experience of scaling the entire cassette in the middle of your range. Some shifters are better at such leaps, with many able to do 4 per click. Friction based setups (eg genevalle) can scale or dump the whole cassette in one go, though you wouldn't want to be putting down much power at the time.
A pretty silly setup still, but I could absolutely see it in use on loaded tourers and bikepacking bikes.
Recently built up an old road bike with parts bin parts. 53/39 with 12-28 6 speed freewheel. with thumby friction shifters. Was great. As long as I can have a reasonably low gear I can deal with any drivetrain setup. My preference is 8 or less speeds and 2x or 3x, but 1x with wide range cassettes is fine too. Luckily most shifters can dump gears/downshift 3+ gears on 1x so mtbing is fine. I do prefer my twist shift since I can adjust trim and it's indexed while being able to upshift or downshift the whole cassette. I also enjoy single speed road riding since on hills it's "do or die(walk)".
Awesome vid! I love all this theoretical science stuff!!
As for me, I like both drive trains as well. Bikes where I want the most range and the where I’ll be pedaling a lot longer prefer a 2x
For a more fun MTB or just cruising around I like the simplicity of a 1x
Nice. The super nerdy vids generally tank, but I enjoy making them 😆
@@TheBikeSaucepls don’t stop. there’s a bunch of OCD High Functioning Autistic Bike Nerds like me who rejoice in this kinda stuff. You (and peak torque) are our voice to the world 😂
I've got a couple 3x on 90's MTB's, a couple 2x (1 road, one MTB), and five1x drive trains (1 gravel, 3 MTB's, and tandem). Honestly I prefer the 1x system a bit more than 2x in all cases. I used my gravel bike with 1x as a road bike far more often then my 2X true road bike and it only took a couple rides to get over the annoyance of larger steps. If I were stronger I might wish for a taller gear, but I'm not, and spinning out has not been an issue, but the multiple granny gears has been a real bonus on my usual hilly loop.
Ha! Interesting topic and nicely presented. Thumbs up for the annotated Matlab code! So, I have an older 2x gravel bike with 50/34 chain rings and 11-42 (10 sp) cassette and a newer 1x gravel bike with a 44t chain ring and 10-50. My biggest beef with BOTH drive trains is that, unlike my road bike, the road-speed ratios on my gravel bikes are spaced too far apart because both cassettes use 2-3 tooth spacing between the cogs that I use on flat road. They are 21-18-15 on the 2x and 18-16-14 on the 1x. So neither system allows fine tuning of cadence as much as I would like. So, for me 2x doesn't really help a whole lot, though I built my 2x bike to have an extra wide range before 1x mullet drive trains were a thing.
I'm curious to know how Sram AXS combinations compare to the trad ratios you focused on and, with electronic shifting, could sequential programming of the shifting (with the right rings an cassette) obviate redundancy with smaller gear steps?
I'm running 11s 11-45 grx with a sram 43/30 chainrings.
I use it mostly as a 1x, the 30t is there for me to get that low low gear. I call it a 1.5 by 😂
Have tried to go 11-50 on the back but that forces me to switch chainrings if I want to access the top cogs on the cassette.
I think the chain angle pushes the chain from the 43 ring to the 30 ring, but it doesn't do that on the 11-45 cassette for some reason I can't figure out 🤔 both cassettes are shimano cues, could it be the thickness??
Im hooked! All that's left is to apply it to a physical bike! :)
He did the math so I could have one less random thought experiment keeping me up at night.
thanks for doing this, there is nothing worse in a silly debate than lack or research or data. However for me this needs refining with two important factors: 1) usability of a gear ratio, i.e. how long does or can a rider actually spend in any of these gears: if you look at di2 stats, most riders spend 60% of their time in just 3-4 gears with 2x, and some gears only 1-3% which probably means those gears were not actually used at all and the 1% time just represents the time
needed to transition between gears that are actually used. with 1x the spread of time across gears is wider. if the 33% of non overlap
is mostly gears that are just in the way if gears we actually use then we have a bigger problem, or 67% is less of a problem if the opposite is true. 2) efficiency, for years we have been told that 10t was “too inefficient” and 9t verboten. but I have PB sprints on all by favourite top gear segments in these gears vs 11t as the “efficiency” losses are way less than max power variations of human legs, as well as changes in drag from variables like wind direction or wind speed and so these gear combinations inefficiencies are negligible/ irrelevant. on this efficiency - my chains are lasting longer on 1x systems than my 2x systems. My only theory on why this could be is either that the chain angles are kinder or that if a 2x system is making you wear out 4 of 24 gears vs 1x spreading the usage more evenly over 8 gears of 12 then that would probably outweigh any theoretical efficiency which assumes all fresh gears??? either way, a gearing setup overlaps is only part if the story without taking into account how much we actually use any of the gears and how many gears in between them are only transition gears we actually never use but are just getting in the way of gears we do use. And that is before we get into the gear jumps! more math please with gear jumps and mapping time gears are actually used and chucking out the gear that are essentially only used to get to other gears!
Your video inspired me to try to find some way to fix the cross chaining problem on a 1x setup, and theres already a few patents for it. US5085053A was a specific patent I found. Any thoughts on something like this? Could I make a perfect 1x12 setup with no cross chaining? Didnt find any examples of this product for sale
Thanks for the video. I always try and make my gear ratios when they overlap between chain rings non-redundant. That is your two different plot colors not appear on top of one another. That allows for additional resolution in the finite number of gear choices. That may require some hunting between chainrings.... ( ever hear of half step granny gearing). Hey, how do you afford a Matlab license?
License is through work 🤫
Granularity and finding the perfect cadence favors 2x, I had to splice together my own 1x11 cassette in 1 tooth increments just to find that perfect cadence and Granularity, beeing cadence picky on a 1x is a living he!! Lol
With electronic shifting it would be possible to effectively eliminate most or all overlap by just using a single shifter where it operates both dérailleurs... shifting the front one half way through the cassette to always maintain a straight chain line. I feel like this is actually something shimano has already done before?... maybe you just have a couple of cogs on the middle of the cassette be used on both rings to compensate for the large jump when shifting the front one.
2001 Bianchi Strada gravel bike is 1x Microshift Advent X )2 setups, drop bar and flat bar) 96 Giant Iguana mtn bike 1x Deore, Detroit Bikes Single speed 1x, and 96 Vitus 2x Dura Ace.
I ride a 2x11 set up running 53/39t chainrings and a 12-25t cassette, but to avoid cross chaining I only use the sprockets 1-9, ie 25-14t, with the 39t inner ring and then only use the outer 3-11 sprockets, ie 21-12t, with the 53t outer chainring.
So I don’t use the inner two sprockets when on the outer ring and the outer two sprockets when on the inner ring. This gives me quite minimal real world overlap, which also means I don’t have many sprockets to switch up or down through when switching between chainrings.
The religiosity of the 1x vs. 2x thing has been interesting to watch unfold over the last decade. I look at it like singlespeed or fixed. More options for cyclists to explore, ride and tinker is a good thing. All of these options have their utility. But getting heated on the internet over someone else's gear choice (just look at the comment reply threads in here), will always confound me.
Church! Would love to see the breakdown on an old school wide step double, a la 40/24 chainrings with an 11-36 cassette
No sure if it's correct, but I like the idea of making climbing easier lol, so focused on 1x and preserving the low gears just to chill and make climbing easier. Def spin out on top end going down but I take a moment to take in the view and enjoy the break. The headwinds on the flats wouldn't let me enjoy the high end gears. I appreciate that 2x gives the option tho. It's there if you want it and those who like to have it, all the better to them.
what are people’s favorite front derailleurs for doing odd chainring combo doubles? preferably for 135/142 rear ends.
im still on 3x9 , with a 22 , 32 and 44 rings on the crank and 11-34 in the back , the big chainring is nice for the downhills to get that massive speed while staying at a relatively more comfortable cadence
if i want to drop a ring i need to shift up 2 to 3 gears on the casette to be at a similar cadence to what i was at the shift, as for the 22 ring , it has extremely low mileage as i only really use it for really gnarl steep climbs on days where the heat saps my power , also worth mentioning i ride mtb and idk how accurate garmin weather data is but i have the bad habit of going on days that are hot (30c-36c) and with the super high heat thats usually when i use the 22 ring 😁
Great video. I really like both. I prefer a 1x on my Mountainbike and for almost everything else 2x. On my gravel/randonneur bike is a 32/44 with a microshift advent 11 to 42 cassette. Couldn't wish for a 1x there and on my mountainbike is a 1x12 deore. Completely different setups with completely different use categorys. In my opinion overlap doesen't matter too much, because you usually don't use the overlapping gears too much. But I can always reccomend singlespeeding to apreciate any gear system😂
If you had something like the classified hub gear system you could run something with a much smaller overlap feasibly because the chain lines won’t be as extreme. What limits you probably would be how much you’d have to shift on the cassette to maintain a similar cadence when you’re shifting between the ‘big’ and ‘small’ gear.
I've thought about this too. A classified system with like a 0.4:1 low range would be really interesting. You'd still have to dump a lot of gears between switches, but with modern controls being able to dump 3-4 gears going down and 2 up, it seems like a second or two of pedaling easy.
Generally, on my mtbs I ride with 1x, although my hardtail is a 2x 10. On my tourer I have 2x11. They all work very well, and suit what I use them for. The "overlap" on 2x makes them convenient and manageable. Ix 12 is brilliant on mtb where a messed up change means a dismount.
I understood the convenience of 2x and 3x system only after going 1x. Currently thinking of ways to put a front deraileur on my bike designed to run without it. 1x is lighter and simpler, but sometimes you want that easier gear in the front
I'm running 2x11, 42/22, 11/32 cassette, Force22 WiFli RD, Rival22 levers and GRX400 FD. The 22t is a bailout gear, chainline is offset. It's a 1x 95% of the time and a 2x when needed. Front shifts absolutely fine, not perfect, considering the components available, but working on it. Narrow (road) Q factor.
Cadence is the reason, not gear inches, 2x drivetrain ratios were developed for road riding where cadence is king. The overlaps are very close not 100% overlap for each ratio.
Gravel was technically non existent 10 years ago and lower gearing for touring was already available half a century ago (TA, Stronglight, etc) but the big 3 didn't have any interest in that, only in racing. The good part about it was mtb and road components were 99% interchangeable. Gravel goes mainstream and here we are.
i've just read the title and my comment is that of course they have redundant gear combinations, and that's what makes them nice, you can get the same gear ration with either crank
of course, besides that they have a wider gear ration than 1x drivetrains
I've noticed that if you run small-small worth a large diameter differential in the front cogs, the chain can actually rub on the large cog. This would be a geometric limit unless you have a super long chain
I have 3 chainrings. I have little gear steps, a wide range and overlap helps me to stay in one chainring unless steepness changes dramatically or for long.
Because manufacturerers don't offer good quality bikes with 3x I still ride my 14 year old bike and will continue to do so until I need an e-bike in 10 years.
With zero overlap you would end up riding in the middle and constantly switch chainrings.
Glad to find you! How about putting a planetary up front (they're around) to give you the wide ratio needed to minimize or eliminate ratio redundancy. This reduces crossover losses in two ways( narrower cassette and single line from the front...but introduces losses associated with the use of a planetary. What do those efficiency numbers look like? 'Still have the (practically unworkable) extreme double shift scenario to achieve progressive ratio continuity. Deurs could change to reduce idler length( reduce the risk of damage), shorter chain length, clutches?, reduced mass at rear axle... etc etc Just asking! Great analysis!
Still using a 3x9 today on my oldschool xc bike. The only reason I would upgrade is because of chain retention, and maybe I'll make it a hybrid. Can you imagine installing a narrow-wide chainring in the center, and having to change gears by hand just in case you need to haul a pile of wood or chase some roadies..it actually sounds tempting. No more mud in the FD but my left hand is gonna feel awkward at every shift
Dura ace has an 11-34 cassette, which is what most people really want. I run that with a 54/38 chainring combo for a pretty wide range of well spaced gears. I never feel like I'm dumping cadence or hitting a wall. It's a huge range on tight jumps that 1x can't give.
On my gravel bike I'm running 11s GRX 42t with a 9-50t cassette, big jumps matter less off road.
You did not consider the fully overlapped setup called half stepping. So in your gear ration calculator put in 50-47 for the front and 11-50 for the back.
It's never been about how much speed you would benefit from it but how less the chain has to bent in order to archive that gear ratio you need, thus reduce the stress on the drive chain
That 50/28 would not be completely useless - would be amazing in the mountains where you need climbing gears with small jumps between them, but also a big ring for the descents. The change from small to big would be a hassle, but you'd be on free speed from the descent at that point. The only hard part is going from big/big to the small ring for the next climb.
If you have an 11-21 rear sprocket and a 22-44 front you can have a 1-4x syatem and no duplicate ratios or overlap, it's also quite light.
Alistair Spence mentioned the legacy of Frank Berto and Sheldon Brown, and perhaps it's worth mentioning to the viewers that there are options beyond just 1x or 2x. I've always looked at what gear range I wanted, what the step size between gears should be, and the number of gears. Based on that, I could then decide on whether 1, 2, or 3 chainrings was best and what freewheel or cassette would do the job. The amount of gear overlap between the chainrings does matter, as you note, and everyone has their own tolerance for this. Modern systems have really reduced options and dumbed the whole thing down, unfortunately. Perhaps a future video discussing how to start with one's personal gear specification (step size, etc) and finish with the optimum chainring(s) and cassette that will satisfy the specification??
I’ve never minded the overlap and indeed find it to be beneficial for the actual riding experience, but I’ve always wondered about duplicate ratios. I believe SRAM AXS can be set up to shift sequentially through ratios, seamlessly moving both derailleurs as needed, and that sounds like an interesting thing to try. In that case it would be valuable not to have chainrings and cassette creating exact duplicates, or even ratios so close that it doesn’t make sense to shift through them all.
I feel like you might be missing the advantage of bar-end shifters here. It's really quick to shift through the entire gear range on those. Still, the biggest issue would be the double shifting. That is not going to be a fun experience.
I currently run a 48/28T x 11-32 11-speed setup using a modified Pro-5-Vis crankset. That 20T difference works with an 11-speed Ultegra front derailleur and a chaincatcher but it is more of a bailout gear than a regular riding gear. And I kind of like it that way. I am planning to give 11-36 or even 11-40 in the rear a try in the near future but I might have to drop down to 46 or 44x26 in the front. Derailleur capacity is going to be an issue at this point.
Coincidentally, if you want a real-life crankset that could handle a 26-62 double, the Pro-5-Vis 50.4 BCD standard is your best option. Good luck finding a front derailleur that can shift that though.
Would you consider sharing the Matlab code? I'd love to play around with it
My 1x works great! 1x14, MR Rohloff thank you Sir for years of pleasure!
Tbh IGH and gearboxes are cross chain proof lol.
many times you can get a bigger or smaller ring to widen the gap, it usually works no problem
The cool kids are now starting to run a wide range 2x with 8 or 9 speeds drivetrains. (Ronni Romance). So it would be interesting to see if a 42 - 28 or 40 - 26 (that’s what I am running) on a 9 speed gets closer to the mythical 0 overlap. Thanks for the video.
Interesting data, so 11-25t cassette and 50-34t chainring is only 41% overlap... How does increasing the chainring sizes affect that? (52-36t & 54-38t)
Similar to you, I use both 1x and 2x. They both have their uses.
Thanks for sharing.
Interesting thought experiment… and showing why overlap is included in all gear sets for sale
I did the same calculate on google sheets and MS excel. lol
It need much more big diff between big and small chainring for the zero overlap.
maybe at least 20 or 22 t diff, just like 44-22 or 44-24, it's actually the old school 3x without mid ring.
shimano FD can hold at least 18 t diff, I didn't test the 20 t diff.
before the 10 speed, the drivetrains need mid ring to cover some range, and now it's 12 speed era, the big and small ring can share the job of mid ring.
for most of large cassett, 1 x 12 speed MTB, the lowest range is 0.65-0.67, the small ring 2 x system with small cassette can also reach that ratio on 12 speed road cassette, yes , I mean shimano11-34 and 11-36.
65T with 11-34 cassette to be exact 😆
With the increase of drivetrain options, including things like the classified power shift, gearbox, and electronic shifting, it could be interesting to have an automated shift-over the increase the shift range. Not saying it's a particularly good product for the market, but could an interesting experiment.
With 24- 44 up front, and 11-24 in back, duplicates are few! Flat criterium style jumps at higher speeds , and 5 compensatory shifts toward smaller cogs on 9 speed results. 400% range with small jumps just works. You have to use the Sora band type Fd to shift this. Chainlines aren't great pretending it's a 1x, but 9 speed is inexpensive. Also a 13-36 cassette stays within the 43 tooth wrap max with Sora medium cage Rd. An 18 inch gear for heavy touring! Now that's range.
If you don't want overlapping gears, isn't the half step the obvious answer? 45-50 with rear jumps of 20%. . . Having a Trek 720, I understand why this is tough. But with programmable electronic shifting you could just program the double shifting.
I have nothing against 2x or 3x, but I hate adjusting front derailleurs. It's very flat where I live so I appreciate the simplicity of 1x and the range of a 11 to 51 casette is all I need for that. I understand that there are people with other use cases or different topology to conquer on bike. To each there own, I suppose.
1x - if you're offroad because dropper posts/body language = speed/terrain undulates a lot more
1x or 2x - for mixed-surface depending on if you're a roadie/tourer vs. a MTBer
2 x - for road
3 x - if your bike is real entry level or you're a retro-grouch holding onto what is familiar vs. what is objectively better. Lots of 2x options that provide gearing as low as 3x touring cranksets of old and none of you really use that big 48/50t ring bombing down at 100rpm at 80kph like you think you do...
The engineer in me can appreciate the nerd factor in his analysis
This calculation should be amended and focused on unique/duplicated gear ratios not on overlapping percentage. The issue with 2x and 3x systems is duplicated gear ratios. So first thing is to establish which gear ratios are duplicated: how close is it considered to be duplicated?
2x usually has a better overall range. I am sure with the latest mullet setups that 1x is finally getting close but that was the reason I am staying with 2x.
Can do the same in excel in about 2 min.... I got rid of the worst of my overlap as the overlap is just waste to me. My target was to get the % change between each gear about the same. Its not just the overlap though. having to shift on and off the big gear in front isn't ideal from a user standpoint, and I wanted to minimize front shifting too. I got pretty close. If I were building from scratch, I'd just do 1x and not with a huge cassette either - just a standard 11/28 as its not hilly here. Mine is 50/36 and a 12/25 11 speed. Pretty good.
Currently you define overlap as "what percentage of the possible gears are between the smallest ratio of the big chain ring and the biggest ratio of the smallest chain ring". This definition ignores that there might be still value in having more options in that overlapping zone.
Wouldn't "how many gears have a ratio too close to another gear to be considered two separate gears" be a better metric?
Example on my own 46/30 grx:
I would consider 46/20 = ratio 2.300 and 30/13 = ratio 2.307 as too close together to be two different ratios...
It all depends on what terrain you are riding. Horses for courses.
For the average rider, any miniscule amount of frictional losses 'cross chaining' on a 1x are completely made up for by the reduction in maintenance, ease of use and not having to shift a front derailleur. They are actually the worst. They work most of the time but they are so annoying when they won't shift properly.
On the roads where I ride I very rarely use the small chainring on my road bike. I could easily survive with 1x and I do ride on the road quite often on my gravel/touring bike and never felt like I needed more gears.
People who live where there are actual long steep climbs then yes, 2x is really needed so you have the small ring for long slow climbs and then the big ring for those long fast descents.
I honestly can't see the need for any more than one chainring for any casual rider or commuter. They only have any real value in sport oriented road riding.
One limiting factor in the 2x no overlap idea is that some front derailleurs (if not all) have a limit on how much they can jump between the chainrings.