T47 Bottom Brackets | Full Engineering Guide | Everything you need to know
Vložit
- čas přidán 27. 06. 2024
- A lot of new bikes are coming out with T47 bottom brackets, this video explains what they are and how they work. In my opinion, this is a step in the wrong direction. The addition of an additional threaded connection makes it less stiff and introduces another tolerance and alignment stack.
This is an admission by the bike industry that they are unable to make something to the required tolerances. T47 will generally have a higher system weight and a bonded joint that is liable to galvanic attack.
More info on the technical standard
www.hambini.com/engineering-g...
Buy a T47 BB here
www.hambini.com/product-categ...
DBCA explanation
www.hambini.com/support/faq/d...
Some of the equipment I use and recommend
*THE HAMBINI PENCIL OF CHOICE*
UK Kuru Toga Silver Edition amzn.to/3Y9azT1
US Kuru Toga Silver Edition amzn.to/3jryfmT
*THE HAMBINI HAIRDRESSER PENCIL - iT's PINK*
UK Kuru Toga PINK Pencil amzn.to/3VD5wsj
US Kuru Toga PINK Pencil amzn.to/3Hwthx8
*TOOLS*
Wera Allen/Hex Keys
UK amzn.to/3CdPazi
US amzn.to/3wRG1cD
Wera Screwdrivers
UK amzn.to/3WGqOFS
US amzn.to/3HX6KLu
Mitutoyo Digital Calipers
UK amzn.to/3Gq9Nv6
US amzn.to/3HX6KLu
Mitutoyo Feeler Gauge
UK amzn.to/3Gq9Nv6
US amzn.to/3X4rmp4
Disclaimer: Some of these links may be affiliate links for which the channel gets a small commission, but the price you pay remains the same.
----------------------------------------------------------------------------
Hambini Website www.hambini.com
Facebook / hambinieng
Instagram / hambinieng
If you would like to support the channel for more unbiased reviews, you can do so on Patreon. / hambini - Sport
serious question/point - Hambini, why don't you/will you ? design a proper workable quality 'standard' for production bottom brackets
To expensive?
I don’t think the problem is the standard(s), it’s that the bike industry can’t accurately build frames to them.
@@richardwilliams1728 a can of coke is not too expensive & the engineering & manufacturing tolerance that goes into a ring pull is immense - our hairdresser jockey can do this
@@blackdoublezero every frame is different though so it would mean building a custom BB for each frame.
@@blackdoublezero okay google, what is an economy of scale??
I love my Hambni T47 bottom bracket. My LBS that installed it when building my bike said it was the smoothest BB he's ever seen
I love that newer Cannondale models are now going to be spec'ing T47. They basically pioneered press fit BBs via BB30, and now they're going back to threaded after flipping the industry on its head. Ultimate troll move lol.
“Cannondale quotient” is our universal term for how many proprietary things are on any given bike. It’s a huge pain in the ass.
Yeah, but Crackenfail is 'on the radar'! 😂
At least they're trying to improve in consumer's better interests? Or did they just get tired of warranties and lemon laws?
Lots of the incompetent hacks in this industry still try to defend their shit designs. Like the ABSOLUT Hacks.
Ever since pressfit shit existed, I've been advising folks to cut their losses or find the right sucker to buy your junk.
Get a bike with threads in the BB! I'll never buy anything besides BSA simply because it's very well proven to last and it's so easy to wrench on. Even old school 'junk'. If you struggle with BSA, just leave it to the pros!
Ah, yes, the world does need a Hambini standard. There's no question about that. Nice technical pointing with the high precision mech pencil.
Regards,
Chris
RIP pen check
I am not into cycling at all, however I always watch for all the engineering knowledge.
The other day I saw someone defending manufacturers going back to threaded by saying that it's good for everyone because "It is hard to get the tolerance right for a press-fit BB, so by going threaded we can get rid of the problems (i.e. creaking) of press-fit BB".
I just can't believe that they think the bike companies who sell them 5000 usd frames that somehow can't get the manufacturing tolerances right for a, quoting hambini, "a round hole" can provide them anything of true quality. What I don't like isn't about all the stiffness talks or anything. I am just furious that the bike companies are getting away with putting out inferior products but still charging you the same price, all while talk about how amazing their manufacturing process is, and the fact that people are accepting this.
One of the only good things I see about returning to threaded BB standards is installation and removal uses the same tool. No pullers and presses required (except if you're servicing it).
This is the problem now, anytime I purchase a new bike I'm thinking "Okay, whats going to go wrong on this?" because quality control and development of these products is awful.
Basically manufacturing that relies entirely on Teflon plumbing tape. And the industry wonders why they are in free fall.
I feel that using carbon fiber is a major disadvantage if you need tight dimensional tolerances, especially when said industry spends more on marketing than engineering or manufacturing and does not have the same resources as the bigger players such as the aerospace industry. If you ask any decent frame builder to make a frame from steel or titanium with a press fit bottom bracket there is a good chance you will get better tolerances for less money than say the best carbon frames and without many of the problems such as those aluminum inserts debonding from the carbon. Of course none of the roadies or weight weenies would be very keen to ride a heavier bike with a rounder hole.
@@yonglingng5640 campy entered the chat
truth bombs from Hambini as per, got to let my LBS know about u, thanks for all the info you put to us non-engineering types and thus empowering us when it comes to bike mechanics 🙏❤👊
@Hambini great vid very helpful and to say if they keep moving the goalposts there’s no need to face the core problems . Keep shining the spotlight thanks
Thanks for this great information, Hambini. Having built a couple bikes for myself, figuring out bottom bracket/axle/groupset compatibility is a royal pain.
Top work.
There is some humorous irony that the reason pressfit has developed its poor reputation is because of the Hambini channel. We have been rapidly buying tools for the increased number of T47 we are seeing that need facing after lazy paint jobs. T47 isn’t the answer, more educated mechanics and consumes are! The main advantage is that T47 will be easier for mechanics to fix post production, until they corrode away anyway.
Saying that, I have only seen 1 bonded in BSA fail because of corrosion and that is a tiny fraction of the pressfit problems we fix.
One of the things I have seen first hand is the large amount of consumers going back to their retailers and claiming faulty goods under the consumer rights act. I'd imagine that this has filtered up through to the bike manufacturers who are unhappy at the high level of returns as it costs them a lot of money.
Give it time, I think there will be more bond failures - it's inevitable in damp northern england.
@@Hambini For sure. Frame reports for warranty claims are a notable part of our work now.
Being a pro mechanic in a high end shop the last 7 years has been sorta eye opening. It's become very apparent to me that 'mere QC' is an inconvenient, overpriced, bad joke in this larger cycling industry. A mere sticker applied in ignorance to a product. That's putting it nicely.
I keep my personal precision measuring instruments at the bike shop. Nobody is fooling me!
I retired from machining and quality assurance in high reliability manufacturing.
The number of pressfit shit repairs compared to BSA repairs is quite ironic. We're always special ordering various pressfit shit replacements while the BSA units sit in our inventory and gather dust.....
BB issues are just a drop in the bucket considering all the different quality issues we see on ALL production bikes, from cheapest department store junk to highest end, so called 'pro quality' plastic junk.
I see entry level bikes with cartridge style BSA square taper BBs last for years of daily commuter use. I own high end loose ball square taper Campy and Dura Ace BBs or Phil Wood sealed BBs that are over 30 years old, still smooth and silent. Compared to pressfit shit, BSA bikes suffer very few issues and you can almost always thread and face a BSA shell to allow it to function perfect for years.
I've serviced thousands of hard used carbon Santa Cruz mtbs over many years. I've never seen a single one of their bonded in BSA aluminum shells suffer a single issue. These sort of riders often abuse and neglect bicycles too!
New and improved BB 'standards' were never the answer and never will be.
Until large manufacturers work out their OBVIOUS quality issues , it's business as usual. Until consumers start boycotting and refusing to buy compromised junk, the manufacturers will continue to provide junk! WHY should or would manufacturers IMPROVE, when ignorant consumers create the demand??
@@rollinrat4850 I've been willing to slide on some red lines (cough...internal routing...) but I will never buy a bike that isn't BSA. Not for the least of reasons, I have to do my own maintenance.
@@cjohnson3836 I've never paid anyone to service any of my bikes. I got a flat when I was 8 years old. I showed my dad and he said "learn to fix it or walk". I loved my new found independence so I learned quickly. Best lesson I ever learned was maintaining my own junk. At 10 years old I overhauled my coaster brake hub. My grandfather said DIY so you KNOW it was done correctly.
As far as I'm concerned DIY offers the best potential for the highest quality attainable, simply because nobody can possibly give a shit like the end user whose life relies upon it.
Now I'm a retired machinist and inspector wrenching in a high end bike shop, just for fun and laughs. Nobody is fooling me!! Bicycles have always been my lifelong lifestyle since way back when. I built every one of my bikes up from a bare frame. I've designed and built every one of my dozens of wheels.
My old metal custom frames have lasted for decades. I know personally who built each one. I shook their hands. I'm learning frame building now myself.
I'm restoring a vintage Albert Eisentraut frame from 1977. Right now I'm building a new low trail fork for it. I plan on riding this custom 'all road' bike hard, often in dirt, rando style.
There's only one brand plastic bike I'd ever consider that we sell in our shop. That's Santa Cruz. I could afford one, but my old bikes haven't worn out yet. I've built carbon aerospace hardware. It still orbits the earth. Again, nobody's fooling me.
Three things that will cause me to ignore any new frame: non BSA bb; INFERNAL/integrated routing; (talk about hate!) and non round seat posts. All this junk is job security for me now!
Love these videos explaining the standards.
My take, fwiw: given the actual manufacturing standards in the bike industry, a BSA 68 with 24mm axle makes, by far, the most sense.
Wrong. Those teeny tiny bottom brackets aren’t big enough to route internal hydraulic hoses, but nice try Fred
I've been running BSA30 bottom brackets without any issue for over 40,000km between 2014 and September last year when the bike's replacement arrived. Most of that on the same set of bearings, which remained smooth. Setup was Rotor 3D+ cranks and Power2Max power meter on a Cannondale CAAD9 that had a BSA BB sleeve fitted by the OEM to accept Ultegra cranks. I would happily use that setup again.
The big advantage of the t47 86 for custom frames like mine is that I can clear larger tires with a shorter chainstay since there is more frame material to attach the chainstays to. For road applications, I see the benefits of the 68. Also with the 68, you can put the t47 86 in them to run the older style bb30 cranks.
Look at all those standards! That's the great thing about standards...there's just so many to choose from!
excellent as usual, very informative, thanks
I did a new bike build with the T47A (bbright etc) and it performs fine but was a bit annoying installing it because you need two different tools and as you said, you need perfect tool alignment to get proper engagement with that 2mm while not scratching the frame.
I’ve had BB30 with its aluminium sleeve for 10+ years and never had any issues, so hopefully the sleeve in T47 will not be a problem
Hambini. Great video. Thanks.
Great explanation and very succinctly explained thank you.
I just realized why my four year old doesn’t object when I change the youtube channel to watch your videos….it is the disney blanket on the table that keeps the interest. (FYI- I do turn on captions and mute audio on the more profane videos). How come you haven’t been sued by Disney yet? Better be prepped in advance , b/c if the that blanket goes away…it is going to break some hearts 😉😉😉
So many "standards" must make it difficult to repair and reuse older bits. This must generate a lot of sales.
I think everyone who's been paying attention has been expecting the Pressfit 'standard' to end. And the surest sign I had was when I found a Pressfit press tool on a US website...for $20. Once the tools become aftermarket and cheap, the industry is definitely done with whatever system they "used" to be in love with.
Nice video big thanks Hambini
Always waiting for this "hello!!!"
I have 2 bikes, one with bsa bb and the other with a PF 68mm not a single problem whatsoever! Both are great
All this driven by the belief that a bipedal mammal, that can barely crank out 1/10th of a horsepower, will see a benefit from a 30mm axle vs one that’s 24 or 25 mm.
Well, to be fair, on Metal Frames T47 does leave a lot more room for internal routing, so thats another point to take into consideration.
Your average Tour level pro can ride at 360w for an hour and sprint at 1500w....a bit more than 1/10th hp......does that change things?
@@tednruth453 How many PAYING consumers are pro level riders? You simply can't buy fitness or skills unless it's a freakin e bike or you're doped up.
Plenty of pros still use BSA bb's. When you learn souplesse (pedaling in circles) bb stiffness isn't such a big concern.
All the Japanese keirin track racers still use loose ball, square taper BBs. There's lots of money wagered in this sport.
Us fat boys have lots of torque and Power and shimano hollowtech has always coped. Shame the bonded cranks don’t stand up to 500+ watts at 60 rpm. Maybe that’s why the media want you to ride 160mm cranks and spin at 120rpm
@@tednruth453 I couldn't give two fucks what all of 200 people on the planet can do. The fuck does this have to do with the price of tea in China?
Neck breaking hello hambini today!!
Perhaps we're premature in ditching press fit. It seems like bike manufacturers have moved to T47 just when they had finally implemented processes that allow them to properly do press fit. Based on the opinions of the mechanics I know and what I've seen anecdotally, far fewer people are bringing in 2018-2022 bikes with creaking press fit BBs then there were ten years ago. Also BB86 has always been less problematic than other press fit standards, unsurprisingly that's the standard that both Giant and Canyon have stuck with.
Please don't, just let press fit die.
Correct. The least amount of parts will bring you the best solution. It´s up to the producers to meet the standards, or tolerances. Rgr
@@borano2031 Indeed. And this industry has failed miserably implementing consistent 'quality standards'. QC is a mere sticker applied to a product or a check mark on an inspection sheet. QC is an inconvenient, overpriced, bad joke in the larger bike industry. I can prove it any day I'm at work!
What is it that convinces consumers that a new BB 'standard' will solve all those problems?? The answer is marketing bullshit koolaide and the suckers born every minute who lap it up.
BSA (and other threaded standards) are tried, true and proven over numerous decades, even a century. There was never anything wrong with this standard except it cut into greedy manufacturer's profits.
Pro riders still use BSA. Bike manufacturers, (once upon a time) built BBs shells and frames much better.
Replace press fit with BSA and we're in agreement. Easy to service. Worked for decades. There's zero reason to be fucking with the rest of the bullshit.
PF execution was BAD on average (in terms of median bikes)
Threaded all the way!
I've been using a 30mm axle Lightning axle in BSA68 since 2008, plus another version in BSA73 from a few years later. There has been no issue with debonding, mis-alignment or other ills. Guess I got lucky, with both the Cervelo R3SL and the unbranded Chinese MTB frame. Lightning supplied the outboard bearing holders with a fine cross-hatch and a piece of 3mm rubber: the idea was to tighten the bearings by hand, hence avoiding over-stressing the bearing holders. That seemed to work just fine (although getting them out usually required some careful use of multigrips). There were other issues: using low strength loctite on the center-bolt to avoid it backing off during a ride, and the slightly hair raising method of breaking it loose. Real design issues, but not related to the bearing carriers.
Changing bearings was so easy, just put the carriers in the oven, wait 15 minutes and the bearings simply fell out.
Since I was young(er) and stupid(er), I used various cheap ceramic and hybrid ceramic bearings which didn't all last so well, but that was user error. In fact though, the all-time short-life champions were the no-contact NTN's I put in mid 2022, followed by riding through a flooded road during a rain storm in France. The effect of temperature difference was pretty obvious, it pulled water into the sealed sleave and removed all the bearing grease on the way. One more ride and they were rattling, so I filled them with grease, rode a couple more times and put the bikes in boxes to move to Adelaide. They didn't last too long after arrival, but they have some regular-seal NTN's now and all seems well. It's now bike n°2, behind the Winspace SLC, with the annoying PF86 BB that a certain English marketing guy called "stupid" before being hired... It still gets ridden enough, even though I'm now retired thanks to Covid, and my FTP is about half that of a current pro of my weight...
My Trek came with a T47 for Shimano which was a Praxis T47-IB (85.5 inboard bearing) which require a Trek specific tool to install. The tool made for a better fit without damaging the frame.
When the Praxis BB wore out, I replaced with one from Wheels MFG. This required a different T47 tool as the outside notches were different.
Then I replaced with a Chris King T47 which required yet another T47 tool as the outside notches were different.
However, Chris King T47 + Sram Dub AXS Red = :)
Dub BSA has worked fine last 3 years on my trail and gravel bikes with a fair amount of abuse. Neither bike came with DUB I upgraded from cartridge on a Cannondale on one and from GXP on a Specialized on another. I do periodically disassemble and inspect the bearings and cups and have replaced one or both cups if the bearings feel gritty at all. The basic bsa dub bb is fairly inexpensive to keep spares and replace considering replacement is rare. The seals are pretty effective just gotta be careful with the little blue o rings on the sleeve. No creak or noise has has been from the BB on either bike.
My bike shop had a 10 or 15 year old Felt that came in with a debonded bb cup. Hopefully, resins/manufacturing has improved since to make this issue obscure
I can already hear thousands of Chris King fans screeching wildly
Chris King buzz intensifies.
😂
Appreciate the video's 👍👍
I’m 98% into the square taper, friction shift, rim brake “everyday” bikes, but this marketing gains racing stuff is really interesting. Pretty unbelievable that they’re only finally getting around to putting the bearings back into the frame instead of continuing on hanging them out like testicles.
Thank you.
One way to avoid BB tilt/yaw deviation from crank axis is to couple the first half BB to the crank shaft just before BB thread into the BB shell and finger tight it first. Follow by the second half BB in the like manner. Once all pieces are pre aligned, we can tighten the BB together by finger then apply torque tool to finish it. This way the bearings axis and the crank axis will be complementing each other during and after the installation.
Would be really interesting to hear your thoughts on bearing size/diameter and how that affects performance and if it does at all?
As in the size of the balls themselves? I can tell you that, all else being equal, a larger ball has greater load handling capability, is less sensitive to grease viscosity, and is less prone to damage from contamination. It's like a bigger wheel going over a rock vs getting completely stopped by it and then skidding. Ideally the bigger bearing then pulverizes the debris.
That video was downright mature. You’re growing up.
In the 90's Colnago frames suffered intermittently from Galvanic corrosion in relation to the threaded bb insert. They fixed this by bonding in titanium inserts instead. A few years later they reverted back to aluminium and never suffered a relapse the aforementioned corrosion.Colnago ( like Pinarello I believe) have always used a threaded bb and don't suffer from galvanic corrosion or de-bonding on the bb interface so it must be doable to do this reliably.
I've never seen a single issue with threaded alloy BB shells in Santa Cruz' carbon frames. They're always tapped and faced correctly. I've serviced at least a couple thousand Santa Cruz MTBs and Stigmatas over a few years. These bikes are used in far harsher and dirtier conditions than road bikes will ever see.
The users of mtbs are less likely to be neat freak roadies as well.
ALL the recurring issues (not only BBs) with modern bikes stem from poor design, compromised manufacturing procedures and shit for quality control. It doesn't matter how much a bike costs either.
@@rollinrat4850 Exactly,spot on!
Great video thanks. I don't really buy into the marketing that we need the extra stiffness of a 30mm axle but the T47i standard should make it easier to create frames with ridiculous tyre clearance without horrible kludges like dropped chainstays.
Hambo , My favorite only cause i pick them up cheap is FSA 386 EVO , It comes in 24mm shaft and uses shimano type end play adjustment " basically no shims" ... i have gotten it to fit into every type frame width .
another very informative video....thanks...have to wonder why the bike world doesnt come to some agreement on a fully standardised fit...at least from some point....has be cost benefits as well as making it better in general
Thanks for great video and information, its no doubt that T47 is better choice with 30 mm axle.
¡Hola Hambini Amigos!
My bike that I ride most often is a Cannondale Super Six with Sram Red and it has been a great bike but I have replaced the bottom bracket a couple of times . I do ride my 1995 Klein Quantum Pro with Durace group and the amazing thing is , I can pop the chain of the Klein and the bottom bracket spins like the day I got it . I know Gary Klein was a MIT graduate and he definitely made some great bikes I currently own five Kleins both rode and mountain and they all have pressed fit bottom brackets and still spin perfectly . I'm not a engineering expert bye any means , so is the reason for exstronary longevity with great performance because of the bottom bracket shell being very straight and round or something else . I would love to hear what you think Hambini the great
Занимаюсь проектированием велосипедных рам и вижу большой потенциал в Т47i. В частности рекомендуем их для титановых проектов, так как прессфит в титане сделать дороже. Однако история с инструментом для монтажа такой каретки действительна актуальна. Используем его, поджимая прессом
He said, technical rubish! He is too kool!!!
im am lucky i got a got a good right bike with bb 386evo,only thing gear shitting wasnt smooth enough maybe due internal cable routing,that enough bike for me no more new bike,thanks for the video👍
Are you making bb’s for dub wide cranks? Would love one for my Scott Spark when my sram bb is done
I want you to review some of those garden tools.
My steel Tommasini doesn't have any voids at all. Even though I get dirty water on the bottom bracket, I don't have galvanic corrosion problems. I also don't worry about a carbon fiber frame breaking under me. I must say that I am paying the price. My Tomassini Fire with a steel fork does weigh 1/2 lb. more than my Trek Emonda did.
Notable to mentioned that shimano does not yet make a t47 24mm BB, however SRAM does make (sell) T47 Dub BBs.
Shimano in general has great design but they really seem to be falling behind in terms of this basic stuff. I suspect that SRAM has a much more agile development process.
Hambini can you please explain something I was being curios so long, would bb standard effect the stiffness of the bike? also would a threaded together bottom bracket improve the stiffness of the bike from pressfit bb30?
Great stuff! After watching some of your vids, I get the consensus that this is primarily an issue with carbon frames and bonded sleeves. How about small lot production of Ti frames from a moderately sized bike shop brand? Haro's Masi... to be specific. Their Incanto Ti frameset is PF. Let's face it... its name only. It will not be Faliero or even Alberto craftsmanship, but I'm pretty confident they will be aligned and circular, leading to a creak free life. Worth the gamble?
I believe the larger bike industry has well proven their incompetence. They're simply incapable or at best , challenged in the area of QC.
Honestly I only know about the nice old vintage steel handmade Masi's. I don't even know where these newer ones are made, nor anything about the Haro's current quality. I do know that years ago they build good BMX and MTB frames, but most companies have changed for the worst in the last few decades.
I simply don't trust Asian manufacturing (not including the Japanese) because I know better. I was a source inspector once upon a time! What I've seen is that Asian manufacturers often compromise in materials, procedures, QC and less skilled workers. This is how they can offer a cheaper product.
I wouldn't 'gamble' on anything! It's not worth getting stuck with junk. Remember, once you hand over your money, what you bought now potentially becomes your problem to solve. YOU own it!
You might be able to measure the PF shell if you bought a telescoping gage and a micrometer. That does require some skill though. Welded metal assemblies can distort under all that heat. If they don't ream/face the shell or machine it after welding, Id be very leery. Id want to see evidence this has been done.... therefore, the inspection in person. This negates any 'gambling'!
In high quality manufacturing, post weld machining is common to allow for the heat distortion from welding. Most especially to achieve a close toleranced assembly. Pressfit bearings REQUIRE very close manufacturing tolerances and actual QC, meaning a skilled inspector needs to measure it or at the very least a skilled assembler needs to prep (ream/face) the frame before the bearings are installed.
I can almost ASSURE you these 'frame prep' after brazing procedures were always performed by competent assemblers on those vintage Masi's I mentioned. Bicycles were once manufactured to much higher standards! Size/geometry is required by engineering standards and specs offered by bearing manufacturers. That's mechanical fact that bike manufacturers often choose to ignore these days.
I'll only purchase pricey frames when I KNOW the builder personally and can shake their hands. Then there's somebody to personally hold responsible. I've been using just a few custom frame builders for decades and I've had zero frame/bearing issues. I also ride with some of these guys now and then. They're all relatively local to me. I also support my local business and economy, bring a local business owner myself.
My best advice would be to seek a manufacturer who demonstrates pride in their work, someone with excellent work ethics and integrity. It's well worth a bit of extra money or waiting until you can save to afford it.
Pressfit shit BBs are. just one aspect that will cause me to completely ignore a potential bike purchase. The other things are INFERNAL routing, non round seatposts or ANY frame that requires proprietary parts you can only obtain from one source.
I'm really particular about my bikes and how I dispose of my own hard earned money! That's why I go custom. I always get EXACTLY what I want.
It requires research, planning and saving.
Short of that, buy a bare frame and closely inspect it BEFORE it's ever assembled. Then you may have a bit more recourse if you find an issue.
You'd be better off looking (and saving) for a used USA made Litespeed, Moots , Seven or Merlin frame or bike. You may be able to find a good deal on a rim brake frame.
Just KNOW that any decent bike shop can take the vast majority of BSA threaded frames, tap and face the shell and you'll have a BB that functions perfectly.
Do you have measurements or analysis of the stiffness of square taper shaft vs. the different hollow shaft BB standards ? How much this affects performances when you factor in the finite stiffness of the frame ?
Still using a BB90, your favorite.😆
The solution to both galvanic corrosion and bonding failure with aluminum (especially with carbon) is anodizing without sealing or dyeing, just before bonding to any other material. It's really the only solution long term. It both increases adhesive bond strength regardless of surface texture, and electrically insulates aluminum from any chance of galvanic reaction. I find starting with a smooth, even polished surface before anodizing provides the best insulation and bond. It's such an inexpensive process, it baffles me that every aluminum bike part isn't anodized.
Buen video, ¿porque no utilizan titanio para hacer las inserciones del T47 en los cuadros de carbono, y así se podría evitar la corrosión galvánica?
You manly made the case for Carbon Frames, what's your take on threaded BBs for (custom) Ti Frames ( or for that matter also Al and Steel )?
*turn on notifications for this post*
Pinarello never stopped having threaded BBs. My Pinarello bottom bracket area got gobbled by galvanic corrosion within 18 months and had to be warrantied. Then the same happened to the replacement. I do have exceptionally acidic sweat though ... .for non-freaks I wouldn't expect galvanic corrosion to trash the BB until just after the stingy two-year warranty has expired.
Would Ti be a better option than Al? It doesn't corrode, therefore avoiding galvanic corrosion and it won't de-bond either ... as I can testify after leaving a carbon seatpost in a Titanium frame for too long - they weld themselves without the need for a bonding agent.
Some boutique brands recognize the issue and put their use of Ti inserts on their marketing. When I'm paying in excess of £3k for a frame, I wouldn't mind paying an extra £100 for a Ti BB to extend the lifespan beyond two years.
You can't just look at the BB. You must also consider what is happening in the frame building process. New innovations in bonding agents may overcome problems of thermal expansion or galvanic corrosion. Also, the frames may be made using mandrels or other improvements that reduce the alignment problems or improve the threaded BB reliability over time. We may even see a comeback of lugged carbon frames made using 3d printed or other kinds of lugs, perhaps even threaded metal. Lemond has apparently developed some significant improvements in CF manufacturing that increases reliability, while at the same time reduces costs.
On my steel builds I requested a 68mm shell and t47i BB. Cups only with no sleeve. Can fit SRAM exogram short spindle bb30 cranks or standard t47 cups to use a gxp spindle.
Ever thought of reviewing the elves falath pro framset? 🤔
12:40 you can avoid water getting into the threads: ptfe tape the cups.
Hey Hambini. Love all your videos. QUESTION…I have a Pinarello Dogma F12. What are your thoughts on their BB? I really appreciate your time. Thank you
Theirs is ITA standard which is very similar to BSA. It doesn't have the reverse threaded one side, which could in theory, undo itself. They never do though
Thanks Ben. Cheers
I run the brand 15Sixteen we make ti gravel bikes and there is an noticable difference in stiffness from BSA 68 to T47 in the bottom bracket area. I'm no engineer so wont dive on the specifics on the two bb's items but we do prefer the T47 from a stiffness point of view.
When it comes to weight its nearly negligible one has a smaller bb shell and longer tubes and the other is a larger bb shell and smaller tubes. when welding its also easier to maintain square on the larger area. as well as less heat drive in a smaller area.
Time will tell on the longevity of the bb though. The frame will last for ever.
Serious question: Do any of the manufacturers pre-wrap knurled their aluminum inserts before bonding them into the CF? Or is that layer of bonding glue considered sufficient? When I build my home-builds, I wrap CF around the BBs (not just gluing in, but wet layup with compression around the BB shell, so I do not get voids as they do just gluing in...) but before I do that, I layer 2 or 3x layers of fiberglass over the shell to provide a layer of insulation between the alloy and the CF. At that point, my biggest worry visavis debonding is the potential to thermal shock and the big differences in expansion between the aluminum and the CF composite. (I'm too cheap to avoid those issues by buying Ti shells).
Just a little question what do you think about hope BB.
I feel cheated! no PEN IS WORKING, damn....
So is a press-fit bottom bracket on a TIME bike the superior option ?
Hi!
What do you think is the best BB standard if you would design it?
Would it be different for aluminium vs carbon frame?
Do you believe aluminium spindle is better because there is no possibility of galvanization or do you prefer steel spindle?
Whould you have different designed BBs for 24mm vs 30mm spindle?
Thank you
Likely an unpopular opinion, but I’d rather a technically inferior BB design that is more easily repeatable for the manufacturers who have demonstrated an inability to control the relevant tolerances. I’m inclined to think this way as the performance of an acceptable T47 BB implementation will perform better than all the fucked up press fits.
I wholly acknowledge that PF bottom brackets can be ‘repaired’, but most consumers are ignorant to that fact, or unwilling/unable. However to be fair, the consumer shouldn’t be responsible for QC and corrective action.
I have a T47 bottom bracket on a gravel bike that had galled threads despite a thorough greasing. Thankfully the manufacturer was willing to simply send me another frame, but I don’t anticipate that will be how the industry handles this moving forward.
All that said, the disbonding/corrosion issues can be avoided, I think this may result in a better quality of life for the consumer. However I remain cautiously skeptical.
I’m having an issue with my Colnago V3rs BB. I have Sram DUB power meter. My bike shop ordered a T-45 ceramic speed. It fits perfect but when they tighten the preload, it stops spinning freely. If they don’t tighten it enough, there is play in the cranks. What’s going on? They also installed a new preload adjuster. They have to put enough spacers on the drive side so the spindle doesn’t hit the screws of the front derailer. Will wavy washers help? Any recommendations and help would be appreciated. Thanks for your great videos!
So is a T47 better or worse than a pressfit (in a mass manufacturing point of view)?
What is the advantage of threaded when you are still having to insert a metal receptacle into the plastic frame? I would guess just less likely to creak? I imagine if manufactured well, then a press fit would still be the best option on a carbon frame. Speaking as someone with a Trek Emonda SLR- BB90 and, touch wood, had no issues in 2 years 😛
I think colnago was using a prior version to T47 which came out about the same time Chris king did. What is the name of the one they use on C64 and V3rs? T45? What is the difference?
Hope Stainless BSA30 still going strong, since January 2020. 1000 days of commuting, 5km one way, 120m inclination, downhill and up again, 110kg rider weight. Banshee Paradox V3 hardtail. Considering getting NTN bearings.
curious why brands, such as giant Still use Pressfit? The brand new Reign thats just came out still uses PF bottom brackets - i've owned a few giants with PF and they've never given any issues.
Can a giant tcr press it be turned into a threaded BB?
Was thinking of upgrading my 68 square taper to Hollowtech and have been advised that the frame would need re-facing at the bottom bracket. Is this really necessary? It’s a 2012 giant defy…
If you were building a custom bike. Would you spec a t47 BB? I've always used bsa and avoided sram 30mm axles.
Just curious, bsa and t47 are both bonded to carbon frame, so theyre probably equally susceptible to galvanic corrosion or bonding issues right ? Seems to me that bb386 is still the best standard because they accommodate both 24 and 30mm axles, shame not that many frames use this standard, I know BH and the earlier Merida scultura use that standard
The question is, nowadays, how many you see disbonded / bonding issue on threaded bb shell? I never see one fail regarding disbonded cheap cfrp with threaded bb. I am my self got one cheap frame on the shelf. Even it is cheap frame, shite material & quality but threaded bb in it work flawlessly.
Here is why I choose threaded bb.
In average, the smallest tolerance for cfrp that we can get fresh out of the the mold is +/-0.03mm. Need to make it small diameter then machine the pf bottom shell to accurate size.
1) In my experience dealing with Class A aerospace/advance cfrp material & process, once you machine the cfrp layer, it will damage the integrity cfrp itself and it getting worse by put stress on it.
2) Cfrp is not favorable for continuos stress + cyclic loading. 30 to 40% of it is polymer (plastic), prone to be scuff during installation.
3) For short time use in race, yes pf bb on cfrp can work flawlessly. For longevity and daily usage, pf is not ideal.
4) When you deal with pf, you don't know how tight is tight. My friend's frame, pf b.shell worn out after 2 years. Mine bb68 still strong and it is objectively tighten at 45nm.
5) Threaded bb, easy maintenance and recycleable. We can reuse the bb. Just take out worn bearings but using heat gun then put it back by using heat gun. The bearings slide in and out like butter (heat the bb, not the bearings).
3 times my recycle bb68 receives new performance bearings.
6) The bearings can be replaced, so the cost is cheap. You need only the performance bearings, cost you 50usd.
Conclusion, I will choose bb system with easy installation, easy maintenance, no damage to bb shell, lower cost and recycleable. It
Thank you for another great vid. Have you or some other party done a quality testing of e.g. crank spindle stiffness? I'm not interested in showing that an 30mm spindle is stiffer than 24mm, but something that comes down to if it really matters or not. For example, I've been trying to look at what track riders use when they appear on Eurosport, and to me some are still using square taper axles/cranks! Briefly put, If I'm correct in that, then to me the whole 30mm standard at least seems completely unnecessary performance-wise, and is therefore a marketing driven standard. And yes, I am aware that there are many other points of contact that would need to be taken into account when measuring something like deflection in the "crank area", but that's my point, has somebody done such a thing and tried to really isolate things to see what really matters/is sufficient in that area - spindle being one?
Japanese Keitin track racers are required to use old school, loose ball, square taper BBs and cranks. All bike equipment is required to meet 'NJS' approved standards.
I don't think most folks have experienced how insanely smooth a Sugino 75 crank and Superlap BB actually is.
Bikes like this are so smooth, balanced and efficient, they are nearly silent rolling on a track. All you can hear is the hiss of the tires and the sound of parting wind. Incidentally, Keirin is a big time gambling sport in Japan.
The amount of different BBs out there is too much for me to keep up with so gonna ask here. A gal I go riding with has a 2016 Giant Liv Avail with a DuraAce crank and she's got the BB creak. I replaced it some months ago (I don't remember the part number and the box is at the shop), adding blue Loctite, but she's capable of some decent wattage so it started creaking again. Is there a manufacturer that makes a threaded one or do I have to have a custom one made?
Any suggestion on an "unthreaded bb" set to fit to a trek madone with thread damage to left side on T47 type threaded shell. I need Sram bearing type if possible ... I know the product exists but that's it. Any help appreciated. Rethread tools are hugely expensive and no local shops have them. Regards
Do all the T47bb's use 6806 bearings or just the 30mm axle ones? If I get a 24mm axle T47bb do i get the smaller Shimano bearings?
Back to the integrated headset verses the no thread headset.
Industry head sets, we've had 1" steering tubes, 1-1/4", then 1-1/2". Unless you're a down hiller, you don't need a sewer pipe for a steering tube.
All is good though as I own 4 titanium bikes and will never have a need to purchase a new bike that will be obsolete once the trend of today changes to some new wizzbang must have new standard.
The industry should be going back to a 1" steerer to allow room for the cabling to be hidden in these fat aero headtubes. 🤣
Unless I missed something, I had read that one of the original design aims of T47 was to allow for a larger bottom bracket area to facilitate greater welding surface, especially for boutique ti manufacturers. Yes/no?
I can't see why it would make a difference against BSA
T47 (typically a 50-52mm OD BB shell) helps larger diameter tubes to be welded on without joint overlaps. Welding a 50+mm aluminium downtube, a 45mm steel or Ti one onto a 41mm OD BB shell can be done with some fudging, but essentially the BSA 41mm OD BB shell evolved to live with 'classic' 28.6mm and 31.8mm OD steel tubes.
The larger diameter of the T47 BB shell also increases the available offset for the downtube and chainstays from the axle centreline. Again helping reduce weld overlap and increasing weld access.
The longer T47 x 86.5 and 91.5 internal bearing shells do allow a wider spacing of the chainstay welds, aiding tyre clearance, increasing weld access and reducing joint overlaps.
As Mr. H shows, there are other issues in play with carbon frames.
In the mtb context (take the design of the Fairlight Holt for example), my understanding is the extra real estate gives the builder flexibility to also attach the ST further forward on the shell which can increase tire clearance without having to bend the ST to create it (this is nice for aesthetics, for manufacturing simplicity/speed, and also dropper posts).
So we've come full circle. Trek, Cannondale and others had big problems glueing alloy inserts into their carbon frames for BSA - before they went to press fit. I suggest they will now have exactly the same problems with T47 - as per your list in this video. Getting a metal frame gets rid of most of those issues, however. Anyone doing titanium frames with T47 yet?
You can find custom titanium builds at least
Pressfit shit was never EVER a cure for carbon frame/ alloy shell BSA Issues. Pressfit shit is very obviously a means to manufacture frames even cheaper and reap more profit.
Alloy BSA shells bonded in plastic frames is a manufacturing procedure and QC related issue.
I've serviced well over a thousand Santa Cruz carbon bikes at a dealer. They get used and abused far harder than mere road bikes. I've never seen a single issue in any of their bb shells. The only creaks I've ever heard on a Santa Cruz were from worn out bb bearings, which are changed out in maybe 5 minutes. It takes longer just to gather the freakin tools!
Clearly it's possible to do this in a reliable manner. But that might cut into many of these bike company's profits. What makes anyone believe they'll improve with T47?
How many bb freakin 'STANDARDS' are there now anyways?? I'm a pro mechanic and I need a big wall chart to figure out all these freakin 'standards'. 🤣
Ask any experienced mechanic what they'd prefer to wrench on or buy themselves....
If I put a T47 or any threaded bottom bracket in a titanium frame, is galvanic corrosion a problem? And what is best to stop it, copper/copaslip, anti seize/assembly paste, or bearing grease?
Can you please advise which is better for a titanium frame with Ultegra Di2, BSA threaded BB shell or T47 treaded BB shell? Is it worthy to "upgrade" for T47 BB shell when selecting titanium frame?
Question: on a more generic view, if we stuck to steel, 24 mm axles, would many of these bearing/clearance/tolerance issues improve? I haven't bought a crankset in a couple of years but I deliberately avoided a 30 mm axle on my last build because all the compatible BBs seemed like they were bodging a larger axle where there is no reasonable way to do it - either undersized bearings, very thin walls, low tool engagement or a combination thereof.
I also don't like aluminium axle faces rubbing on the steel bearings, but that's just me.
The only real advantage a 30 mm aluminum crank spindle has over a 24 mm steel one is light weight. Actually getting it to work on a bicycle and its bearings though is a whole 'nother story, and you've pretty much enumerated all the arguments for steel/against aluminum.
Shimano has rightly taken flak for their bonded crank arms coming apart, but their core Hollowtech II crank spindle design is pretty darn solid. For best results one could just stick with a 105 R7000 crank, or one of the non-series units (FC-R510, FC-R520) if weight isn't as much of a concern.
@@TypeVertigo
“30mm aluminium spindle is lighter’.
That’s the marketing front.
Manufacturers love aluminium spindle because it’s easier to machine and easier to form, more or less, to a similar weight as a shimano 24mm spindle.
Look around, there’s no single manufacturer makes 24mm spindle as light as shimano, including Rotor 24mm Aldhu track spindle (there should be someone weighing Aldhu spindle on yt)
Hello hambini, just a random question, what are youre thoughts on the good ol square tapered bottom brackets?
noting wrong with them
@@Hambini and Loonation. I have one on my Simoncini cycle its12 years old. Only one fitted since ownership. The orginal campagnolo failed after a couple of years. Mayvbe the local bike shop did not fit it correctly. For me it Works fine.
I'm having a problem getting a T47a right now for my factor ostro, is it possible to use t47 internal and external, to fit my frame?
So out of the existing BBs, past or present, and assuming manufacturing stays how it is now, what's "best" for the average Joe to want on his bike?
Part 2, if you made a new standard, and it was made to tight standards, as were the frames, what would it be?
Curious if they'd be the same or not. Also curious if they'd come with a complimentary pen.
BSA. Easy to work on, spare parts cheap and available as well as counterfeit options.
Even a 16mm axle is stiff enough for 99% of riders, you don't need 24 or 30mm unless you actual race crits
@@janeblogs324 True. The best part of threaded bb, it is recyclable.
This is my experience on cfrp and my thought about it.
It is easy to follow tolerance for metal product, however the cfrp is not the case. In average, the smallest tolerance for cfrp that we can get fresh out of the the mold is +0.03mm and above. So we need to machine the pf bottom shell to accurate size.
1) In my experience dealing with aerospace cfrp, once you machine the cfrp layer, it will damage the integrity cfrp itself and it getting worse by put stress on it.
2) Cfrp is not favorable for continuos, 24/7 stress (pf) + cyclic loading. 30 to 40% of it is polymer (plastic), prone to be scuff during installation.
3) For short time use in race, yes pf bb on cfrp can work flawlessly. For longevity and daily usage, pf is not ideal.
4) When you deal with pf, you don't know how tight is tight. My friend's frame, pf b.shell worn out after 2 years. Mine bb68 still strong and it is objectively tighten at 45nm.
5) Threaded bb, easy maintenance and recyclable. We can reuse the bb. Just take out worn bearings but using heat gun then put it back by using heat gun. The bearings slide in and out like butter (heat the bb, not the bearings).
3 times me recycle bb68 & receives new performance bearings.
6) The bearings can be replaced, so the cost is cheap. You need only the performance bearings, cost you 50usd.
Conclusion, I will choose bb system with easy installation, objectively tighten at 45nm, easy maintenance, no damage to bb shell, low cost and recyclable.
What is the thread specification exactly? If I have to tap an insert to fit a T47 bottom bracket, what would be the major and minor diameters of the thread and the thread profile?
Give me a gas pipe steel frame from the 1980s and a square tapered bottom bracket any day of the week
Seeing my hairdresser tomorrow. Might ask for a t47 69
@hambini I assume t47 thread established directly in titanium frame shouldn't face these problems?
You will still get galvanic corrosion