Bottom Bracket Design and Friction Tests

[@mikehall6608]

As a mechanical engineer with more brains than money (hopefully that's the case, if not then god help me), this is the kind of content I tune-in for 🤓

[@michaelmechex]

Thank you. I've also been banging my head against a wall telling people that a well machined press fit is the obvious best choice and actually, threaded bb is the one that is flawed by design. I always get arguments from people who think they know better. Often their argument is 'well bike brands tried press fit and went back' and they're right. I wonder what those brands were thinking, I bet it's either 'this lot is too ignorant to educate, just give them what they want' or 'fixing this mistake would include admitting that we have pinched a few pennies on frames that cost thousands and it significantly decreased their quality, let's not do that' 😂

[@adamchambers7502]

it probably matters more for road cyclists, but i am almost exclusivley a mountain biker these days so to me, i dont need perfectly aligned bb cups that press fit allows because they are going to move and warp every time i huck to flat or jump (105kgs weight 6 ft 25 blob of a person) threaded works best for a lot of people i assume like me, because i can chuck a load of grease on the threads and get the cup out easily in a years time in 5 mins to thro another 20 odd quid hollowtech bb in. I very much doubt i would notice the extra pinch casued by misalignment. ive 2 kids and time to ride about once a week if even . 5 years ago ai was riding 5 days a week and in the top physical fitness of my life...maybe then id appreciate some free'er moving cranks on long arduous 6k ft elevation rides. but when youre cranking out climbs on mtb rough terrain, there are far bigger efficiency gains to be had elsewhere in technique id say vs the bb

[@edrn1842]

All 3 of my bikes have Shimano BBs. 2 of them threaded, 1 pressfit. The pressfit one is still the original stock one from 2016 and going strong at 44,000km. And this is through South East Asian weather and humidity too. I've ridden the bike through proper monsoons and have had to replace my headset & wheel bearings on more than 1 occasion, but the BB remains smooth as silk. In fact, I think the cranks may have spun smoother with time! Long live Shimano BBs!!

[@BestKiteboardingOfficial]

Praxis bb in a Chinese frame from planet x, 8 years young, popped seals, flushed and regreased twice. About 50,000 miles on it

[@johnkasza2315]

Finally, a voice of reason! The money that has gone to ceramic speed, promoted by"cycling youtube channels" as an upgrade is so stupid....Dura ace is built for professional bike racing in the rain...seals with grease that will last years with almost zero maintenance..i can buy 8 duraace bb for 1 little beaver boy BB....

[@basengelblik5199]

Fabulous video. Was considering T47 for a custom Titanium frame, but decided on pressfit now and I am modelling my own labyrinth seal cup for it. Thanks man.

[@trykpaa]

Absolutely agree. Worst thing about threaded solutions is that no 2 BB apparently use the same damn tool - I literally have a box full. For PF I have 1 tool. I have had issues related to frames and poor factory install, but generally prefer PF. My 2018 Trek is still on its factory Shimano BB after >20000km.

[@abhimawa1]

Thank you PT for the explanation. Well put out. 👍 👍.

[@paulgrimshaw8334]

Good video, more for the level of thinking that goes into the analysis. Far too many online reviews equate price and quality, rather than looking at the finer points of design and engineering tradeoffs.

[@PeakTorque]

@@paulgrimshaw8334 thank you

[@CatManDoSocial]

Great stuff, Alex. Thanks. Yes, please more of this.

[@kautzz]

omg I did not know this documentation exists (obviously it does). having a blast scrolling through it! thanks!

[@CharlieCarbsandCycling]

sponsored by Lidl. Lad's made it!

[@asmaco1]

I'm quite happy for Lidl's headquarters being very near to me. They finance a lot of educational projects and also research institutions, which the state could never equip so well. And now they extend into cycle sports as a team sponsor and also as main sponsor for the "Deutschland Tour". Of course, thank you for this very informative video, bringing the discussion down to facts.

[@wsbygt]

I´m speaking as a ~1800Km\month rider who does his own maintenance: the experience of riding a near perfect Hambini BB, makes other bikes feel like crap. If you got the money and enjoy smooth and stiff pedalling just go for it. Even if you don´t race anymore... It´s worth it!

[@adriansmith5446]

Got that Dura-ace bb, fitted to a Cube Attain GTC, in 2016. Earlier this year, I replaced the chainset, anticipating a neccesary bb replacement. A tiny bit of 'graunch' on the nds bearing, and I mean tiny. The ds bearing was smooth as silk. This bike is used year round, through Scottish Winters, and encounters the kind of conditions that resulted in the rear hub bearings seizing. Quite remarkable. When, eventually, the bb needs replaced(after another 8 years 😂), it'll be the same again please. Oh, and it's run completely silently, as it still does, with zero play, since day 1.

[@feedbackzaloop]

Finally a T-shirt more wrinkled than Si Richardson's!

[@dakalla]

I have a relatively cheap "first components" t47 bottom bracket with fully sealed bearings that spins better than any ceramic speed video i saw till now. If i "let it fall" from the top it will swing around 20 times back and forth due to the weight unbalance of the left and right crank arms. It is all about perfect alignment. "Standert Erdgeschoss" stainless steel frame with T47 BB. However on my bmc teammachine slr01 with pf86 dura ace BB, it will max spin 3 times around when i give it a good push.

[@alansheard553]

Im no mechanical engineer but i do understand structures, on that test they are effectively creating a beam supported on its end, a load applied to the other end will make it deflect. As you point out the insertion of the different material bb's will alter its stiffness. This will result in differential deflection between them all and subsequently the alignment of the BB, the exact problem that bike manufacturers should be tryi g to eliminate. In a bike the BB is supported at both ends aswell.

[@borano2031]

True. I couldn´t believe it when I first saw the splines of the T-47. Rgr

[@n.m.5723]

BB71 an Unsung Hero? you mean creak, creak, creak. Went through 1 a year in a giant frame, ever so slightly misaligned frame which would start creaking. Fixed it with a Hambini BB, which is a fix for such frame issues. Even the new BB71 had more drag I can feel, and see with spin test. Worth the money imo.

[@Hysterically-Inaccurate]

Nice video, bb86 or whatever it's called (Shimano press fit) is my fav too. The other benefit is you can have a wider BB shell which is a good for your bearings and b good for tyre clearance. Can't get my head around why anyone prefers threaded!😂

[@Ih8GoogleandApple]

Every time I see a bike build and they install the crank and have to whack it in with a mallet it kills me! Then they don’t gap the crank sufficiently and do a spin. The crank rotates 3 x 4 revolutions with ceramic BB I just cry😂

[@igglebert3261]

Thanks for this detailed explanation. My local bike mech always told me to stick with Duraace BBs but I had to try boutique 🙄 Any thoughts on why a Shimano axle corroded around one bearing? Under 9 months old, NTN bearings. I would've thought some water exposure is expected!

[@mcveyj]

Love this. Long live PF86.

[@Cynyr]

I'm hoping for a T47/BSA like setup that is basically just a short section of threads that is used to pull or push the press fit part in and out. All so that i don't need "special" tools to install or replace them. That said my cheap shimano BSA BB is now 5 or 6 years old, still works just like when i installed it.

[@Rose.Of.Hizaki]

As someone who also has a bike from 2016 and still using the same shimano BB despite putting absolute thousands of miles through it. I can breath a squeaky sigh of relief.

[@mircozelle]

would love a video about currently available square taper bbs. i read bad things about the shimano options and would like to know if those are true.

[@4466ssss4]

My InfiniteBB is just dead after 3 years on an undersized (and I think misaligned) Cannondale PF30A. I'm checking with the Cannondale warranty and if it does not work, I will try to enlarge the hole myself following Hambini nasty tutorial.

[@Skooteh]

It would be interesting if someone did a 1-piece metal BB with plastic caps where it presses into the frame. I figure that would give you the strict alignment & rigidity of solid BBs and be able to accommodate the worst of the wonky bottom bracket shells. Also, copying shimanos labyrinth seals would be prudent. Come to think of it, that sounds a lot like a shimano square taper BB...

[@schmerol]

5:10 idk maybe my english isnt good enough but i don't understand why you say there is no concentricity advice, since the geometrical tolerance (again, no idea if this is propper english😂) clearly references A (radial surface of right side ⌀41mm)

[@PeakTorque]

@@schmerol yep its sort of covered in the hole position tolerance. You are correct 👍

[@zygmuntthecacaokakistocrat6589]

Is that Hambini banging on your window and saying rude words?

[@RichChh]

😂

[@ebikescrapper3925]

Hambini will draw rude pictures on his windows with his crayons.

[@Elbrunosh]

😂😂😂😂😂

[@Yamaha_Bolt]

I asked my LBS to install a Dura-Ace BB in place of my wheels manufacturing because I have premature witness marks on the axle that are different left vs right. The mechanic said it can't be done b/c my Orbea Orca uses a 386EVO. Is there no way to do this with reducers? Would they impact the performance of the Dura-Ace BB? Thank you.

[@zdravo4]

Big like for T shirt 👍😍

[@bierowns]

What are your thoughts, if going for durability, on using xtr pf bb over da? You can just replace the spacer tube to match the inner size between bearings

[@81antiloop]

Whats the difference between the ultegra vs rhe duraace version ? Weather proofing and alight design changes?

[@timtaylor9590]

My bb90 still going strong, carbon bb with bearings.

[@JamesSmith-qs4hx]

Make Bottom brackets Great Again.

[@RichChh]

Make frames great again. BB's are fine.

[@JamesSmith-qs4hx]

@RichChh Happy MAGAday Rich..😀

[@adamchambers7502]

That bottom bracket test , they shouldn't be using a grub screw to fix it aswell as that will induce a bend in the nylon.

[@tobycolin6271]

I run Shimano press fit in my winter cx bike, hambini bb30 to Shimano converting in my canondale synapse and Shimano threaded bbs in classic bikes square ore hollowtech. depending on age. For me the preload system on hollow tech is superior to all other brands. They all run fine but all of my bikes are between 1972 and 2012

[@edmundhodgson2572]

I love shimano press fit, the perfect solution along with their preload system. Everything else is second rate.

[@adamchambers7502]

Just fyi im paused at 5:23, the shaft position tolerance given to the bore opposite datum A DOES contain a concentricity tolerance. Position tolerance enforces this. Its only if you intend concentricity to be tighter or looser than position you would call it out separately in a composite feature control frame Hopefully i dont make a twat of myself if you clarify this further on in

[@PeakTorque]

Yep the hole position tol takes care of it as you say 👍I posted a reply to another comment of someone saying the same thing.

[@adamchambers7502]

@PeakTorque keep up the great content

[@bbarber6845]

Damn, anyone check on Hambini? He might not be happy.

[@WstalSprzedKompa]

These Enduro bearings from the beginning of the video are NOT full contact seal! Enduro states so but they are not. Check it.

[@lordkambing810]

best BB for me is pressfit shimano duraace, better than those metal thread-together ceramic stuff

[@Cycle.every.day.]

Some of those really spinny bb's have have play , i'd rather have a good seal.

[@feedbackzaloop]

play/preload and seals are two separate things. You can have one of, both or neither

[@danieletognozzi7641]

I still wonder why most cassette bodies don´t seal the outer bearing properly with a similar design. Campa does not even have internal sealing, only a sealing ring on the outer part of the industrial bearing. Really bizarre and disfunctional to have some ceramic bearings in your hub if you have some exposed bearings in your cassette body.

[@antoinedoinell]

i like fancy bb's and all but if i'm running shimano cranks i'm running a shimano bb. don't care enough to deal with fit kits and washers for something that costs 8-10 times more.

[@croccofanto]

should one grese the plastic cups going inside a carbon shell?

[@Antoine_Frs]

Shimano says not to use grease or anything else. I think I’ve heard on PT or Mapdec’s channel that if your frame is really undersized and you can’t ream it for some reason, then a specific grease which is not agressive on the plastic BB can help to press it in.

[@Miraflores1990]

Who did that test?

[@RICHARD.WRIGHT1]

You did'nt mention your 5yr old friend who's married to a hairdresser.

[@ΘάνατοςΧορτοφάγος]

I dont get why bike manufacturers will use different BBs, pick one and make all your bikes the same BB

[@out_spocken]

You dont? Really?

[@Haeron93]

Aldi hates this video.

[@chrisko6439]

Using nylon for the BB test is utter nonsense. We don't ride nylon frames, do we?

[@kolokowalsky772]

Note: all tested BB, have the same nylon imitation of the BB shell. So the Shimano has the worst result anyway : )

[@PeakTorque]

@@kolokowalsky772 yes it shows that the BB shell stiffness is important. But the system stiffness of the assembly - is it stiffer than that Nylon tube? I sure hope so. The way its clamped (point load from that M12 bolt) will also deform that nylon tube quite significantly which is not what happens in a bike.

[@feedbackzaloop]

on today's episode of "testing protocols not reflecting real life scenarios"

[@kolokowalsky772]

@@PeakTorque Conclusion: the real life carbon stiffness BB shell compensates softness of the Shimano's nylon...

[@borano2031]

@@kolokowalsky772 The sleeve in a Shimano BB has nothing to do with stiffness. It´s about sealing, nothing else. Rgr

[@ΘάνατοςΧορτοφάγος]

You changed my mind on threaded to pressfit. 👌

[@lazeroth89]

You're gonna piss off a couple of australians 😂

[@willappleton]

shitfight!

[@willappleton]

75 bucks sure is some for the DCTech BB86-92 Shimano OverSize, specially when you only want the cups

[@willappleton]

i agree keep press fit, enowt

[@tommyfreckmann6857]

First!