Why BSA Bottom Bracket is much durable than pressfit BB?

[LeDuke]

People here are dropping $$ like it's burning a hole in their pocket, yet call a $200 part that could last several frames "expensive".


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[Calnago]

+1 if it's creaking, get it fixed but do it right.

[ms6073]

Asian open mold still offers BSA though

Yes, but from what I have read, the latest iterations are actually PF30 frames with a BSA alloy sleeve bonded in place.

Aluminum cups, angular contact bearings so they can handle larger preload and side loading, really nice ceramic bearings. But......pricey!

Even better, Enduro has introduced the TorqTite bottom bracket which uses a double threaded center sleeve and incorporates the Enduro XD-15 bearings.

[Samuel Sanchez Gonzalez]

Asian open mold still offers BSA though

Yes, but from what I have read, the latest iterations are actually PF30 frames with a BSA alloy sleeve bonded in place.

Ahah, interesting!!! Thx

[ITTY]

What surprises me is that press fit bearings are common on motorcycles and the creaking etc issues just don't happen there. If motorcycle makers can do it on multiple bearings (swing arm, shock linkage, wheels, heck even transmission and main engine bearings) why can't bicycle frame makers get a single BB shell ID on each frame correct? It just takes a reamer or a hone.

One other thing is that on motorcycle bearings there's no wave washer or adjustable preload BS. No way for the user to get it wrong. (yes I know some motorcycles like BMWs have tapered roller bearings with preload adjustment). There should be no preload on deep groove ball bearings anyhow!

Sram's GXP locates the crank laterally using the NDS bearing. That won't work with press in bearings as the bearing could move outwards from the shell... unless an outer circlip is used, which is what Klein did on their press fit BBs in the 80s.

Anyhow, given that press fits work fine on motorcycles, I think that bike frame makers are just sloppy.

But the application (bottom bracket) for bicycles encounters completely different loads. In most other cases, bearings don't have to deal with such off axis loads as what a bicycle encounters due to the pedals being ~10 cm off the axis of the bearings. This is essentially trying to "pry" the bearings out of alignment, which makes BB bearing alignment much more difficult to maintain, especially when there is no mechanism holding the bearings in the same axis of rotation. That is why these bearings make noise and bottom bracket standards that use sleeves typically don't.

I just bought a whole new frame because I'm so fed up with BB30. (and N+1 )

[kulivontot]

Dat BB beefiness doe

[russianbear]

My buddy is having this issue on this Creakndale CAAD10 recently. BB is eating bearings every 2 months.

[Chiva]

Does the torq tite bearing adapter for PF 30 increase the Q factor?

[sugarkane]

Madcows cranks tests have Found there is no extra stiffness between a BSA bb and a press fit one.
None at all.
Secondly the only real reason for them is to save on the production costs. It's around $5 per frame to produce. It's totally shit that the manufacturers have also thrown the reaponsabilty of frame tolerance on the laps of the local bikeshops and groupset manufactures. Very poor form

[glepore]

+1 .

[KLabs]

Madcows cranks tests have Found there is no extra stiffness between a BSA bb and a press fit one. None at all.

Isn't that interesting

[LeDuke]

And, yet, weren't the BB30 cranks better than all but the Claviculas in stiffness/weight?


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[madonna]

Hi guys,
Maybe we should boycott the use of pressfit BB? Let the bike manufacture knows that their innovation is causing more distress than good. With so many types of BB standard... damm.. which most of them cause creaking sound and difficult to maintain as special tools are required.

So conclusion pressfit BB serves no benefits !!!!!!!!!

[kgt]

The best technology does not always prevails. There are many complicated issues involved. But we already know that...



http://monoskop.org/images/1/1f/Bijker_ ... no_OCR.pdf

[ScuderiaDouroux]

Then you have Pinarello, which is still using a threaded BB, but it's not BSA. It's Italian threaded for God sake. Even Colnago abandoned the Italian threads in favor of English threads back in 2008. In the old days, if the bottom bracket cups weren't tight enough, the way in which the bearings turned could "unscrew" the bottom bracket of an Italian threaded bike.

Well, good thing we're not in the old days, am I right? There's no way in hell Campy UT BB cups would ever come out of Italian threads from pedalling forces alone. Those things take quite a bit of effort to loosen even with a wrench. You'd have to be seriously negligent on install to have that happen nowadays...

Long live the Italian threaded bottom bracket!