Ultegra/Dura ace Bottom Bracket?

PLuKE

I am looking at replacing my Tiagra BB, I have been thinking of an Ultegra or Dura Ace, only a few pounds between the two.

Are the re any benefits getting the Dura Ace? Better bearings/seals?

Thanks

dj58

Which model, external threaded or pressfit? If external is it this one?
http://cycle.shimano-eu.com/content/seh ... b9000.html
http://productinfo.shimano.com/#/spec/1 ... WTECH%20II)
Says new sealing/50% less drag. I'd have thought either the Ultegra or the Dura-ace would be an improvement quality wise over the Tiagra.

cswitch

just go with the ultegra, I really don't think there is any noticeable difference and you can pick ultegra for cheap as chips.

keef66

Had 105 HT2 bearings on the winter bike. When they became clicky I bought Ultegra to replace them because CRC were selling them for £11. Seem to be lasting OK.

waltdinghy

Interesting comments about the relative merits of different bottom brackets . Recent info about the possibility of a "never squeak press-fit bottom bracket from Legit Engineering " must be worth chasing up. Is it possible to change from an existing bottom bracket to a press fit, or is the trouble involved and cost implication uneconomic. Interesting to hear from someone who knows.

iron-clover

I would normally say just go with the DA model if its a couple of quid, because why not? You probably won't see much difference although some reviewers claim they last longer than the Ultegra BBs. I'll be getting one soon to replace my now wearing Ultegra BB after nearly 2 years of abuse- and I'm running a Tiagra chainset!

Just make sure the adapter is included that will allow you to use your hollowtech BB tool to install it though (apparently it is included with the BB from Wiggle and CRC)- the splines are smaller on the 9000 and 6800 BBs than the other hollowtech BBs for some reason.

taon24

Waltdinghy wrote:

Interesting comments about the relative merits of different bottom brackets . Recent info about the possibility of a "never squeak press-fit bottom bracket from Legit Engineering " must be worth chasing up. Is it possible to change from an existing bottom bracket to a press fit, or is the trouble involved and cost implication uneconomic. Interesting to hear from someone who knows.

I got the impression that threaded bottom brackets (Shimano Hollowtech 2, FSA GXP and similar) tend not to squeak because the BB cups are tightened in place. The movement of the bearings will further tighten the cups into place, and the threading will resist further turning. The bearings will eventually wear out and need replacing, but won't squeak as the cups are solidly in place.
The disadvantage of threaded is that they are 24mm axles only.

Pressfit and similar (PF30, BB30) rely on the frame and bottom bracket cups being the same size. The bottom bracket will squeak in some cases because the shell and the bearing cups are not precisely the same size and so the loading of the cups changes and these can move, both rotating within the frame as they are not bound in place and movement of the cups within the BB shell.
The advantage of Pressfit is that they have a wider shell which allows wider axles, which should be stiffer.
Many of the creak free solutions lead to threading together of the BB parts within the shell, the compression of the shell between the left and right cups or the expansion of the cups within the shell allow for greater imperfections and greater resistance to movement.

To put it simply, if it is already threaded the BB is unlikely to ever take 30mm axle cranks and you just have to stick to Hollowtech or similar. I can't see any other reason to convert to pressfit if you can thread cheaply available cups in place.
A pressfit may have creaking problems but should take any crank set with the correct adaptors. You might end up converting to threaded, but you won't need to convert to pressfit.

iPete

Can't say I've ever really noticed a difference between Shimano BB but the best upgrade I've made has been in buying a torque wrench to fit them.