BB alternatives

matt21

Hi all - I've got an increasingly notchy press fit bb on my Cube agree that looks like it's had its day. It's an sm fc7800. Can anyone suggest an alternative please?

Thanks in advance

dj58

Is it the O.E. BB that came with the bike? Shimano SM-BB91-41B should do the job
http://www.bike24.com/p213413.html

Take the NDS crank off and check which BB you have fitted.

Pokerface

It's not cheap, but would something like this work as an alternative: http://www.evanscycles.com/products/hop ... 2#features

Basically it's a pressfit BB that screws the two parts together to hold it in place better.

letap73

Pokerface wrote:

It's not cheap, but would something like this work as an alternative: http://www.evanscycles.com/products/hop ... 2#features

Basically it's a persist BB that screws the two parts together to hold it in place better.

Same as above:

http://bbinfinite.com/index.php?route=p ... duct_id=65

Pokerface

Or just replace with the same part you already have. It may just have worn out.

johnmiosh

The Ultegra level version works just as well.

http://www.chainreactioncycles.com/shim ... lsrc=aw.ds

arlowood

How about this as an option



Converts BB30 to standard BSA threaded unit so you can fit Hollowtech II or other external or square taper BB

http://www.ribblecycles.co.uk/sp/road-t ... 0000000000

Not expensive at £14

Pokerface

arlowood wrote:

How about this as an option



Converts BB30 to standard BSA threaded unit so you can fit Hollowtech II or other external or square taper BB

http://www.ribblecycles.co.uk/sp/road-t ... 0000000000

Not expensive at £14

I don't think this frame is BB30 though? BB86 - isn't that some random pressft size? Still runs a 24mm axle doesn't it?

simonj

BB86, uses pressfit, bit like PF30, but is for smaller Shimano type 24mm cranks not 30mm BB30. The bearings are internal so you can't convert to put bearings outside as the frame is already as wide as the crank needs - I think 86/86.5mm. You can convert the BB to take 30mm crank, but not BB30 cranks as they are too narrow 68mm (road), only BB386 type crank (or rotor) which is a hybrid with 30mm diameter, but the width of Shimano crank.

A handy reference :-

http://problemsolversbike.com/files/tec ... erence.pdf

Pokerface

simonj wrote:

BB86, uses pressfit, bit like PF30, but is for smaller Shimano type 24mm cranks not 30mm BB30. The bearings are internal so you can't convert to put bearings outside as the frame is already as wide as the crank needs - I think 86/86.5mm. You can convert the BB to take 30mm crank, but not BB30 cranks as they are too narrow 68mm (road), only BB386 type crank (or rotor) which is a hybrid with 30mm diameter, but the width of Shimano crank.

A handy reference :-

http://problemsolversbike.com/files/tec ... erence.pdf

The particular BB the OP mentioned uses external cup though. They just press into the frame in stead of screwing in.

matt21

Thanks for the responses
It should be BB91 apparently, but I've had to admit defeat this time due to a badly seized crank pinch bolt.s lbs say it'll have to be drilled out.