Bottom Bracket Differences

[DODDY]

Hi,

Just in the process of changing to a compact crankset and noticed that the Bottom Bracket that came with it is a square taper as required, but it is 113 long. The existing Bottom Bracket is 110 long. Can I use existing BB or am I better off changing to the BB supplied (113).

I hope that made sense!

 

[fossyant]

You can, but will need to check the new chainset (chainring) doesn't foul the frame.

 

[jay clock]

If they supplied 113 then I suspect it is needed.

 

[02GF74]

assuming all is symmetrical, you are talking 1.5 mm diferrence each side.

is the BB you want available in the 110 mm size? if not, you should be able to use the 113 - the pedals and chain wheels will be futher out by 1.5 mm.

you may need to adjust the front derailluer to avoid rubbing on the chain.

 

[Crankarm]

Not sure that a 110mm square taper BB was ever made? How have you measured it or is it stated on the BB? With the current set up how far is the small ring from the chain stay? As already said an additional 1.5mm either side might mean you just have to check the chain line and adjust the front and rear deraillieurs on the drive side. Hopefully the chainset being an extra 1.5mm out won't effect changing on the chainset by the front deraillieur.

 

[Alien8]

Not sure that a 110mm square taper BB was ever made?

My ss/fixed takes a 110mm square taper BB (eg Shimano UN40) - but whether you'd find a non-single-speed chainset that takes one I don't know (although of course the OP says they have one).

 

[jpembroke]

I use a 110mm UN53 BB with my Stronglight Impact chainset so yes, 110mm definitely exists.

Anyway, I'd put the chainset on the existing BB and see what happens. I reckon it'll be fine. The stronglight one I mentioned above will work with a 107mm so I'm sure yours will be OK with a 110mm.

 

[TheDoctor]

Not sure that a 110mm square taper BB was ever made? How have you measured it or is it stated on the BB? With the current set up how far is the small ring from the chain stay? As already said an additional 1.5mm either side might mean you just have to check the chain line and adjust the front and rear deraillieurs on the drive side. Hopefully the chainset being an extra 1.5mm out won't effect changing on the chainset by the front deraillieur.

My LBS proves you wrong...

Shimano, Stronglight and Acor make them. And have done for years.