What size BB do I need?

pbt150
pbt150 Posts: 316
edited August 2009 in Road buying advice
I've just bought a new chainset, and I need to get an ISIS bottom bracket to install it. After a bit of research I'm looking at either Crank Bros or FSA Platinum Pro, but I don't know how to work out what size I need.

I've already measured the BB of my bike (68mm), but how do I work out if I need 108, 113, 118 etc for the length of the axle?
FTT
Specialized Allez
http://www.flickr.com/photos/49364032@N03/4820302085/
Steel bike http://www.flickr.com/photos/49364032@N03/4656318147

Comments

  • Smokin Joe
    Smokin Joe Posts: 2,706
    The websites of the online stores will generally have that information, otherwise your LBS should know.
  • gkerr4
    gkerr4 Posts: 3,408
    Sell the chainset on ebay and buy a Hollowtech2 type instead - ISIS is awful and you'll be replacing it every five minutes.

    The external types are easier to fit, stiffer, lighter and longer lasting - they are miles cheaper too !

    Sorry
  • Wappygixer
    Wappygixer Posts: 1,396
    Buying ISIS is probably going to be an expensive mistake.
    It may be cheap at first but wait until a few months down the line.
    In comparrison ISIS bottom brackets are as tough as cheese unless you go for the top end ones which isn't overall cost effective
    Sell it or keep it for the rings but buy something else.
  • maddog 2
    maddog 2 Posts: 8,114
    if it's a road double then probably 108

    if it's mtb then prob 113

    If it's a road triple then prob 118

    I ditto the comments above though. The SKF ones do well, but I'm not sure you can get them easily these days.
    Facts are meaningless, you can use facts to prove anything that's remotely true! - Homer

Categories