Splined BB compatability

[vandickie]

My '96 XTR cranks and drivetrain are tired and I want to upgrade to a splined system. My bb's have alway's been 68x107's. With the smallest splined bb's being 68x113 with new 8/9speed cranks, how, if at all will the chainline be affected. My frame is 20" . My 2 local shops don't know either ....

[Raymo853]

I am going to say I don't know, but know where you may be able to find out. Post this on rec.bicycles.tech. Either Andy Muzi of Yellow Jersey, Sheldon Brown of Harris Cyclery or Peter Chisholm of Vecchio's Bicicletteria may know the answer. And there are a bunch of others trolling there that may know.

http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&group=rec.bicycles.tech

[Andy in Wi]

I think isis goes as narrow as 110mm, and a dura-ace bb can go to 109.5mm (dura-ace or ultegras work with XTR, any road shimano arms, and some coda cranks)

[Dr.Spoke]

chainlines on bikes are 47.5 or 50. (or at least to function with Shimano, Sram... er any gears). It is essentially academic which length you axle you should choose for your frame - the crank arm dictates the length. XTR (M-950 series) comes in two lengths 113mm and 118mm, use the shortest you can (99.99% certain) - in your case the 113mm.
Frame size compatibilty is taken up by spacers, no need to buy the wrong size for 68 or 73. It could only be easier with the latest XTR, and lighter, stiffer, more expensive.
Just beware not to buy XT, LX, or Deore compatible BB - the splines don't fit.

[Sproket]

Chainlines area= academic research= useless information to most!
If you really want a narrower chainline with some of the 1998 generation XTR, then get the Dura-Ace BB and XTR crank, they are cut with the same splines and are interchangable