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BB width for Ritchey Pro CX crank???(6 posts)

BB width for Ritchey Pro CX crank???JohnG
Sep 12, 2002 6:54 AM
Anyone know what length BB I'd use for a 'Ritchey Pro CX' crank on a Colnago cross frame?? The crank is an Octalink type.

FWIW, a 111mm "square" Campy BB is barely long enough when using a Campy crank. Actually, I had a tiny bit of interference at the BB cups with this combo.

Thanks
maybe this will help, maybe notJakob
Sep 12, 2002 7:49 AM
I have a 112.5 XTR bottom bracket matched to my 175mm Ritchey Pro CX. This is on a Redline, and the chainstays are about 103mm wide at the end of the crank arms. The arm clears the chainstay by about 11mm. Hope this helps.
maybe this will help, maybe notJohnG
Sep 12, 2002 9:37 AM
Thanks a bunch!

Those #'s should give me enough info to figure out what an appropiate BB length should be.

JohnG
maybe this will help, maybe notJames_M
Sep 12, 2002 10:47 AM
This is just my opinion but you should also consider your chainline when setting the cranks up not just wether they clear or not. The cranks on all my bikes probably only have 4-5 mm of clearance between them and the chainstay to get a proper chainline. One quick check (at least on a triple) is to put the chain on the middle front ring and a middle cog on the cassete and the chain as viewed from the back should form a straight line. This really does not help you pick a BB width from scratch but it will help determine if it is the correct one. There are formulas for figuring chainline and I remember using them once but can't remember what they are. I thought most cranks came with a suggested BB width, at least it would be a starting point. The most sure way to do it is to find a bike shop in your area that is willing to let you try a few different BB widths if you agree to buy from them. You may pay a little more than mail order but if you don't get it right the first time you will be looking at return costs (not to mention having to wait for a new BB) which can add up.
one more # pleaseJohnG
Sep 15, 2002 6:13 AM
What's the chainstay width at the location of the inner ring teeth???

TIA
JohnG
tomorrow. . .Jakob
Sep 16, 2002 7:20 AM
ah! of course! i forgot that number. i'm on my road bike today, but i will post it tomorrow morning when i get to work.