Bicycle Mechanics - BB spindle lengths
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I just aquired a new road bike from a friend which has a triple chain ring front. I am wanting to change it to a double that I have laying around and need to know if I should change to a shorter BB spindle length. I currently have a 118 with the triple. What length would be suitable for the double (older Shimano 105)? Thanks.
I don't think you can use that bottom bracket with a double. I just purchased a 105 double crank and bottom bracket, and the spindle length for the double is 109.5 mm.
12-01-06, 04:24 PM
You most likely will have to change the bb to something like a 107. The specific lenght depends on which crankset you buy.
Is it a square taper BB? Have you measured the front chain line? Nominal on a triple is 45mm. Nominal on a double is about 42mm. But if it's a square taper, it's hard to predict how a different crank set will fit.
12-01-06, 06:25 PM
If the cranks are square taper, pick up a Shimano UN-53 107mm spindle length which is proper for a double crankset.
Yes, it is a square taper. I'll look into the UN-53 107, thanks.
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