fun at fiftyish
Retro Guru
Hi all, I am in the process of building up a '97 Spesh FSR,it is going to have 1x7 gearing using some Trek cranks I have with a 32T chainring mounted on the inside of the spider.
The shell width of thr FSR is 73mm ,but for measuring purposes I used the original 68x114 BB (don't have a 73mm one).The chainline comes out at 52.8 mm,so I subtracted 2.5mm from the equation to compensate for "wrong" shell size,giving me 50.3mm,,,
After reading Sheldon I now have a headache
,,,I am not sure whether to use the recomended figures for a triple crankset? If I use a 114mm BB I will have the aformentioned 50.3mm chainline..Am I right to assume that a 73x110mm BB,giving me a chainline of 48.3mm is the way to go? There is plenty of clearance between the chainstays/cranks so that should not be a problem
Thank you in advance.
Mark
The shell width of thr FSR is 73mm ,but for measuring purposes I used the original 68x114 BB (don't have a 73mm one).The chainline comes out at 52.8 mm,so I subtracted 2.5mm from the equation to compensate for "wrong" shell size,giving me 50.3mm,,,
After reading Sheldon I now have a headache
,,,I am not sure whether to use the recomended figures for a triple crankset? If I use a 114mm BB I will have the aformentioned 50.3mm chainline..Am I right to assume that a 73x110mm BB,giving me a chainline of 48.3mm is the way to go? There is plenty of clearance between the chainstays/cranks so that should not be a problemThank you in advance.
Mark
