Originally Posted by sanjosedowntown
if i went with the sun rims, FMF cranks, and isis bottom bracket. what size bb would i get?
The sun rim wheelset incorporates a Formula track hub in the back. Most track hubs place the rear cog 42mm off the bike's centerline. You want the front and rear cog to be in line with each other. Therefore you want whatever bb spindle length places your front chainring 42 mm off centre. If you get one too long, your chainring will be too far to the outside/ right; if you get one too short, your chainring will be too far to the inside/left.