I want to swap out my bb and cranks but I don't know how to determine the size of bb and length of spindle? Do I have to remove the old one to find out? I do know the existing one is an Isis drive. The bike is a Veloz, and I am not having any luck finding info on it, except when I bought it the shop told me it was made by Haro. The crank is a Power Pro, RPM, not really sure about that either. Any help??Tkx