I bought a trek 311 frame and fork from CL IN hopes of creating my first single speed. It came with 68mm x 118mm bb spindle(for a double). I understand to keep the chain line, I'd need to buy a shorter spindle bracket to pull the single in closer to the frame. How much should I go in? I looked on amazon for the sealed bracket replacements and the shortest they have is a 68mm x 107mm. Would that work ?