Bottom Bracket for Richey Logic Triple Crank
 

I'm currently using an old Ritchey Logic crank on one of my bikes. As a double this crank worked great, but now as a triple the shifting is not good. Does anyone know what length bottom bracket I should be using? Currently it has a 115mm in there.

Thanks in advance for any help you can provide.

It is more direct to measure actual chain lines, ft and rr. Or visually check the chain's angle when in the middle ring and cog(s). Minor deviations from "perfect" chain line rarely causes shifting issues. Many times it's the ring/chainstay clearance that controls the ft's chainline. How much space is there on your bike? Andy

What do you mean by "not good"? More information would be helpful But my guess is the BB length (115) had the chain line set properly for the double. Now that you have added in the 3rd (inner I assume) ring (the old Ritchey Logic's were triples) the chain line has moved outward. According to Sheldon Brown's BB/crankset table (https://www.sheldonbrown.com/bbsize.html) the BB length for the old 110/74 BCD Ritchey Logic cranks should be 122.5. That is my experience with older 110/74 BCD shimano cranksets. Sheldon also has info if your Logic crank is the comact 94/58 BCD.

Good luck getting the shifting/gearing you want.

I used to have a Sugino-made Ritchey MTB triple on a Bridgestone MB-1, which has a 68mm BB shell. I think it used a 122mm spindle BB.

Is the front derailleur suitable for a triple?

I was about to ask the same thing

The Ritchey crank pulled of my 92' Bridgestone MB-1 had a 120mm spindle which is hard to find. I plan on trying 118 and will see if that's close enough.

Cheers.