Been doing repairs for US colleagues here in Morocco.

Have a colleague with an old Nishiki Manitoba with triple Biopace cranks. His bottom bracket needs overhauled or replaced. He is leaning towards replacing with a cartridge type.

So I do not have to tear his bottom bracket apart to measure the spindle andkn so he can keep riding...does anyone know what spindle length he needs?

I am thinking it is a 121mm spindle for a biopace triple...anyone know for sure?

-j

You could remove the cranks and hold two straight edge rulers (or similar) across the ends of the spindle, then have a helper measure between the edges for spindle length.

Can you give us the model number of the crankset. Shimano cranks will have the model number cast into the inside of the right crankarm. The model number will generally start with FC-M followed by 3 digits.

Remove the cranks, measure the exposed spindle on both sides and the width of the bottom bracket the spindle passes through (including the cups screwed into it). Add the three figures together - done.

cny-bikeman...you are a god! Wish I had thought of that.

Cheers,
-j

Thank you, but I'm just a mechanic, which means instead of memorizing a bunch of procedures one just uses observation, logic and creativity. I have actually never done what I described, just thought of the easiest way to get to the goal.

A lot of older Shimano triples had 127mm spindles, but measure yours to make sure. Many older cranks had asymetrical spindles, ie. one side ,the chainring side, was longer.