Originally Posted by
Roasted
Along with the 68 vs 73mm part, there's also a 2nd number...
73x118
...
gahhh... How can I figure out EXACTLY which one I need?
What model crank arms do you have? The Shimano model number is usually (always?) cast or stamped into the back side of each crank arm near the pedal spindle.
Once you have the model, do some Googling to find out what length bottom bracket spindle Shimano specs for it.