Originally Posted by
JohnDThompson
Why replace a perfectly good crank and bottom bracket? If the rings are worn, just buy new rings in the sizes you want.
I don't know if a 36T chainring would fit the old crank. If the bolt circle is the common 130mm it won't. I also wonder if the change from 39T to 36T is worth the expense. Why not get a "compact" (50/34) and get a usefully lower low gear?