Originally Posted by
pjw77
After a little careful measuring, I think the rear dropout spacing is 120mm, not 126. (The wheel with the 7-speed freewheel did go in, but it didn't just slide right in, it needed some help.)
Steel is pretty forgiving. There's plenty of debate about the stresses involved in 'shoe-horning' a 126 into a 120-spaced rear triangle..... Personally I think if it doesn't require
serious muscle to get it in, it's fine. But for peace-of-mind, resetting is pretty easily done.
How large to you want to go with the biggest rear cog? IIRC a Cyclone GT (long-cage) can handle quite a bit of chain. And should be able to handle 7sp, regardless. Check Velobase or Sheldon Brown for the correct BB spindle length for the Sugino crankset.