Originally Posted by
Bigbus
The Front setup is 52/36T and the rear cassette (free hub) all the gears fall apart when you remove it. Does that help? From the research I've done on the bike it seems that most of them came with a 5 spd rear for a total of 10 speeds and only the later 80's stepped up to the 12 spd which I have. With my current setup I cruise between 19 and 21 MPH (52/14) so whatever that makes my cadence. I just feel like I got more power left in my legs-- but not more speed.
It sounds like a Uniglide-
https://www.sheldonbrown.com/k7.html#uniglide
Assuming you have the screw on smallest cog- you may be able to find a smaller one on ebay etc.
Do you plan on changing your next smallest cog too, or living with a noticeably wider jump between 5 & 6?
You still haven't said what the largest cog is in the back. that can also make a difference regarding "how small" you want to go.
You have to plan your progression of cogs. If you were to go to a 12T (IF you can find one) you may have to change the 2nd cog (if you can find it)......