I'd like to make my '81 Schwinn Le Tour a little spiffier....
The Bay seems loaded with uber-cheap Shimano goodies, but I don't know if a sparkly, newish 105 RD will drop into my '81 Altus set up. Shimano customer service says I need to stick with a 5 speed RD, but some here say I could be rocking a 6 speed RD with no problems.
A chain and RD are probably first up on the swap out list and then perhaps the brake calipers and pads and then levers.
I've searched a goodly bit and haven't found any info on parts compatibility/interchangeability.