My father-in-law just purchased a Schwinn Caliente that's in amazing shape for its age. It has the Shimano Positron shifters on the stem and the FFS cranks. It's my understanding that the positron has the indexing in the derailuer and not in the shifter. If this is the case, will an old-school friction thumbshifter work on it? Or do you think that some Paul Thumbies would be compatible with the shifter?

On an unrelated note, he's wanting to change it over to alloy quick-release rims. But based on the photos I've seen, I'm not sure if that will work or not. At least not without replacing the whole drivetrain. I'm not sure the bike is worth that.

Here's some photos just for kicks.

Aye! Caliente!

No, you can't use any shifter besides a Positron shifter with a Positron derailleur. The system relies on a solid wire that both pushes and pulls the derailleur to make the shift. The shifter, wire, housing, and derailleur were all specific to Positron.

There were Positron thumbshifters, though. I had one back then, and there's one on Ebay right now: https://cgi.ebay.com/ws/eBayISAPI.dll...m=270285654643 . Ignore the description- it's definitely a 5-speed shifter. I'd make sure the "cable" and housing are the right length first since they can't be shortened.

You can switch it over to aluminum rims and QR hub fairly easily. The FFS freewheel fits standard hub threads, so the only difficult part will be finding built-up 27" wheels with QR hubs. One gotcha: the FFS freewheel uses the earlier Shimano freewheel tool, which is smaller than the later Uniglide tool. Bike Tools Etc. sells them.

For about $30 I swapped out the Positron on my mom's old Schwinn Traveller with cheap thumbshifters and old Altus (I think) der's. Getting the Positron stuff off was like wrestling an octopus - I didn't want to disconnect anything until I was sure the repl. would work. Works great.

Thanks guys. He's going to leave it with me for a few weeks to tune-up. I seriously doubt it will need much other than cleaning. I may suggest going the alloy wheel route since I think he wants to keep the stock wheels in the best shape possible. That should improve braking performance quite a bit. He didn't mention a thumb shifter, I just thought it may be easier for him. We'll just let that dog lie for now. I'll throw a rack and fenders on it and he'll be in business. Thanks again.