Classic & Vintage - Frankenbike issue and a question

I have a Suteki bicycle that I have been changing since I got it - it now has bar end shifters and I just put on a set of 700c Bontrager select wheels with an 8 speed cassette - I am still runnning the original Shimano 600 (probably 1982)deraileurs, and everything shifts fine in friction mode (which is ok) but I am having issues in the lowest (11 tooth) gear - the chain skips like crazy.

Can I fix this with my current setup, or have I exceeded the capability of the ancient deraileur?

I have a Fuji that I picked up with an Exage action deraileur set - probably from the 90's. That set is 6 speed indexed - could I use it with my new 8 speed setup instead? Woudl it work? The bar ends I have are 8 speed Shimano index or friction. I am ok with keeping them friction, but would be ok with indexed as well.

If the high range screw is all the way out and the der can't get out far enough that'd be the problem

The 6 speed indexed der should work, probably have enough range, hard to know. But the indexing will be on as far as it can go. The ratio of the rear mechs are all the same and the indexing is in the shifters. I'd try it.

I would actually suspect a worn cog and/or chain. I had a similar problem with an older bike and swapping on a new cog and chain made the problem go away. If you can, put the bike on a bike stand. If it shifts and peddles fine with no load but skips while you're riding it, then it's time for a new freewheel and/or chain.

Edit -- Well poo. should have read your post better. Probably not a worn cog if you put on an 8 speed setup. Did you also install a new chain?

I have a Suteki Mixte in my shed awaiting restoration. It's in nice shape -- just needs cleaning and TLC. Not many of them around!

I didn't put on a new chain, but the one on the bike is not that old, but was running on old cogs- maybe it has grown adjusted to those cogs. I will go ahead and try a new chain.

Oh, and my wife has a Suteki mixte as well - we have a matched pair.

I'm no expert on chains, but my understanding is chains made for the older 5 & 6 speed road bikes are different from those made for more modern 7/8 speed cogs. So, that could be your issue.

Good luck!

Get a SRAM pc48 or pc58 chain and see. Also how close it that 11t to the stays? That is a pretty tight cram in an old frame, but it could be ok. A12t may help give you a little extra clear.

It is a tight fit - new chain, no dice. I'm going to adjust so I have 7 speeds and call it a day.