Last question on 6 to 7 speed conversion
 

Thanks to all the help here, nearly figured this conversion out. Will use a new Shimano 7 spd freewheel with washer if needed and a new SRAM or Shimano chain. Last issue is the downtube shifters, To double check: found a pair of NOS 7 speed shifters on Ebay. Ad says they don't have bolts etc. I should be able to use the bolts etc from my 6 speed SIS, correct?

Shimano Light Action SL A500 7 s Downtube Shifters New Indexed or Friction | eBay

i know with friction you shouldn't have a problem converting from 6 to 7, not sure on the bolt though, im sure somebody here can answer your question

Thanks, I am hoping someone will be able to confirm (or not).

Anybody? Local resources for this just don't exist, so I really need to find a way to save my 4 days younger than 60 yr old knees if I want to do the local hills (and I do) . Thanks!

We're talking downtube shifters here? Try it. If they don't work, bolts are cheap.

I agree they should work, I think I have a bike around here with a look cleat screw/bolt holding the right shifter on.

If you didn't buy the chain yet checkout KMC, nice chains and may save you a few bucks.

Thank you both! Yep, downtube, and I am definitely considering a KMC chain . . .will probably go that route asap.

Afaik, the bolts (M5) used for SIS downtube shifters are interchangeable; I converted a 6sp Exage drivetrain to a 7sp 105 set up and reused the Exage bolts.

Make sure the shifters come with at least all of the basic mounting boss fittings, which can be hard to find. Suitable metric bolts should be pretty easy to scrounge -- even my local ACE Hardware has them.

KMC chains are great quality at the "X" series level.

Their Z-series chains work fine but are really low-end chains as far as manufacturing precision; ...actually hard to measure chain wear with these because there is so much link-to-link pitch variance!

One more thing is that any Shimano "Light Action" shifters should be used with corresponding "Light Action" derailers, since the helper spring in the shifter is better balanced against the return spring in the derailer. I've seen problems with mis-matched parts of this type, but have no idea if the OP's shifters are just 105 shifters or might possibly be a Light Action model.