So, I'm fixing up my old 105 and Sante bikes, 6 and 7 speed. I need a chain that would work with them, anyone know what would be a good choice? I *think* the SRAM PC48 will work witht the 7 speed, but not sure about the 6 speed 105 cogs?

Yeah, 6/7/8 speed chains should all work fine with 6 or 7 speed cogs. Or you can get a 6/7 speed KMC chain: https://www.nashbar.com/profile.cfm?c...at%3A%20Chains

I use various SRAM 8-speed chains on my 7-speed bike, with no problems. They're cheap and seem to be pretty nice. (PC-48 and PC-58 are the ones I've used most often, I think.)

In theory, the PC48 through 68 series is supposed to work on 6, 7 and 8 speed bikes. When I purchased my used, 89 Nishiki Ariel about a year and a half ago, the first repair I made was to replace the old Shimano chain with a shiny new PC 68. Man that thing looked good and I really like that chain, but it skipped badly through 3 of 6 gears. A really good mechanic at the local LBS recommended going back to a Shimano HG chain. It seems he had more than one not so good experience using SRAM chains on 6 speed freewheels. Sure enough when I put the Shimano chain on, the skipping stopped. I used the PC-68 on a seven speed with no problems. I tried the SRAM on the 6 speed one more time, but the skipping returned immediately. I know the SRAM box says it will work with all 6-7-8 speeds. But my experience is, be carful with a 6 speed freewheel. I'd like to give it one more try some day with a new freewheel to see if that will make a difference.

roccobike, did you stick a new Shimano HG chain on with the 6-speed freewheel to stop the skipping? I've used SRAM 48/58/68 chains (all equal dimensions) with 5, 6, 7, and 8-speed drivetrains, all with zero problems. New chain skipping on older sprockets usually just means that the sprockets have been worn out. If you run the old chain on the old sprockets, they're both worn out and not as likely to skip. But I don't see any reason why a SRAM chain should have trouble on a 6-speed freewheel. I'm currently using a PC-48 on my commuter bike with a 5-speed freewheel (and that interface is pictured here). Works perfectly.

Oh snap

rocco:

which HG chain did you go with for the 6 speed? I didn't think Shimano even made any for 6 speed systems anymore.

Hi Tim, Yes that was a brand new, right out of the box Shimano chain. I'm well aware of the point you made about the old chain wearing together with the sprocket. My old chain was not out of spec, and I was just time replacing it with a SRAM for a little bling factor. When the problems started, I decided to purchase a new Shimano chain just to see if the freewheel was going away. But the new Shimano chain worked just fine. I tried the SRAM chain on the Nishiki again, and it immediately began skipping.
Just to be sure about this issue, I tried the SRAM chain on another six speed, my Ross 290S. I couldn't get out of the cul-de-sac without it skipping on that bike as well. I tried the same SRAM chain on two seven speed bikes. It works perfectly on seven speeds, rides quiet and shifts like a dream. I'm using that same SRAM PC 68 chain on Bianchi Campione I obtained a couple of months ago. I went on two 6 mile shake down rides and it performs perfectly.
Now to your point about the SRAM chains working on 6-speeds, I only tried one SRAM chain on my six speed bikes, if you're having success, then maybe its just that one chain. Now you've got me wondering. I have a couple of other SRAM chains, if I have time I'll experiment this weekend with one of those on the Nishiki or the Ross.

Hey wtex,
I purchased a HG 50 chain. I can't believe I saved the box from that chain for one year, but I did . The carton says "for 6 7 8 speed". So yes, Shimano makes chains that are designed to work on 6 speed bikes. It was not expensive, I think I paid $16.

Weird, weird. I'll be interested to hear if other SRAM chains do the same thing on these bikes, if you get the chance to test them.

Typically, any chain designed for 8-speed will have the same inner-plate width as chains designed for 5, 6 and 7-speed, and should be compatible with any of those. This is what's bugging me here.

I've also used KMC chains (designed for 6/7/8 speed) on 6-speed freewheels with no problems, along with SRAM.

Keep us posted if you get the chance to test this.