budopo

A couple of years ago, upgraded from a 7-speed freewheel wheelset to a 10-speed wheelset (going from Suntour Superbe Pro hubs and freewheel, which I loved but was getting old in the tooth, to Shimano RS-80). The rear derailleur and shifters (downtube) were also switched from Superbe Pro to Dura-Ace. The bike is a 1991 Davidson Impulse.

But, now I've a couple of my old wheelsets lying around that I'd like to still use, if possible (Suntour freewheels and hubs, Mavic Open4CD clinchers and Mavic GEL280 sewups). Can I use narrower spacers between the cogs and use the old freewheels with the new shifters/derailleur? I know that I'd still only have 7 cogs, not ten, and I'd likely have to add a spacer behind the freewheel to move it outward to match the step-down in the freewheel body diameter, but would it work? What thickness would I need for the spacers?

Thanks in advance.

Bill Kapaun

Sheldon Brown's Bicycle Frame and Cassette Spacing Crib Sheet

fietsbob

FWIW, Fyxation has a Kit for a 6 of 9 cassette wheels built around their hub for 120 frames (5speed) the 6th adds 6mm to axle width, (7 went in standard 6 space)
Six Fyx Conversion Kit | Fyxation
Thing is Freewheels have several stages and cog types for that stage , whether the stage width subdivides as you need is Unknown


(example) Sachs aris has a screw on outer 7th screwed into 6thscrewed onto the body which held on a few splined of one diameter ,

which in turn held on 2 more whose spline was a larger diameter ..

sun tour Winner pro similar (though not interchangeable)

hueyhoolihan

i've heard that cogs AND spacers have changed WRT to witdths during the evolution of the cassette from 7 to 11 cogs. so the spacers and cogs may well have to be changed in order to make things work properly. IMO, the job would be suited to someone that is tenaciousj, finding parts, willing to fail a few times and living with the compromises. if you try it, the job should at least keep you out of trouble for a while. good luck.

but yes, i think it's doable. i've recently built up a three speed cassette from individual spacers some single hyperglide cogs i've managed to scrounge over the years. of course, it way easy for me seeing as how i use a downtube friction shifter.

budopo

That crib sheet is just what I needed. It looks like the spacing is 1.05mm narrower, so I need to replace the Suntour 3.85mm spacers with 2.1mm spacers. I'll also need some spacers at the bottom of the cog stack so that the cogs match the step-down in freewheel diameter. I can figure that out from cog and spacer thickness, and the number of cogs at each section of freewheel. With luck, I might be able to get an 8th cog in there instead of a bunch of spacers.

In any event, it should be fairly straight forward and be minimal cost (just have to buy some spacers). I'd also have to add a spacer to get the whole cogset to line up with the derailleur jockey wheels. So, now I have to look for where to buy a bunch of spacers. Hopefully, the chain width won't be a problem with the thicker cogs.