Myosmith

An old wheel with a 7-speed freewheel gave up the ghost and isn't worth rebuilding. I have a similar but newer wheel that has an 8-speed cassette. If I put a 7-speed cassette with a spacer on it, can I replace the defunct wheel with the newer one and still use the current 7-speed shifter and derailleur? Everything is Shimano on both the new and the old wheels as well as the shifter and derailleur. Is the spacing the same on a 7-speed cassette as it is on a 7-speed freewheel?

FastJake

Yes, spacing is the same between Shimano 7 speed freewheel/cassette.

You can try it with the 8 speed cassette if you can get an extra click out of your shifter, the spacing between 7 and 8 is close enough that it can often work with extra careful RD adjustment.

bobotech

As far as I know, the spacing is the same. I actually have a spare 7 speed hub that I have left over from when I swapped it out for an 8 speed hub. I could use another 8 speed free hub for a project bike that I'm working on. It is easy to swap out the freehubs. Too bad we don't live closer, I would swap my 7 speed for your 8 speed.

I would say the biggest problem you will find is that the 8 speed freehub assembly is wider than the 7speed freehub. So even after you get the axle back together, the width will be wider than the old freewheel spacing. You don't want to spread an aluminum framed bike and it can be a bit of a challenge to coldset a steel frame. Then you will probably have to redish the wheel to compensate for the wider freehub. When I swapped out my 7 speed for the 8 speed, I ended up having to redish my wheel so the tire was in the centerline rather than being too close to the non-drive side of the bike.

wphamilton

I did this exact thing, and it worked perfectly. If, as bobotech mentioned, you change the cassette (from 7 to 8) on the original wheel it might not line up right but in this case you have nothing to worry about in my opinion.

Myosmith

Thanks

The wheels are both spaced for 135mm and are going into a chrome moly Trek 700 frame spaced at 132.5 so they pop right in with a very minimal flex of the rear triangles. My biggest concern was the spacing between the cogs going from freewheel to cassette as I want to keep my current 7-speed indexed shifter.

HillRider

As noted, 7-speed freewheels and 7-speed cassettes are spaced the same so your shifters and rear derailleur will work fine. You will have to adjust the rear derailleur's limit screws to match the new cassette's position on the 8/9/10-speed freehub body.

Also, you have two choices as to where the 4.5 mm spacer goes. You can install it on the freehub body beore the cassette is added but many cassettes have rivets or thin bolts holding the larger cogs together and these may interfer with the spacer so you may have to file notches in the spacer to clear their heads or remove them from the cassette. You can also install the spacer outside of the smallest cog and tighten the lockring on it. I know this works with a 13T small cog and may also with a 12T.