Ok, decided to do a separate post on this just to confirm my understanding of this after research.

Some background. I'm trying to quickly and cheaply get the Trek Pro Series I recently picked up running again. Only issue is a trashed rear wheel. Loose eyelets and badly out of true. This setup has a 7 speed Sachs freewheel setup shifted by Dura Ace shifters and a 7401 RD.

I have an unused set of Shimano 105 hubbed Mavic Open 4 CD rimmed wheels that came with my 1989 Greg Lemond Ventoux. I just checked and these wheels fit perfectly in the dropouts.

So, can I not just pick up a 7 speed cassette and 4.5mm spacer and then use this Mavic wheelset? Unless I misunderstood something it seems this should work fine but I just wanted to make sure before I order in a cassette.

So, experts, this will work fine, correct?

Thanks!

I'm a little surprised the wheel fits but yes, your plan should work. Depending on the shifters you should be able to test it with the cassette on the wheels now - maybe have to use the friction setting.

If you want indexing, you'd need a DA cassette to match the shifters.

It will work. You haven't specified whether the 105 hub has a 8 or 7 speed freehub. If 7, then you obviously don't need the spacer.

With respect to 7-speed cog spacing, it is all the same, whether it is Shimano, Campagnolo or Sachs. Dura-Ace freewheels and cassettes had the same spacing as the rest of the Shimano lines.

The incompatibility between 7/8 speed Dura-Ace shifters & derailleurs and everything else in Shimano's lineup had nothing to do with cog spacing, but it was due to the unique cable pull of the shifters and the geometry of the derailleurs. So you must match 7 speed Dura-Ace shifters and derailleurs.

Thanks all, this is as I understood it also. The wheelset I'm planning to use was an 8 speed. I've never measured it but I suspect it is 128mm because it seems a tad smaller than my other wheels. It does fit the Trek just fine though.

May be a dumb question but are you sure they aren't 7 speed? 105SC 8 speed didn't come out until '93.

Thanks, I'll never remember this. I've never had a DA bike.

Well, I took an 8 speed cassette off of them. The freehub is the transition type which was compatible with uniglide and hyperglide. This LeMond bike was a total hodgepodge of mismatched parts when I got it so the wheels may not have been original

Useful additional information...

Your freehub body then has a wider spline to allow the fitting of Hyperglide cassettes. Plus threads outboard so to allow the fitting of a Unglide cassette with the threaded small cog.

Note for when you buy a new cassette: this type of freehub will not allow a 11 tooth cog found on most cassettes these days. Which is good, because 11 and 12 tooth cogs are basically useless. If I am riding at 40mph, I'll coast.

Precisely!

I didn't even know this type hub existed until I was swapping the cassette off this freehub and noticed the "weird" threaded end.

I did order the replacement cassette, just kept it at the same 13-26 for this bike.

I like having the smaller gear on my climbing bikes for when I descend. Always trying to up my top speed and sometimes it helps to be able to spin out at a high speed to carry momentum as you tuck and go aero. But yeah, day to day riding I have no need.

Figured I'd throw up a guick shot of the freehub. Might help someone down the road researching a similar issue.



The hub itself is a Shimano FH-1056 - which shows as a 8-speed hub