Correct shim size for a 7 speed cassette on a 8-9-10 spd hub

[Not the Slowest]

Hey folks

I am planning to put a 7 speed cassette onto my Open Pro Wheel which has a 8,9,10 compatable hub.

From what I read including Sheldon Brown, the size of the shim seems to be 4.5mm.
Upon my research it appears that most suppliers sell a 4mm OR 4.5mm for this conversion shim, not both.

Could I use the 4.0? Seems such a small difference and I have to order this anyway.

Thanks

Rob

[oliver1850]

An 8 speed spacer and cog are actually 4.8 mm in total thickness, 3mm spacer and 1.8 for the cog.

I didn't have a 4 mm spacer, but I had one that is 3.8 mm. On the Shimano compatible hub I tried it on, the 7 speed cassette tightened up fine. I don't know how much variance there is in freehub bodies though.

If I was running a triple crank, I'd probably go with the thicker one, just to improve the chainline in the big ring. If you want to run a 14 small cog and might have clearance issues with the frame, it would be better to use the thinnest one that will still allow the lockring to tighten up.

I think either 4 or 4.5 will probably work. If I happen to have the specific hub that you're using, I can try the 3.8 spacer on it to be certain.

[Not the Slowest]

I am pretty sure I will be using an Shimano compatable Ultegra 6600 Hub and it will be on a triple.
The RD will be used in Friction mode.

Thanks Robert

[staggerwing]

When I put it on, I measured the Wheels Manufacturing spacer to be 4.5mm.

Minor note: Whatever Shimano cassette (sorry, just don't pay too much attention to group here, as long as it is not too worn) I used at the time had several of the largest cogs riveted together, and the heads of the rivets interfered with correct seating on the spacer. A few licks of a small square file, at one third increments around the spacer, made suitable indents and all has been "hunky dory" since.

[Not the Slowest]

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