zacster

Ok, I've been checking specs out all over the place. If I get an Ultegra 12-25 CS6700 10sp cassette, there will be 3 small cogs with built in 2.35 spacers, 4 cogs with 4 2.35 spacers between them, and the 3 cog single unit, with a built in spacer against the last free cog, and a 1mm spacer at the back. If I replace the 4x2.35 spacers with 4x2.54 spacers from a 9 speed, and add .2mm spacers in with the small cogs, and a .2mm spacer between the single unit and the last free cog, I come out to 38.71mm, without the last 1mm spacer at the back. That compares to the 38.8 of a Campy cassette, with maybe one gear slightly off, and 39mm of an 11sp cassette. If I put another .2mm spacer at the back I get 38.91. The only question would then be where does a Campy cassette line up, and then I'd have to adjust my last spacer accordingly.

With this arrangement only the 2nd largest cog could even potentially be out of alignment, but so slightly I doubt it would be an issue at all. And I'll be on a trainer and not out on the road so it won't matter much anyway, just don't use it. And the truth of the matter is that I probably don't have my Campy cassette tuned that closely anyway.

Now all I have to do is find .2mm spacers that fit the outside diameter of the splines. Does anybody know the diameter of them? None of the diagrams I've found show that. .2mm is pretty thin but I see them available I just need the size.

Am I thinking about all this correctly?

Edit: I just realized if I had .2mm spacers I don't need the 9 speed spacers, just add .2mm there as well to the originals. If it was this easy I'm surprised this isn't just a common kluge. Just the last 2 cogs aren't spaced correctly, and the last one is set by the limit screw anyway.