For a 3 cross wheel Spocalc suggests 261.3 260.4 for a rear 135mm FSA Phil Wood hub and 221 Mavic MTB rim. DT Swiss seems to produce even numbered length spokes. Should I buy 260 mm or 258 mm (258 assumes the spokes stretch during tensioning) spokes or both lengths.

Also Phil Wood sells the FSA in 36 deg, 40 deg, and 48 deg. I think 36 is for MTB wheels but am not sure.

I used Spocalc to determine DT Swiss spoke lengths when I built my wheels, and had to go two millimeters shorter on the rear driveside than Spocalc said; using the length specified by Spocalc, the nipples bottomed out on the threads before I could get the spokes tensioned properly. I'd suggest ordering 260 for the non-drive side and 258 for the drive side.

The "°" in Phil Wood's catalog is the symbol for the number of spoke holes, it doesn't mean degrees. 36° means the hub is drilled for 36 spokes. FSA hubs are for freewheels, FSC are for Shimano cassettes. If you're building the wheel for a cassette, you don't want the FSA hub.

Phil Wood MTB hubs are set up for Shimano cassettes (FSC), while touring hubs and road hubs are available in either FSA or FSC. The MTB FSC hubs are only available in 32° and 36°.

They're very helpful in discussing their products for different applications, so give them a call at 408 298-1540 if you have any questions.

Always round down to the next shorter spoke. Actually I buy my drive side rear at least 1 mm shorter than calculated on the DT calculator. You don't want to run out of threads, no fun at all.

Al