Description
Note: for a more versatile and smaller tool, check out my "Freehub measuring tool" which combines the ability to measure SRAM XD and Shimano Hyperglide freehubs!
Modern Shimano compatible freehubs come in two major varieties - 10 and 11 speed compatible. At a glance, it's nearly impossible to tell the difference between the two, so I came up with this simple tool to make it easy. Pop it on an empty freehub and if it lines up with the low step, it's a 10 speed freehub, and if it lines up with the upper step, it's 11 speed.
"10 speed" freehubs fit 8, 9, and 10 speed road cassettes as well as 11 speed MTB cassettes and the 11-34 Shimano 11 speed road cassette. They can also fit 7 speed with a spacer.
"11 speed" freehubs will fit all of the above with a spacer, or normal Shimano 11 speed road cassettes.
If the freehub is shorter than the 10 speed side on an empty freehub, you're likely looking at an old 6 or 7 speed freehub.
The dimensions of each size are marked on the tool, but this is intended for use more as a quick A/B check.