I’m upgrading an early 90’s Shimano freehub from 7 to 10 speeds. The freehub is FH-HG20. I bought the deore CS-M4100 11-42T cassette. Trying to install it and the last cog doesn’t engage the freehub splines and spins freely, and the lock ring won’t engage threads. Is the hub too narrow for this cassette? I measured the hub and the space from where the gears rest to the end of the freehub is 31mm. I thought it’s hyperglide so it would be compatible. Is the FH-HG20 too old to work with this modern 10 cog cassette?
by jersey_guy_
3 Comments
Looks like you’ll need to upgrade your wheel…
Yes, that is a 7-speed-only freehub. This was the first generation of Hyperglide and, yep, they quickly moved to the 8/9/10sp length of 35mm.
Change the freehub body for a 8speed one. Check compatibility first.