Originally Posted by
ThermionicScott
What cassette are you using now? Lowering the gearing (by using a smaller chainring or bigger cog) actually puts more torque on the freehub, and Shimano used to have max cog ratings for some freehubs to prevent damage...
EDIT. Found a note in an old thread on the subject:
From the other thread, I like the idea of using tandem-rated parts, even though that may not be cheap. It doesn't sound like you're doing anything wrong, the parts just aren't up for it.
I'm using a SunRace 11-40t 8s cassette. Looks like I'm overloading the freehub, as they're usually intended for 34t max.
But what about 2x10s bikes with 42t cassettes and 36-22t cranks? The torque applied on then should be similar or even greater to what I'm putting on mine. The FH-T610 is listed as compatible with this setup, but it's freehub body looks similar to the FH-M430 I'm currently using. Some shops around the web even sold replacement freehubs supposedly compatible with both of then.
If only Shimano published torque spec for their freehub bodies...