This is a Bontrager 11 speed steel freehub body off a Paradigm alloy wheel. The top part of the freehub was broken off as I was installing a new cassette, a CS-HG700-11 (105) job with a steel lockring to replace the existing 11-30 11-speed cassette. The break happened well before I hit the 40nm spec. I have a guess as to what went wrong but would like other opinions of possible scenarios so I've got more to check for. I've installed a lot of cassettes, this is the first time I've seen damage of this sort.
My suspicion is that the cassette stack was too high, resulting in just a single thread purchase when the torque started ramping up. I can think of 2 possible ways this could've happened:
- The 105 11-34 cassette is actually sized for a 10-speed freehub so it comes with a 1.85mm spacer for below the largest cog. Maybe this spacer wasn't seated correctly somehow? It's keyed though, and despite some grime on the freehub the seating surfaces do look clear enough so I'm not sure about this one.
- The smallest cog may have not been aligned correctly with the splines, making it sit proud of where it should be. I usually check this pretty closely but that small cog often doesn't grab too far down into the splines so can shift when the lockring tool and torque wrench are getting put into place.
Any other scenarios that might have caused the cassette to sit too high, or maybe my suspicion of how the damage happened is off base? I happened to have a spare freehub body from an unused backup Paradigm wheelset that I swapped in and got everything installed correctly, but any knowledge that'll help me not do this again will be appreciated!
by ubernatural
1 Comment
How many times have you torqued down on that hub body? I had a similar failure once on a stock hub on a Bianchi on the 2nd time a cassette was installed. I chalked it up to a manufacturing defect and warrantied the wheel since it failed only a month or so after purchase.