Sunday, November 25, 2007

My Bontrager Wheel

Its funny how you miss little things. I took out my Bontrager Race X-lite tubulars and noticed the lacing pattern of the spokes into the hub. I then took an old Alex Rim and saw how each spoke was fitted into different slots, as opposed to the Bontrager's where two crossing spokes are laced into a single slot. Just from observation it seems as if those spokes are serving to tear apart the hub flange instead of fighting each other in normal spoking pattern. Moreover, in this low spoke wheel, the angle made between opposing spokes is so much greater (almost 180 degrees) than the Alex rims, which is less severe since its a 32 spoke wheel. Thats like two spokes trying to shear the flange from a single slot, an area with high residual stress. Ouch..

And thanks to Arthur Shapiro from RBT, we now have a picture of a failure that can happen in hubs like these, although the cause of the flange failure is being debated.

And another from RoadBikeReview.

I'm very much confused as to why a hub would be designed like this. Accident waiting to happen?

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