Originally Posted by dddave
there was no fall involved. we don't think the tooth could have been bent before, he would have been able to feel that. we had been riding for a good 3 or 4 miles before this happened.
please post your conspiracy theories.
The teeth could have been slightly bent before, not as noticeably, obviously. Maybe it happened at a bike rack, when someone else accidentally dropped his bike on your friend's or some BMX-er wasn't paying attention and smacked a beefy platform pedal into the chainring. However it happened, if it was slightly bent in the days or hours before the ride, maybe the repeated pressure of the chain on the teeth exacerbated the problem until they were bad enough that the teeth threw the chain like that. Maybe the less-than-perfect chainline of the Steamroller helped to apply pressure in unexpected directions that encouraged the damaged tooth the bend more, combined with 3/32" chain designed to be derailed.
This is all theorizing before my morning cup of coffee, so there are probably all kinds of holes in this explanation. It makes sense to me, though.