Originally Posted by
conor
maybe folding was the wrong word, as it implies total lateral failure. but still: the force is taken entirely by the chainring, which was not manufactured to take the force of skidding.
Not quite. If a one piece crank chainring can fail by pedaling backward, then certainly it can fail pedaling
forward. This supposed destructive force is the same, only in a different direction. After all, bike riders are capable of exerting more force on the cranks pedaling forward than back. Yet this kind of failure does not seem to happen in any repeatable way. Furthermore, One piece cranks are very common on coaster brake bikes, which depend on significant backpedaling force in order to stop. Again, the type of failure you describe does not seem to happen.
On top of this all, I've been riding a one piece crank fixie for about a year and a half. There is absolutely no sign of failure in the chainring, of all places. I weigh 225 lbs, and can be seen mashing my steel rustbucket all about West L.A. After breaking forks, handlebars, bottom brackets, chains, and even aluminum cranks, on various bikes over the years, the chainring of a one piece crank is about the last thing I'd worry about.
Originally Posted by
conor
there's a reason why se used a once piece crank in only their single speed bike. there's a reason why bike shops don't convert drafts to fixed gear.
This is news to me. I don't see why they wouldn't, except to steer a customer to a more expensive bike.