Just a clarification: I am not questioning pain tolerance, just the level of risk of riding with a serious injury. I acknowledge it's a personal decision, a cost-benefit issue. I'd probably try to ride, too, if the race was worth it. Re the pain, I can fully relate to the choice -- I ran my best 5k with a stress fracture in my fibula. (I am 100% sure that the level of pain is not comparable to a cracked hip, and neither is the risk involved.)

Re the tires, I would qualify the issue of putting an older tire at the front as dependent on the level of wear. If one is riding at speed, a blown front tire is more dangerous than a blown rear tire. Sheldon Brown would have argued for the opposite, "putting the good one up front."