stanion

I might have a chance to join a crit this weekend. Are road-plus wheels permitted (650b with 47mm tires)? That is how my bike is set up.

HTupolev

I'm not aware of any governing bodies limiting tire width in road events. UCI-sanctioned road races do require that both tires inflate to the same diameter, and that the inflated diameter be between 55cm and 70cm; your tires would satisfy those requirements.

Many governing bodies don't give a crap about this kind of stuff.

63rickert

Depends who the ref is. Most will follow the letter of the rulebook and you are in. None are going to like this.

Two problems. First is the weight of the rim and tire combination. Criteriums are about constant accelerations. Some do race on skinnies that are surprisingly heavy so you may be able to overcome this.

Bigger problem is your bike will handle completely different than any other bike in the race. Criteriums are shoulder to shoulder, with body contact. If your line is unique you are safety problem. You will be watched like a hawk. If the ref calls you out of race, it's over. Could also be over if someone racing next to you decides to take matters into their own hands. Racers are hotheads and you will be tempting them.