Maytag Bravos Quiet Series dryer belt size
Since the belt doesn't appear to be available separately at the right length, your best bet is probably to buy the kit that contains the correct length belt and the replacement  rollers.
Since you'll have new rollers, you may was well put the new ones on. You can keep the old, low mileage rollers as spares, just in case something goes wrong with one of these new ones.