Down here is Texas it's a written rule (www.dorba.org) that you DO NOT ride muddy trails. We don't ride 'em 'till they're tacky. At least those of us responsible riders don't. With our clay soil, you really can't ride muddy trails anyway. At least not unless you like to carry your bike 50 feet back to the parking lot and spend an hour cleaning the mud off before it turns to concrete!