in oregon the highest allowed space behind the tires is 27" im at 30 inches off the ground and got pulled for it, put mud flaps on,
heres my write up on removables http://fullsizebronco.com/forum/showthread.php?t=140470
heres the legal of it
5) Does my vehicle need mud flaps/mud guards?
Answer: Non commercial vehicles (under 8,000 lbs.) need fenders or mud guards (mud flaps) within 27 inches of the pavement behind all wheels. Commercial vehicles need fenders or mudguards (mud flaps) within 10 inches behind all wheels. (ORS 815.180)
Fenders and mud guards (mud flaps) must cover the entire tread width of the tire(s). (ORS 815.180)
6) How far can a vehicle sit off the ground before mud flaps are required?
Answer: For a vehicle that is less than 8,000 lbs the law states: "...fenders or mudguards must extend in full width from a point on the wheels that is above and forward of the center of the tire over a point at the rear of the wheel that is not more than 27 inches above the surface of the highway." ORS 815-180 (2) (c) The issue is not how far the truck can sit off the ground so much as making sure that fenders or mud flaps are in place not more than 27 inches from the surface of the highway.
7) Where do you measure that height from, lowest point of back bumper?
Answer: As stated above, you would measure the height from the ground and make sure it is not more than 27 inches.
8) How far are tires allowed to stick out from the side of a vehicle before you must get fender flares?
Answer: A fender or mudguard must cover the complete width of the tires tread. This is in ORS 815.180 (1) (a). The fender or mudguard must also be of sufficient size and constructed so that it is capable of deflecting or arresting any dirt, mud, water or other substance that may be picked up and carried on the wheels.