Code of Massachusetts Regulations
540 CMR - REGISTRY OF MOTOR VEHICLES
Title 540 CMR 6.00 - Alteration Of Motor Vehicle Height
Section 6.05 - Maximum Combined Mechanical and Tire Lift

(1) The maximum mechanical lift for four wheel drive motor vehicles shall be calculated by multiplying the wheel base times the wheel track, and dividing the product by a safety factor of 2200: i.e., 92" w/b x 58" w/t = 5336/2200 = 2" (maximum mechanical lift). The outside diameter of the largest tire size available from the original manufacturer as standard or optional equipment for the particular motor vehicle may also be increased up to an amount equal to maximum mechanical lift calculated.

(2) The maximum combined mechanical and tire lift shall be no greater than the sum of the maximum mechanical lift and increased tire size calculated for the particular vehicle.

(3) Reconstructed motor vehicles shall be limited to the maximum combined lift allowed for the particular chassis used, in accordance with the applicable provisions of 540 CMR 6.05(1) and (2), i.e. a vehicle having a 65" track, 105" wheel base, and an original manufacturer's door height of 21" is allowed a maximum combined lift of four inches above the original manufacturer's door height. Accordingly, the lower edge of the door, door edge line or floor panel, as stipulated in the general requirements of 540 CMR 6.00, of any unladen body mounted on such chassis may not exceed 25" above the level surface upon which the vehicle rests.

(4) In doubtful cases, or in any case where the original manufacturer's specified height is not known or available, or where a motor vehicle is assembled without using a particular body and/or chassis (i.e. homemade), the Registrar shall determine the allowable maximum height and may issue a permit authorizing the operation thereof.

(5) The Registrar shall periodically provide the specifications of approved maximum altered heights.