The Gaither Winntec Tire Dolly incorporates two sets of wheels for easy use and good balance. The rollers are adjustable to use with tires ranging from 6.5" to 22.5" with a capacity of 500 lbs. This unit is made from heavy-duty steel, making it strong enough to handle heavy off-the-road tires as well as standard and super single truck tires. Please note that the wheels are located in the rear, therefore completely eliminating the need to lift any part of the tire/wheel assembly.