The Rotary R501N Speed Changer HD Tire Changer offers a compact design for truck tires, bus tires and wide base tires. This tire changer is equipped with four rollers positioned on both sides of the wheel in diametrically opposite positions. According to the company, the R501N Speed Changer HD is able to dismount and mount a truck tire in 30 seconds. The maximum tire width for this tire changer is 21" and maximum diameter is 52".