What is a Pneumatic Tire or Wheel?

Pneumatic Tires Pneumatic wheels or tires are air-filled tires. The air compresses to act as a shock absorber when the wheel goes over a bump or a load is applied to the garden cart. The advantage to this tire is a smoother more cushioned ride and some advantage to "vehicle" maneuverability. Pneumatic wheels are greatly affected by temperatures just like an automobile tire. However, they are inflated through a valve and can experience "flats."

Semi-Pneumatic Tires
Semi-pneumatic tires and inserts feature molded-in air pockets, much like the air pockets in the soles of athletic shoes, providing a slightly cushioned ride. In forms ranging from polyurethane tires to inserts, semi-pneumatic tires never need air maintenance, nor will they become flat when punctured, making them truly flat-free. The important distinction, however, is that while all semi-pneumatic tires are flat-free, not all flat-free tires are semi-pneumatic. For example, solid rubber tires and carefree tires, require no air.