Below is a list of Pneumatic Wheels manufacturers from Portland, Oregon. Pneumatic wheels are hollow tires made of rubber that contain pressurized air that aids in the absorption of vibration and shock. They are similar to vehicle tires and provide casters with smooth rolling, even on bumpy, cracked or uneven surfaces. Pneumatic tires do not damage or leave marks on any flooring. They come in many different sizes but generally have a longer width than other caster wheels.