Graco 119451 Semi-Pneumatic Wheel

Semi-pneumatic tires are inflated tires that are also constructed with a sturdy exterior similar to that of solid tires. Unlike the pneumatic tires that are used on other vehicles, semi-pneumatic tires are not pressurized. The air in the tire is simply trapped in the hollow cavity within the tire design. These tires are not commonly designed for performance. Semi-pneumatic tires offer a slight cushioning or suspension within their application.

If you purchase semi-pneumatic tires, you'll probably notice that they're sold as a complete wheelset including the ball bearings that are necessary for mounting. This isn't always the case but it is a very cost-effective option that makes the incorporation or replacement of semi-pneumatic tires quick and efficient. They're often mounted onto plastic wheels and can be incorporated into a design through a single-bolt set-up.

In addition to being inexpensive and relatively easy to interchange and replace, semi-pneumatic tires cannot be ruined through a simple puncture. Semi-pneumatic tires are also most often lightweight, allowing for easy transportability. When semi-pneumatic tires are sold as complete wheelsets, they're very durable. They hold tight to the wheel or rim and are very difficult to separate.