Wheelchair High Pressure Tires
High pressure tires also referred to as "primos", "clinchers", and "court tires". are narrower than the everyday pneumatic tire. The tread pattern is minimal and not as deep as an everyday pneumatic. While the Shrader type air valve is the most commonly used valve in the United States, a number of the high pressure tires use the Presta valve which originated in Europe. A converter is required so that they can be filled from a conventional pump with a Shrader type fitting. High pressure tires require greater inflation, 90 - 110+psi as opposed to 65psi for the everyday tire. Many of the manufacturers anticipate these tires being used with increased wheel camber and have designed the tread to be off center so as to maintain surface contact.
- This type of tire is narrower than an everyday tire which decreases contact area with the floor (smaller footprint). The treads are fewer and shallower which decreases rolling resistance. This results in the chair becoming easier to push and rolling further per push.
- High pressure tires are commonly lighter than the standard pneumatics.
- Many users prefer to trade off the softer ride of a conventional pneumatic for the improved push-ability of the high pressure ones.
- Favored by athletes for performance reasons.
- The small volume of air at higher pressure does not afford as much shock absorption, thus it makes for a harder ride than a conventional pneumatic tire.
- The smaller "footprint" of the tire may also result in diminished traction on wet or slippery surfaces.
- Smaller shallower treads tend to wear out quicker than a conventional pneumatic when used for street use.
- May require a valve converter for inflation.