Stop trying to guess how much your tire pressure will increase as the tire temperature increases (and struggling until the pressures come up to where you want them)! Just set the tires to your desired pressure and let these relief valves automatically vent excess pressure as you race.
Their reliability has been well proven by thousands of circle track racers from Sprint Cup on down. Features lightweight aluminum construction (only 9 grams), built-in 100 mesh filter, and an enclosed poppet for protection from dirt. They can also be locked shut for tire mounting.
To install, just drill and tap a 1/8 NPT hole in the rim near the valve stem. If your rims are too thin to tap (steel wheels, for example), just drill a 11/32 inch hole and use the (included) sealing jam nuts on the inside of the rim. The lightweight valves do not affect tire balance.
As delivered, the adjustment range is from 15 to 30 psi. Pressures from 3 to 15 psi can be obtained by changing to the (included) low-pressure springs. For pressures from 30 to 38 psi, simply install the (included) shims above the standard springs.
