How Self-inflating Tires Work

The Future of Self-inflating Tires

Michelin is working with several other companies to develop an active pressure-management system called TIPM (Tire Intelligent Pressure Management), due to be available sometime in 2005. This system has a compressor that automatically adjusts the pressure in each tire while the vehicle is in operation to compensate for leaks and slow-leak punctures. The driver will be able to adjust the pressure depending on the desired driving mode: comfort, sporty, all-terrain or over-obstacle.

There are at least two other systems in the early development stages that are oriented toward the consumer market -- the EnTire system and the Cycloid AirPump system.

The EnTire Self-Inflating Tire ­system uses a valve that pulls in air from the atmosphere. It then pumps the air into the under-inflated tire using a peristaltic-pump action. The goal is to constantly maintain a specific pressure.

The AutoPump tire-inflator system by Cycloid has a small, wheel-hub-mounted pump that is powered by the turning of the wheels. When the system's monitor detects a drop in pressure of 2 to 3 psi, it pumps air into the underinflated tire. AutoPump has a warning system that is activated when there is a puncture. 

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