Inflation Pressure Loss in Tubeless Tires—Effects of Tire Size, Service, and Construction

Abstract

Abstract Maintaining proper inflation pressure in tubeless tires, particularly radials, is critical to maximum tread wear life, durability, and minimum rolling resistance for vehicle fuel economy. This paper has discussed experimental studies of tubeless tire inflation pressure loss and how it is affected by tire size, operating pressure and temperature, and innerliner construction. Inflation pressure loss rates have been measured for varied commercial production tire constructions and sizes under static, constant temperature conditions. Pilot plant built radial passenger tires with varied innerliners have been tested for inflation loss rate, both statically and dynamically. A model equation has been developed to relate inflation pressure retention (IPR) to principal parameters of tire geometry, service and innerliner construction. Correlation of predicted air retention with actual performance is promising. A tire immersion test procedure has been employed to demonstrate air loss via migration and to study its paths. These studies indicate that properly fitted tubeless tires, free of mechanical leaks, can still have significant pressure loss via permeation; that the rate of loss increases as tire size is reduced; and that an ultra-low permeability innerliner can greatly improve tire inflation retention under static and dynamic service conditions.