Issue link: http://read.dmtmag.com/i/34501
STATIC AND LOW SPEED LOAD AND PRESSURE COEFFICIENTS Do not exceed loads or air pressure limits of the wheel or rim without permission of the component manufacturer. Exceeding the legal speed limit is neither recommended nor endorsed. TRA (THE TIRE AND RIM ASSOCIATION, INC.) STANDARDS (These tables apply to bias ply (diagonal) truck/bus tires used on improved surfaces only and do not apply to off- road tires. Consult rim/wheel manufacturer for rim/wheel load and inflation capacities.) A. METRIC AND WIDE BASE DIAGONAL (BIAS) PLY TIRES The service load and minimum (cold) inflation must comply with the following limitations unless a speed restriction is indicated on the tire.* Speed Range (mph) 71 thru 75 (1) 66 thru 70 (1) 51 thru 65 41 thru 50 31 thru 40 21 thru 30 11 thru 20 6 thru 10 2.6 thru 5 Creep thru 2.5 Creep (2) Stationary % Load Change -12% -4% None +7% +9% +12% +17% +25% +45% +55% +75% +105% Pressure Change +10 psi +10 psi No increase No increase No increase No increase No increase No increase No increase No increase +10 psi +10 psi Inflation B. CONVENTIONAL DIAGONAL (BIAS) PLY TIRES The service load and minimum (cold) inflation must comply with the following limitations unless a speed restriction is indicated on the tire.* Speed Range (mph) 71 thru 75 (1) 66 thru 70 (1) 51 thru 65 41 thru 50 31 thru 40 21 thru 30 11 thru 20 6 thru 10 (2) 2.6 thru 5 (2) Creep thru 2.5 (2) Creep (2,3) Stationary (2) % Load Change -12% -4% None +9% +16% +24% +32% +60% +85% +115% +160% +210% (1) These load and inflation changes are only required when exceeding the tire manufacture’s rated speed for the tire. (2) Apply these increases to Dual Loads and Inflation Pressures. (3) Creep – Motion for not over 200 feet in a 30-minute period. Note 1: The inflation pressures shown in the referenced tables are minimum cold pressures for the various loads listed. Higher pressures should be used as follows: A. When required by the above speed/load table. B. When higher pressures are desirable to obtain improved operating performance. For speeds above 20 mph, the combined increases of A and B should not exceed 20 psi above the inflation specified for the maximum load of the tire. Note 2: Load limits at various speeds for: Tires used in highway service at restricted speed. Mining and logging tires used in intermittent highway service. *Exceeding the legal speed limit is neither recommended nor endorsed. Pressure Change +10 psi +10 psi No increase No increase No increase No increase No increase +10 psi +10 psi +10 psi +20 psi +20 psi Inflation 92 Section Seven: Diagonal (Bias or Cross) Ply and Tube-Type