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Sample Load Calculation
Standards
Sample Load Calculation US Tire & Rim Association
NOTE THERE ARE A NUMBER OF ADDITIONAL REQUIREMENTS THAT MUST BE CONSIDERED BEFORE THE LOADS CALCULATED CAN BE APPLIED. Some of these are the max vehicle speed capability. Is the tire size new or is it already in the existing tables? Is the tire to be placed on a passenger vehicle or a multipurpose vehicel. Is the Max vehicle GVW Less than 10,000 lbs and not to be used for any new design after 1/1/05, among others. So please remember this is only a general guide to provide a partila view of the complexities involved.
For 50 series aspect ratio and above.
L=K*P**0.5*Sd**1.39*(Dr+Sd)
L = load in Kg round to nearest Load Index value for tires approved after 7/85
K = 6.67*10**-5 ( 50 through 80 series )
P = Inflation pressure in kPa
Sd = (0.34848 + 0.6497(A))*S70 (mm)
S70 is section on a 70% width rim
A = Aspect Ratio = H/S70
Dr = Rim Diameter in mm (Rim Dia * 25.4 rounded to nearest whole mm )
To convert load to pounds:
Convert rounded calculated load in full Kg to closest 1 pound
To convert Inflation to Psi
Convert kPa to closest 1 psi for intermediate pressure and to next highest psi for the Maximum pressure. (35 psi for standard load tires)
NOTE THERE ARE A NUMBER OF ADDITIONAL REQUIREMENTS THAT MUST BE CONSIDERED BEFORE THE LOADS CALCULATED CAN BE APPLIED. Some of these are the max vehicle speed capability. Is the tire size new or is it already in the existing tables? Is the tire to be placed on a passenger vehicle or a multipurpose vehicel. Is the Max vehicle GVW Less than 10,000 lbs and not to be used for any new design after 1/1/05, among others. So please remember this is only a general guide to provide a partila view of the complexities involved.
For 50 series aspect ratio and above.
L=K*P**0.5*Sd**1.39*(Dr+Sd)
L = load in Kg round to nearest Load Index value for tires approved after 7/85
K = 6.67*10**-5 ( 50 through 80 series )
P = Inflation pressure in kPa
Sd = (0.34848 + 0.6497(A))*S70 (mm)
S70 is section on a 70% width rim
A = Aspect Ratio = H/S70
Dr = Rim Diameter in mm (Rim Dia * 25.4 rounded to nearest whole mm )
To convert load to pounds:
Convert rounded calculated load in full Kg to closest 1 pound
To convert Inflation to Psi
Convert kPa to closest 1 psi for intermediate pressure and to next highest psi for the Maximum pressure. (35 psi for standard load tires)