Snow Traction Test Load / Inflation Calculations


ASTM 1805 Snow Traction Test Options (refer to ASTM F-1805 standard for def.)
Note 1:  A P195/75 R14 E1136 control tire is tested at a load of 468 kgf (1031 lbf) and a pressure of 240 kPa (35 psi)
Note 2: If calculated test load exceeds load capabilities of test vehicle, it is necessary to use next lower load/pressure increment until a suitable test load/pressure are met.
Option 1 (GMW15207):
P-metric Tires:  Load = lower value of 85% of 180 kPa (26 psi) load  recommended in T&RA Yearbooks or 567 kg (1250 lbf)
                             Inflation= 240 kPa (35 psi)
LT-metric Tires:   Load= 567 kg (1250 lbf)
                              Inflation= 345 kPa (50 psi)
Note: Hard Metric Tires are tested as P-Metric unless specified otherwise.
Option 2 (RMA-Severe Snow):
Test Load = 74% of the test inflation rated load
  • SL tires determined at 240 kPa (35 psi)
  • XL tires determined at 280 kPa (41 psi)
  • LT-metric determined at 345 kPa (50 psi)
Test Inflation = same pressure used to calculate test load.
Option 3:
“The test tire loads and inflation pressures shall be any other loads and pressures required to meet the individual requirement of a specific program.”