Winter Tire Testing / Snow Traction Testing


RSI’s goal is to conduct winter snow traction testing in a timely manner while providing accurate and repeatable data and ensuring confidentiality. It should be noted that RSI is certified by General Motors tire suppliers annually to meet current General Motors Winter Traction TIP requirements. The advantage of this certification to Non-GM tire suppliers is that they can be assured that RSI has met very stringent yearly calibrations requirements as determined by annual on site calibration and operation inspections in West Yellowstone, MT . In addition, RSI performs (on its own volition) recalibration following winter testing to reaffirm the stability of the equipment and electronics.
 RSI is accredited to conduct the following tests:
1.      ASTM F1805 Single Wheel Driving Traction in a Straight Line on Snow and Ice Surface
2.      General Motors Snow Traction, T94SNT.TIP
3.      Rubber Manufacturers Association “Severe Snow Conditions” Test

Test Vehicle

The test vehicle is a dedicated, instrumented, four wheel rear-wheel drive test vehicle with a specially instrumented drive axle to measure fore-aft and vertical forces acting on single driven test tire. The on-board data acquisition system and software was upgraded in the summer of 2007.    

Vehicle Measurements
Vehicle Speed
5.0 + 0.2 mph (8.0 + 0.3 kph)
Test Tire Speed
1-15 mph (2-24 kph)
Test Tire Vertical Force
600-2000 lbs (272-906 kg)
Test Tire Horizontal Force
0-2000 lbs (0-906 kg)
***Please refer to ASTM F1805 standard test method for more info. on test procedure and requirements

Test  Load / Inflation

* PLEASE REFER TO ASTM F-1805 Standard section 11.9.1 and A.5 for Test Load/Inflation calculation. If you need help in this area or have any questions with calculating the correct test conditions for your tires (whether it is for GM or Severe Snow Flake), please call or email. We are well versed in this area and can help calculate your test loads/inflations for you.  Click here for more information...


Four criteria must be met before test conditions are suitable for snow traction testing on medium pack snow, which is contained in Table A2.1 of ASTM F1805
Measurement Range
Ambient temperature
Max +38oF (+3oC)
Surface temperature
+5 to +25oF (-15 to -4oC)
SRTT tractive coefficient
Penetrometer Reading 70-80
Surface Type
medium pack snow

Control Tire Usage

Each GM client is assigned their own primary control tire at the start of each winter season, or SRTT tire (P195/75R14 Uniroyal Tiger paw Plus). The control tire is run at the beginning and end of each test matrix and every third test in between. For example, if C=control tire and T=candidate tire, a sample test matrix will look as follows:
  • C,T1,T2,C,T3,T4,C      or      C,T1,T2,C,T3,C
  • Each Candidate tire should be tested at least 3 times.