List:
Here are spin test results on the tire I use on my car. The test
was done to gather safety information not otherwise available on this
tire. These results are for information and entertainment only, etc.
Many thanks to Gene and Betty Burkland (and Betty's brothers) for taking
the time and effort to do the test.
Tire: New, off the shelf, Michelin Pilot Sport 275/40 ZR 17
unshaved.
tire air pressure- 50 psi
mounted tire out of round- .006"
start circumference- 80.6875"
air temp. 70' F
test- tire held at noted RPM's for 20 seconds, then stopped and
measured. free (unloaded) spin
Spin # 1: 2,000 tire rpm radius growth 1/8" 155
mph
2,500 tire rpm radius growth
1/4" 196 mph
3,500 tire rpm radius growth
5/16" 275 mph
circumference at rest- 81"
tire psi after run- 50 psi
Spin # 2: 4,000 tire rpm radius growth 1/2" 319 mph
4,500 tire rpm radius growth 1/2" + 359
mph
circumference at rest- 81.250
tire psi after run- 50 psi
Spin # 3: 5,000 tire rpm radius growth 5/8" 403
mph (spinner operators were backing up at this point)
5,172 tire rpm tire
failure 417 mph
Notes: no shake or vibration during the test. The bead was stable on
the wheel until 200 rpm prior to failure.
parts of the tire flew 500' from the spinner which was
pretty cool to watch & we were hunting tire pieces for 30
minutes in the wheat field.
Using a 68% safety factor there is still a large margin
when running the car at 200 mph.
Rex Svoboda
631 G/MS
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