Tesla MODEL S 2012 Owner's Manual page 194

Wheels and Tires
Snow tire A tire that attains a traction index equal to or greater than 110, compared to the ASTM
E1136-93 (re-approved 2003, incorporated by reference, see §571.5) Standard Reference Test
Tire when using the snow traction test as described in ASTM F1805-00 (incorporated by
reference, see §571.5), and that is marked with an Alpine Symbol specified in S5.5(i) on at
least one sidewall.
Test rim The rim on which a tire is fitted for testing, and may be any rim listed as appropriate for use
with that tire.
Tread The portion of a tire that comes into contact with the road.
Tread rib A tread section running around the circumference of a tire.
Tread separation The pulling away of the tread from the tire carcass.
Tread wear The projections within the principal grooves designed to give a visual indication of the
indicators (TWI) degrees of wear of the tread.
Wheel-holding The fixture used to hold the wheel and tire assembly securely during testing.
fixture
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