Sidewall separation
The parting of the rubber compound from the cord material in the sidewall.
Speed rating (letter code)
A standardized letter code indicating the maximum speed at which a tire is designed to be driven for
extended periods of time. The ratings range from 93 mph or 150 km/h (“P”) to 186 mph or (300 km/h)
“Y”.
The speed rating letter code, where applicable, is molded on the tire sidewall 290. You may not find
this information on all tires because it is not required by law.
Tire Pressure Monitoring System
A system that detects when at least one of a vehicle's tires is underinflated and illuminates a low tire-
pressure warning light.
Tread
The portion of a tire that normally touches the road.
Tread rib
A tread section running circumferentially around a tire.
Tread separation
Tire failure caused by the tread pulling away from the tire carcass.
Tread wear indicators (TWI)
Raised areas within the main tread grooves that show, visually, when tires are worn and near the end
of their useful life 284.
Uniform Tire Quality Grading (UTQG)
A tire information system developed by the U.S. National Highway Traffic Safety Administration
(NHTSA) that is designed to help buyers compare tires. UTQG is not a safety rating, nor is it a
guarantee that a tire will last for a certain number of miles or perform a certain way. It gives tire buyers
more information to compare with factors such as price, brand loyalty and dealer recommendations.
Under UTQG, tires are graded by the tire manufacturers in 3 areas: tread wear, traction and
temperature resistance. UTQG information is molded into the tire sidewalls.
U.S. DOT Tire Identification Number (TIN)
A tire's serial number. It begins with the letters “DOT” (“Department of Transportation”) and indicates
that the tire meets all federal standards. The next 2 numbers or letters indicate the plant where the tire
was manufactured. The last 4 numbers represent the week and year of manufacture.
For example, the numbers 1709 mean that the tire was produced in the 17th week of 2009. Any other
numbers are marketing codes used by the tire manufacturer. This information is used to help identify
affected consumers if a tire defect requires a recall.
Vehicle capacity weight
The total rated cargo, luggage and passenger load. Passenger load is 150 lbs (68 kilograms) times the
vehicle's total seating capacity (as listed on the label inside the driver door).
Vehicle maximum load on the tire
The load on an individual tire that is determined by taking each axle's share of the maximum loaded
vehicle weight (GAWR) and dividing by 2.
Vehicle normal load on the tire
The load on an individual tire that is determined by taking each axle's share of the curb weight,
accessory weight, and normal occupant weight (distributed according to the table below) and dividing
by 2.
Uniform Tire Quality Grading (UTQG): Quality grades can be found where applicable on the tire
sidewall between the tread shoulder and maximum section width. Example:
x Treadwear (number)
x Traction: AA, A, B or C
x Temperature: A, B or C
For example: Treadwear 200, Traction AA, Temperature A.
All passenger car tires must conform to Federal Safety Requirements in addition to these grades.
Treadwear
The treadwear grade is a comparative rating based on the wear rate of the tire when tested under
controlled conditions on a specified government test course.
For example, a tire graded 150 (Treadwear-value 150) would wear one-and-one-half (1 1/2) times as
well on the government course as a tire graded 100.
The relative performance of tires depends upon the actual conditions of their use, however, and may
depart significantly from the norm due to variations in driving habits, service practices and differences
in road characteristics and climate.
Traction
The traction grades from highest to lowest, are AA, A, B and C. Those grades represent the tire's
ability to stop on wet pavement as measured under controlled conditions on specified government test
surfaces of asphalt and concrete. A tire marked C may have poor traction performance ⇒ .
Temperature
The temperature grades are A (the highest), B, and C representing the tire's resistance to the
generation of heat, and its ability to dissipate heat when tested under controlled conditions on a
specified indoor laboratory test wheel.
Sustained high temperature can cause the material of the tire to degenerate and reduce tire life, and
excessive temperature can lead to sudden tire failure.
The grade C corresponds to a level of performance which all passenger car tires must meet under the
Federal Motor Vehicle Safety Standard No. 109. Grades B and A represent higher levels of
performance on the laboratory test wheel than the minimum required by law ⇒ .
WARNING
The traction grade assigned to this tire is based on straight-ahead braking traction tests, and
does not include acceleration, cornering, hydroplaning or peak traction characteristics.
WARNING
The temperature grade for this tire is established for a tire that is properly inflated and not
overloaded. Excessive speed, underinflation or excessive loading, either separately or in
combination, can cause heat buildup and possible tire failure.
Volkswagen service information
