Rim size
Designation means rim diameter and width.
Rim type designation
The industry or manufacturer's designation for a rim by style or code.
Rim width
The nominal distance between wheel rim flanges.
Section width
The linear distance between the exteriors of the sidewalls of an inflated tire, excluding elevations due to labeling decoration, or protective bands.
Sidewall
The portion of a tire between the bead and the tread.
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 ⇒ page 174. 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 ⇒ page 169.
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.
When you take delivery of the vehicle, the Tire Pressure Monitoring System is calibrated for the factory-recommended cold tire inflation pressure for the tires on your vehicle, as shown on the label
inside the driver door ⇒ Tire inflation pressure.
x The system must be recalibrated through the Infotainment system whenever you remove and remount or change any wheel or tire on the vehicle, even if the reinstalled or replacement wheels and
tires are identical to those that were removed and even if the tire pressure does not change ⇒ Tire Pressure Monitoring System (TPMS) and recalibration through the Infotainment system.
x If you have to adjust the tire pressure on a warm tire, fill the tire with 2.0 - 4.35 psi (20 - 30 kPa)
more than the pressure specified on the tire pressure label inside the driver door ⇒ Tire inflation pressure.
x If the TPMS determines that the air pressure in at least one tire is too low, carefully check the pressure in all 4 tires with an accurate tire pressure gauge. Low tire pressure usually cannot be determined by looking at the tire. This is especially true of low-profile tires.
If you have work done on your wheels or tires, inform the workshop that the vehicle is equipped with a Tire Pressure Monitoring System (TPMS).
New tires may expand slightly the first time they are driven at high speeds, which can trigger a tire pressure warning. Remember that tire pressure can only be properly measured when the tire is
“cold” ⇒ Tire inflation pressure.
Only replace old tires with tires that have been approved by Volkswagen for your vehicle type.
Indicator light (telltale)