Tires and wheels -> Glossary of tire and loading terminology for Your Volkswagen Jetta 4 Door Sixth Generation (2011-2018)

WARNING  
Using the wrong snow chains or installing snow chains improperly can cause accidents and  
severe personal injuries.  
Always use the proper snow chains.  
Follow the installation instructions provided by the snow chain manufacturer.  
Never exceed the permissible speed limit when driving with snow chains.  
NOTICE  
Remove snow chains when roads are free of snow. Otherwise, the chains can damage the  
tires, impair vehicle handling and can be quickly worn down.  
Snow chains can scratch or damage wheel rims if they have direct contact with the rims.  
Volkswagen recommends using coated snow chains.  
Glossary of tire and loading terminology  
Please first read and note the introductory information and heed the WARNINGS  
Accessory weight  
The combined weight (in excess of those standard items which may be replaced) of automatic  
transmission, electro-mechanical power steering, power brakes, power windows, power seats, radio,  
and heater, to the extent that these items are available as factory-installed equipment (whether  
installed or not).  
Aspect ratio  
The ratio of sidewall height to tire width, expressed as a percentage. A number of 70 (0.7:1 or 70%) or  
lower indicates a low-profile tire with a shorter sidewall for improved steering response and better  
overall handling on dry pavement.  
Bead  
The part of a tire made of steel wires, wrapped or reinforced by ply cords, with the shape and structure  
to ensure proper fit to the wheel rim.  
Bead separation  
A breakdown of the bond between components in the bead.  
Carcass  
The tire structure, except tread and sidewall rubber which, when inflated, bears the load.  
Chunking  
The breaking away of pieces of the tread or sidewall.  
Cord  
The strands of material forming the plies in the tire.  
Cord separation  
The parting of cords from adjacent rubber compounds.  
Cracking  
Any parting within the tread, sidewall, or inner liner of the tire extending to cord material.  
Cold tire inflation pressure  
The tire pressure recommended by the vehicle manufacturer for a tire of a specified size that has not  
been driven for more than a couple of miles (kilometers) at low speeds in the 3 hour period before the  
tire pressure is measured or adjusted.  
Curb weight  
The weight of a motor vehicle with standard equipment including the maximum capacity of fuel, oil,  
and coolant, air conditioner, and additional weight of optional equipment.  
Extra load tire  
A tire designed to operate at higher loads and at higher inflation pressures than the corresponding  
standard tire.  
Gross Axle Weight Rating (GAWR)  
The load-carrying capacity of a single axle system, measured where the tire contacts the ground.  
Gross Vehicle Weight Rating (GVWR)  
The maximum loaded weight of the vehicle.  
Groove  
The space between 2 adjacent tread ribs.  
Load rating (code)  
The maximum load that a tire is rated to carry for a given inflation pressure. You may not find this  
information on all tires because it is not required by law.  
Maximum load rating  
The load rating for a tire at the maximum permissible inflation pressure for that tire.  
Maximum loaded vehicle weight  
The total of:  
Curb weight.  
Accessory weight.  
Vehicle capacity weight.  
Production options weight.  
Maximum (permissible) inflation pressure  
The maximum cold inflation pressure to which a tire may be inflated. Also called “maximum inflation  
pressure.”  
Normal occupant weight  
Means 150 lbs (68 kilograms) times the number of occupants seated in the vehicle up to the total  
seating capacity of your vehicle.  
Occupant distribution  
The placement of passengers in a vehicle.  
Outer diameter  
The diameter of a new, properly inflated tire.  
Overall width  
Total width measured at the exterior sidewalls of an inflated tire, including the additional width of  
labeling, decorations, or protective bands or ribs.  
Passenger car tire  
A tire intended for use on passenger cars, multipurpose passenger vehicles, and trucks, that have a  
gross vehicle weight rating (GVWR) of 10,000 pounds or less.  
Ply  
A layer of rubber-coated parallel cords.  
Ply separation  
A parting of rubber compound between adjacent plies.  
Pneumatic tire  
A mechanical device made of rubber, chemicals, fabric, and steel or other materials, that, when  
mounted on an automotive wheel, provides the traction and contains the gas or fluid that sustains the  
load.  
Production options weight  
The combined weight of installed regular production options weighing over 5 lbs (2.3 kg) more then the  
standard items they replace, and not previously considered as curb weight or accessory weight. These  
include, for example, heavy-duty brakes, ride levelers, roof rack, heavy-duty battery, and special trim.  
Radial ply tires  
A pneumatic tire in which the ply cords that extend to the beads are laid at substantially 90 degrees to  
the centerline of the tread.  
Recommended inflation pressure  
The tire pressure recommended by the vehicle manufacturer for a tire of a specified size that has not  
been driven for more than a couple of miles (kilometers) at low speeds in the 3 hour period before the  
tire pressure is measured or adjusted.  
Reinforced tire  
A tire designed to operate at higher loads and at higher inflation pressures than the corresponding  
standard tire.  
Rim  
The outer edge of a wheel upon which the tire beads are seated.  
Rim diameter  
The nominal diameter of the wheel's tire bead seating surface. If you change your wheel size, to  
wheels of a different diameter, you will have to purchase new tires to match the new wheels.  
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 . 148, Tire labeling. 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, Tread depth and tread wear indicators.  
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.