Tire and Wheel Connection - Get The Connection!

TERMS

Listed below are commonly used terms when referring to tires and wheels.

Air pressure:
The amount of air inside the tire pressing outward on each square inch of the tire; expressed in pounds per square inch (psi) or kilo Pascals (kPa), the metric designation for air pressure.

Alignment:
The state in which all wheels on a vehicle are pointed in the direction relative to the road and each other.

All Season Tires:
Tires that are designed for use on dry and wet pavement, and also provide traction in snow and ice.

Alphanumeric:
A term for describing the size of a tire in which both letters and numbers are used.

Aramid:
A synthetic fabric used in some tires that is (pound for pound) stronger than steel.

Aspect Ratio:
The relationship of a tire's height to its width.

Balance:
The state in which a tire and wheel spin with all their weight distributed equally.

Bead:
A round hoop of steel wires, wrapped or reinforced by ply cords, that is shaped to fit the rim; holds the tire onto the rim.

Bolted Bias Tire:
A pneumatic tire with a body similar to that of bias tires, but also includes two or more belts under the tread.

Belt:
A rubber coated layer of cords that is located between the plies and the tread. Cords may be made from steel, fiberglass, rayon, nylon, polyester or other fabrics.

Bias Ply Tire:
A pneumatic tire in which the plies are laid at alternate angles less than 90 degrees to the center line of the tread. Plies usually run at angles about 30-40 degrees to the center line in a criss-cross fashion.

Carcass:
The tire body beneath the tread and sidetable; also called casing.

Cold Inflation Pressure:
The amount of air pressure in a tire, measured in pounds per square inch (psi) before a tire has built up heat from driving.

Cord:
The strands of fabric forming the plies or layers of the tire. Cords may be made from fiberglass, rayon, nylon, polyester.

DOT Markings:
A code molded into the sidewall of a tire signifying that the tire is in compliance with the U.S. Department of Transportation motor vehicle safety standards. The DOT code includes an alphanumeric designator which can also identify the tires ' manufacturer, production plant, date of production and brand.

Footprint:
That portion of the tread that contacts the road.

Friction:
The force between the tires and the road surface which causes the tire to grip the road.

Groove:
The space between two adjacent tread ribs; also called tread grooves. Highway Tires: Also called summer tires; designed for wet-and-dry weather driving, but not for use on snow and ice.

Hydroplaning:
A skimming net effect caused by tires losing contact with a surface covered with water. Innerliner: The innermost layer of a tubeless tire. The innerliner prevents air from permeating through the tire.

Kilopascal (kPa):
The metric unit for air pressure. There are 6. 9 kPa's to one psi. Loaded Section Height: The height of the section of the tire that is making contact with the road.

Load Index:
An assigned number ranging from 1 to 279 that corresponds to the load carrying capacity of a tire. Maximum Inflation Pressure: The maximum air pressure to which a cold tires may be inflated; found molded onto the sidewall.

Nominal Rim Diameter:
The diameter of a tire rim, given in nearest whole numbers (e.g. 15").

Overall Diameter:
The diameter of the inflated tire, without any load.

Overall Width:
The distance between the outside of the two sidewalls, including lettering and designs.

P-Metric:
Uniform designation of tire sizes, in metric measurements originally introduced by American tire manufacturers in 1977; commonly called "P-metric series." A typical P-metric tire is P205/70R14 93S.

Plus-Sizing:
An option allowing drivers to customize their vehicle by mounting low-profile tires on wider rims of one or two inches greater diameter, usually enhancing vehicle appearance, handling and performance.

Ply:
A rubber-coated layer of fabric containing cords that run parallel to each other; extends from bead to bead and goes between be innerliner and belts or tread. Pneumatic Tire: A tire designed to be filled with air (see Tire).

PSI:
An abbreviation for pounds per square inch (psi).

Radial Ply Tire:
A type of tire with plies arranged so cords in the body run at 90 degree angles to the center line of the tread. Rim: A metal support for a tubeless tire or a tire and tube assembly upon which the tire beads are seated.

Rim Width:
Distance between the two opposite inside edges of the rim flanges.

Rolling Resistance:
The force required to keep a tire moving at a uniform speed. The lower the rolling resistance, the less energy needed to keep a tire moving.

Rotation:
The changing of tires from front to rear or from side-to-side on a vehicle according to a set pattern; provides even treadwear.

Shimmy:
Wobbling of wheels from side-to-side on a vehicle. Shimmy can be caused by a variety of factors, including improperly balanced tires, poor alignment, and bent wheels.

Shoulder:
The area of a tire where the tread and sidewall meet. Sidewall: That portion of a tire between the tread and the bead.

Sipes:
Special slits within a tread that increases wet and snow traction.

Size:
The combination of tire width, construction type, aspect ratio and rim size used in differentiating tires.

Skid:
To slip or slide on the road when tires lose their rolling grip.

Snow Tires:
Sometimes called winter tires; a special type of tire with a tread and compound that gives better traction in snow; identified by the M + S, M & S, or M/S on the sidewalls. All season tires must also include these designations on the sidewall.

Speed Rating:
An alphanumeric code (A-Z) assigned to a tire indicating the range of speeds at which the tire can carry a load under varying conditions.

Tire:
A precisely engineered assembly of rubber, chemicals, fabrics, and metal designed to provide traction, cushion road shock and carry a load under varying conditions.

Tire Designation:
An alphanumeric code molded into the sidewall of the tire that describes the tire's size, including width, aspect ratio, rim diameter, load index and speed rating. Most designations use the P-Metric system.

Traction:
The friction between the tires and the road surface; the amount of grip provided.

Tramping:
A state in which a vehicle bounces up and down abnormally.

Tread:
That portion of a tire that comes into contact with the road. It is distinguished by the design of its ribs and grooves.

Tread Rib:
The tread section that runs around the circumference of the tire, separated by the tread grooves.

Treadwear Indicator:
Narrow bands, sometimes called "wear bars," that appear across the tread of the tire when only 2/32 inch of tread remains.

Tread Width:
The width of a tire's tread. UTOGS: (Uniform Tire Quality Grading Standards) A tire information system that provides consumers with ratings (from A to C) for a tire's traction and temperature. Treadwear is normally rated from 60 to 620. Ratings are determined by tire manufacturers using government-prescribed test procedures, and are molded into the sidewall of the tire.

TREATMENT

Listed below are a few tips to prevent your tires and wheels from damage.

Balancing:
Properly balanced tires and wheels spin with all their weight distributed equally. Unbalanced tires can result in a vehicle's "Shimmying" and "Tramping" (hopping up and down). When your tires are installed, the balancing should be part of the installation procedure. You should have this checked at least once a year, or if you suspect an unbalanced tire.

Alignment:
Proper alignment ensures that all wheels on a vehicle are pointed in the optimum direction to the road and each other. If all four wheels aren't traveling in exactly the same direction, this will put a strain on your tires. You're likely to get excessive wear on one edge of each of the affected tires tread, this will also contribute to poor handling and a reduction in your fuel economy. You should have this checked by an ASE certified mechanic on an annual basis.

Rotation:
The reason you should rotate your tires is because all four tires won't wear evenly. However if you rotate your tires every 6,000 to 8,000 miles you should be able to get a more uniform wear on each tire, and you can extend the life of your tread by 20 percent. While you are getting your tires rotated it gives your mechanic a good chance to inspect your vehicle's suspension and braking systems too.

Punctures and Repairs:
If you suspect that your tires have suffered a puncture, or are losing air you should take it to your tire dealer and have it inspected internally.
Only by looking at the tire from the inside can they tell if it is safe to repair. Make sure that they use a patch or a plugpatch on your tire. Using a plug only is not considered to be a safe practice. If you are losing air do not drive too far without filling it up or you could cause severe sidewall damage which will ruin your tire beyond repair.

Cleaning and Inspecting:
It is a good idea to clean your tires with soap and water at least once a month . While this will not only give you the opportunity to remove any foreign objects that might have become lodged in your tread, it will also give you the chance to check air pressure and inspect your tires for uneven wear. Prevention is the best cure.