Abrasion
Wearing away of the tire's surface by scraping, rubbing, or impact. Basically, it's the progressive wearing down of a tire as you drive on it.
Aging
Over time, the physical and chemical properties of the rubber in a tire can deteriorate due to oxidation. This is what we call aging.
Air Pressure
The amount of air inside the tire pushing outward on every square inch. It's measured in pounds per square inch (psi) or kiloPascals (kPa) in the metric system. Having the right air pressure is crucial for your tires to perform properly.
Alignment
When all the wheels on your vehicle are pointed in the optimum direction relative to the road and each other, that's called proper alignment. It's essential for even tire wear and handling.
All-Season Tire
These tires have a tread design and tread compound that provide better traction in mud and/or snow compared to regular tires. They'll have M+S, M&S, or M/S marked on the sidewall, which means they meet the industry standards for all-season tires.
Alpha Numeric
This term refers to using a combination of letters and numbers to describe a tire's size.
Anti-Ozonant and Anti-Oxidant
These are substances added to the rubber to help delay aging caused by ozone and oxidation, respectively.
Aramid
A synthetic fabric used in some tires that's stronger than steel for its weight. It helps reinforce the tire structure.
Aspect Ratio
This number represents the relationship between a tire's sidewall height and its width. It's expressed as a percentage of the sidewall height compared to the width.
Balance
When a tire and wheel spin with their weight evenly distributed, that's called balance. Proper balance is important for a smooth ride.
Bead
The circular bundle of steel wires that helps secure the tire onto the wheel rim.
Belt
A layer of cords (steel, fiberglass, or fabric) coated in rubber that sits between the tread and the body plies. It helps reinforce the tire structure.
Belted Bias Tire and Bias Ply Tire
A belted bias tire has body plies crisscrossed at angles (like a traditional bias ply tire) but with added belts under the tread for extra reinforcement. A regular bias ply tire doesn't have those extra belts.
Bleeding a Tire
Releasing some air from the tire to reduce its pressure.
Blemish
Any surface irregularity or imperfection on the tire.
Blister
A separation or bulge in the tire's sidewall or inner lining.
Body
The main structural part of the tire, excluding the tread and sidewalls.
Bottoming
When the vehicle's body and frame hit together due to weak shock absorbers. Not good for the tires!
Bruise
Internal damage to the tire's carcass (the body plies) from an impact, without actually cutting or tearing the outer rubber.
Camber
The inward or outward tilt of the wheels from top to bottom. Too much camber can cause uneven tire wear and handling issues.
Carbon Black
A form of carbon used as an ingredient when making rubber tires.
Carcass
The main body of a tire under the tread and sidewalls. Also called the casing.
Carrying Capacity
The maximum load that a tire is designed to support under standard conditions, as determined by the Tire and Rim Association.
Casing
See Carcass.
Caster
How far forward or backward the steering axis is tilted relative to the vertical position. Proper caster angle aids in steering feel and high-speed stability.
Checking
Small cracks that develop on the tire's surface due to aging and oxidation of the rubber.
Chunking
When pieces of tread rubber tear or break away from the tire.
Circumferential Cracks
Cracks that form parallel to the beads, often in the grooves of the tread area.
Cold Inflation Pressure
The amount of air pressure in the tire measured at ambient temperature before any heat has built up from driving.
Comfort
How well the tire is able to minimize road noise, harshness, and vibrations felt by the vehicle occupants.
Cord
The strands of material (aramid, fiberglass, nylon, etc.) that form the tire's body plies or belts.
Cracking - Tread or Groove
Splits or cracks that develop in the tread grooves due to excessive strain and flexing.
Cross-Section Size
The measurement from one tire sidewall to the other, excluding any decorative ribs or lettering. Also called section width.
Crown
The central section of the tread area between the shoulders.
Crown Radius
A measurement of how curved or flat the tread area is between the shoulders, expressed as a percentage.
Curb Scuffing
When the tire's shoulders or sidewalls get scraped or abraded by rubbing against a curb.
Curing
The process of heating and treating the rubber compound to convert it into its final solid, heat-resistant state. Vulcanization is the curing process that uses heat.
Deflection
How much the loaded radius of the tire is smaller than its free radius (unloaded).
DOT Number
A code molded into the tire sidewall that signifies it meets Department of Transportation safety standards. It can identify the manufacturer, plant, date, and brand.
Directional Tread
A tread design meant to roll in one specific direction for optimal performance.
Dual Kissing
When the tires on a dual (double) setup rub together due to inadequate spacing or overloading.
Dual Spacing
The measurement in inches from the center of one dual tire's tread to the other. Proper spacing allows air circulation.
Durometer
A device that measures the hardness of rubber. The durometer reading indicates the tire tread's hardness level.
Dynamic Balance
Balancing the tire and wheel assembly while it's spinning.
Feather Edge
Sharp feathered wear pattern along a tread rib or block caused by scrubbing from a misaligned wheel.
Flange
The vertical rim collar that helps hold the tire beads in place.
Flap
A rubber strip used in tube-type tires to protect the inner tube from getting pinched or damaged.
Flat Spot
An isolated worn spot on the tread, which can result from excessive brake lockup.
Flat Tread Profile
A tread design with a very slight curve from shoulder to shoulder for an overall flatter shape.
Flexing
The repeated bending and flexing of the tire as it rotates.
Flexing Line
The circumferential line around the tire where the maximum bending and flexing occurs.
Flotation
The tire's ability to support the vehicle's weight on soft, yielding surfaces like sand or mud.
Footprint
The portion of the tread that actually makes contact with the road surface.
Free Radius
The radius of the tire and wheel assembly when it's not loaded or deflected.
Friction
The gripping force between the tires and the road that provides traction.
Front Wheel Shimmy
An abnormal side-to-side vibration or wobbling of the front wheels.
Front Wheel Tramp
An abnormal up-and-down vibration or hopping of the front wheels, often at higher speeds.
Gouging
When rocks, stubble, or debris in the road chisel into the tire's tread.
Groove
The channels or spaces between the raised tread ribs or blocks.
Handling
How well the tire grips and performs during driving, particularly in turns and corners.
Harshness
How well (or poorly) the tire is able to absorb and isolate small road imperfections and vibrations.
Heat Build-Up
An increase in the operating temperature of the tire beyond what can be dissipated.
Heat Dissipation
How effectively heat is removed or radiated away from the tire's surface.
Heel and Toe Wear
Sloping or angled wear at the ends of some tread elements, indicating shifting movement while rolling.
Highway Tires
Also known as summer tires, designed primarily for wet and dry pavement use but not suitable for snow/ice.
Hydroplaning
When the tires lose direct contact with the road surface due to standing water, causing them to skim or plane along the top.
Impact Break
A rupture or separation in the tire's c
Impact Resistance
The tire's ability to withstand sudden shocks or impacts without sustaining internal damage.
Innerliner
The innermost layer of a tubeless tire that helps prevent air from permeating through.
Kilopascal (kPa)
The metric unit used to measure air pressure. There are 6.9 kPa in 1 psi.
Liner
See Innerliner.
Load Carrying Capacity
The maximum load a tire can support under specified conditions, according to the manufacturer's ratings.
Loaded Radius
The distance from the wheel's axis to the ground when the tire is under its rated load and inflated properly.
Loaded Section Height
For a loaded tire, the measurement from the wheel rim to the outer tread surface.
Load Index
A number ranging from 0 to 279 that corresponds to the maximum load a tire can carry at speed.
Load Range
A designation (like B, C, D) that identifies the tire's ply rating and load range or carrying capacity.
Low Profile Tire
A tire with a shorter sidewall height, less than 80-85% of its width, giving it a squatter appearance.
Maximum Inflation Pressure
The maximum air pressure to which a cold tire can be inflated, per the manufacturer.
Maximum Overall Width
The maximum outside measurement across the tire from sidewall to sidewall when inflated but not loaded.
Maximum Rated Load
The highest load rating for which a tire or vehicle is designed and built to carry.
Misalignment
When the steering and suspension components are out of adjustment, causing improper wheel angles and operation.
Mold
The heated metal cavity or form that gives the tire its shape during the curing/vulcanization process.
Mono-Ply Tire
A tire constructed with just a single body ply or casing layer.
MSRP
The Manufacturer's Suggested Retail Price, though actual prices can vary by retailer or region.
Mud Traction
How well a tire can grip and perform in muddy conditions.
Nominal Rim Diameter
The approximate, numerical diameter of the wheel rim where the tire beads seat, like 15" or 16".
Non-Directional Tread
A tread pattern designed to perform equally well in either rotational direction.
Off-Road Traction
The tire's capability on unpaved surfaces like dirt, mud, grass, etc. for starting, stopping and overall grip.
Original Equipment (OE)
Referring to the tire size and models supplied by automakers on new vehicles from the factory.
Overall Diameter
The total diameter of the inflated tire when it's not carrying a load.
Overall Width
The overall measurement from outside sidewall to sidewall across the whole tire assembly.
Over-Inflation
Having too much air pressure in the tire, beyond the recommended level.
Over Deflection
Excessive distortion or bending of the tire due to underinflation, overloading, or both.
Overload
Operating a tire with more weight/load than its rated capacity at its current inflation pressure.
Oversizing
Using larger tires than the vehicle's specified size to increase load capacity or flotation ability.
Oversteer
A handling condition where the rear tires lose traction before the front, causing a tendency to spin out.
Ozone and Ozone Checking
Ozone is an atmospheric gas that accelerates rubber aging and cracking. Ozone checking refers to the cracks it causes.
Performance Handling
How well a tire responds, grips, and balances grip during spirited driving conditions and aggressive maneuvers.
Pinned
Having small holes drilled into the tread to accommodate metal or plastic studs for added traction.
Plug Repair
A tire repair using a plug or stemmed filler material inserted through a puncture hole while inflated. Not considered a permanent fix.
Plus-Sizing
Upgrading beyond the original equipment tire size by using a wider, lower profile tire on a larger diameter wheel.
Plus 0, 1, 2
Different levels of plus-sizing, from just a wider/lower tire to a whole wheel/tire package upgrade 1 or 2 sizes up.
Ply
A rubber-coated layer of parallel fabric cords that extends from bead to bead forming the tire carcass body.
Ply Rating
An indicator of the tire's strength or load rating, not its actual ply count.
P-Metric
The standard sizing system that uses metric measurements to indicate a tire's width, aspect ratio, construction type, rim diameter, load index, and speed rating. Like P225/60R16 91H.
Pneumatic Tire
A tire that is inflated with air pressure. Essentially any typical tire used on vehicles.
Pressure Build Up
An increase in the tire's air pressure caused by heat buildup from driving/operating conditions.
Private Brand
A line of tires manufactured for and sold under a company's own branding specifications, rather than a major tire maker's brand.
Profile
The cross-sectional shoulder-to-shoulder arc or curve of the tread area's shape.
PSI (Pounds per Square Inch)
The unit used to measure a tire's air pressure, indicating how many pounds of air are pressing on each square inch inside the tire.
Puncture
Any penetration through the tire, like from a nail or glass, that allows air to escape rapidly and causes a flat.
Quiet Ride
How smoothly and quietly the tire operates on the road with minimal noise or vibration transmitted to occupants.
Radial Cracking
Cracks that form circumferentially around the tire, perpendicular to the tread grooves, often in the shoulder or sidewall area.
Radial Ply Tire
A tire where the body ply cords run at a 90-degree angle to the direction of travel, rather than on a bias like older tires.
Radial Runout
A measurement of how "out-of-round" the tire is when spinning under load. More runout causes vibration and roughness.
Rapid Air Loss
The sudden, instantaneous rupturing or failure of the tire body that causes a complete and rapid loss of air pressure.
Rated Load
The maximum load a particular tire size and type is rated or approved to carry at the proper inflation pressure.
Replacement Tire
Any tire other than the original equipment tires supplied from the factory on a new vehicle.
Retail Price Tiers
- Premium: The highest price tier for a product category
- Moderate: The mid-range price tier
- Economy: The lowest cost, budget price tier
Reversion
Excessive heat exposure that causes a cured tire's rubber compound to deteriorate and lose its intended properties.
Revolutions per Mile (RPM)
The measured number of revolutions a tire makes for each mile of travel, which varies with tire size, load and inflation.
Rib
One of the raised circumferential sections or blocks that make up the tire's tread pattern.
Rim
The metal wheel component that the tire beads mount and seal against to contain the air pressure.
Rim Bruise
Damage to the tire's inner surfaces from forceful impact against an obstacle like a curb or pothole.
Rim Diameter
The diameter measurement of the wheel rim where the tire beads seat, like 15" or 17". Also called bead seat diameter.
Rim Protector
A raised rib or ridge on the upper sidewall that helps protect against curb scuffing or abrasions.
Rim Seat/Flange
The curved edges or flanges of the rim that the tire beads snap into and seal against.
Rim Width
The measurement across the rim between its inner flanges, where the tire's beads seat. Wider is stiffer but improves handling.
Road Hazard
Any sort of obstacle, debris or imperfection on the road that can potentially damage a tire.
Road Shock
The impacts and vibrations transmitted from road imperfections up through the tires into the vehicle.
Rock/Stone Drilling
When a rock or debris penetrates and gets trapped in the tire's tread grooves, drilling holes as it spins.
Rolling Circumference
The linear distance a tire travels in one complete revolution, which varies with inflation pressure and load.
Rolling Radius
The distance from the wheel's axle or rotation point out to where the tire makes contact with the ground.
Rolling Resistance
The energy or force required to keep a tire's rolling motion going. Lower resistance improves efficiency.
Rotation
The practice of periodically moving the vehicle's tires to different positions in a set rotation pattern to promote even wear.
Run Flat
The type of damage or distortion a tire suffers from being operated with very low or no air pressure.
Safety Tips/Tire Mixing
For best performance, it's recommended to use the same tire size, type and model on all four wheel positions. Different tires may have different casing materials or construction.
Always check your vehicle's owner's manual for specific recommendations, especially on 4WD vehicles which may require special precautions for mixing tires.
Tires marked M/S, M+S or M&S meet the industry's definition for snow/mud tires. Tires without this marking are not recommended for winter/snow use.
Seat Rim
The portion of the wheel rim where the tire's beads rest and seal against.
Section Height
The height of the tire's sidewall, measured from the rim up to the outer tread surface.
Section Width
The linear measurement across the tire from sidewall to sidewall when properly inflated but not carrying a load.
Self-Supporting System (SSS)
A special tire construction that allows temporary operation even in the event of a complete loss of air pressure.
Self-Cleaning
Referring to a tread design that uses the tire's flexing to expel mud and debris from the grooves.
Series
Tires with the same aspect ratio or relationship between section height and width.
Shimmy
A wobbling or oscillating vibration from side-to-side, often in the vehicle's front wheels. Can be caused by many factors.
Shock Absorber
The cylindrical hydraulic damping device that keeps the vehicle's springs from continually bouncing after an impact.
Shoulder
The outer edges of the tread area where it meets and blends into the sidewalls.
Sidewall
The upper area of the tire between the tread and bead areas.
Sipes
Thin slits or cuts across the tread blocks that provide more biting edges and help evacuate water for increased traction.
Size
The combination of a tire's width, aspect ratio, construction type, and rim diameter used to differentiate and indicate sizing.
Skid
A loss of traction where the tires just slide across the surface rather than rolling normally.
Slip Angle
The angle difference between the direction the tire is pointing and the direction it's actually traveling due to forces and distortion.
Speed Rating
An alphabetical code that indicates the maximum speed capability for a given tire when properly loaded and inflated.
Spreader
A tool used to forcibly spread the tire's beads apart to allow access to the interior for inspection or repairs.
Squirm
The distortion and movement of the tread area as it cycles through the different loadings and forces during rotation.
Stability
How well the tires maintain the intended direction and path, resisting body sway or deviation through curves.
Static Balance
The balance or distribution of weight when the wheel and tire assembly is stationary and not spinning.
Static Loaded Radius
The radius of the loaded tire measured from the axle center down to the ground when stopped.
Static Wheel Balancer
A type of balancing machine that checks for imbalances while the wheel/tire is not rotating.
Steel Belted Radial
A radial tire that uses steel cord reinforcement for its belt layers under the tread area.
Street Handling
How well a tire performs for everyday driving situations like turns, maintaining stability, providing steering feel, etc.
Stud
A metal or rigid plastic pin that gets inserted into a "pinned" tire to increase traction on ice and snow.
Traction
The gripping ability and friction between the tires and road surface. Traction ratings range from AA (best) to C.
Tramping
A type of abnormal up-and-down bouncing or hopping motion, often in the vehicle's front suspension.
Tread
The outermost rubber portion of the tire that makes contact with the road. Its pattern is the tread design.
Tread Depth
The measurement in 32nds of an inch from the tread surface down to the bottom of its grooves.
Tread Design
The specific pattern, grooves and block elements that make up the tread portion.
Tread Elements
The raised rubber blocks, ribs or lugs that make up the tread pattern, separated by grooves and sipes.
Tread Life
How long the tread portion of a tire will last before it needs to be replaced due to wear, measured in miles.
Tread Rib
One of the circumferential rows or ribs of tread rubber around the tire.
Tread Wear
An indication or rating of how long a tire's tread should last and resist wearing down under normal driving conditions.
Tread Separation
When the tread rubber begins peeling or pulling away from the tire's inner body/casing.
Tread Wear Indicator
Raised wear bars or indicators molded into the tread grooves that become flush with the surface at 2/32" depth.
Tread Width
The portion of the tread pattern's width that actually makes contact with the road during driving.
Tube
An air-tight rubber liner that gets inflated and holds the air pressure inside a tube-type tire.
Tuner
Referring to tire/wheel dimensions and sizing focused more on enhanced aesthetics rather than pure performance.
Under-Inflation
When a tire is inflated to an air pressure level below the minimum recommendation for the load.
Understeer
A handling condition where the front tires lose traction before the rears through a turn, causing a tendency to go straight.
Undertread
The base rubber layer underneath the raised tread elements and grooves, just above the casing plies.
Uniform Tire Quality Grading (UTQG)
A standardized grading system that allows comparison of tires' relative performance in the areas of treadwear, traction, and temperature resistance.
Valve Assembly
The combined valve stem, core and cap that allows a tire to be inflated and deflated.
Valve Cap
The small threaded cap that covers the valve stem and forms an air-tight seal.
Valve Core
The internal check valve mechanism that seals air inside the tire when inflated.
Valve Extension
An extension piece added to make the valve stem longer and easier to access, often used on inner dual tires.
Valve Stem
The rubber coated stem portion that protrudes from the wheel to allow air passage.
Vehicle Placard
A label showing the recommended tire sizes and cold inflation pressures for that specific vehicle model.
Wear Bars
See Tread Wear Indicator.
Weather Checking
Surface cracking in the rubber caused by atmospheric conditions like ozone, UV, etc.
Weight
The relative emphasis or importance given to each performance category in an overall rating score.
Wet Traction
How well a tire is able to resist hydroplaning and maintain grip on wet road surfaces.
Wheel Alignment
The configuration and angling of the wheels relative to each other and the vehicle to promote straight tracking.
Wheel Balance
Using small adhesive weights to counterbalance any imbalances or heavy spots in the wheel/tire assembly.
Wheelbase
The distance between the centerline of a vehicle's front and rear axles.
Winter Tire
A tire designed specifically for optimal traction on ice and packed snow using special tread compounds and patterns.