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Glossary of Tire- and Sealant-Related Terms
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Air Migration

The characteristic of pressurized air within a tire to seek (migrate) a path through minute imperfections contained within the rubber and component layers to an area of lower pressure (outside). This tendency is amplified by heat generated from weight and rolling resistance and often results in tire de-lamination, premature aging and shortened tire life.

Alignment of Vehicle

A wheel alignment adjustment may be necessary if the vehicle pulls to the right or the left when the steering wheel is in straight ahead position. This is another indicator of the need for an alignment check is if tires are wearing unevenly.


Specialized chemicals designed to retard oxidation commonly associated with rusting or corrosion of metals exposed to air.


Specialized chemicals designed to retard ozone contamination of rubber preventing premature aging, brittleness and retention of suppleness and pliability.


At high speeds, tires generate enormous centrifugal forces. Even tiny irregularities in the tire of only a few grams are multiplied by many orders of size. Imbalance stresses tires and suspension. Every time a tire is fitted to a wheel, it should be balanced.


The portion of a tire that seats against the rim flange. Encompassing high tensile steel wires wrapped and reinforced by plies.

Bead Leaks

Air leakage from inside a tire that escapes between the tire bead and the rim.


Slow emission of air and/or Ultraseal from a wound.


An assembly of plies extending from shoulder-to-shoulder of a tire and providing a reinforcing foundation for the tread. In radial-ply tires, the belts are typically reinforced with fine steel wire having high tensile strength.

Carcass or Casing

The main body of a tire, includes the sidewall, belts (steel, if applicable) and surface beneath the tread that bears the load when the tire is inflated.


Minute cracking in the rubber caused by aging and oxidation. (See "Weather Checking").


Describes the unique ability of Ultraseal to stay coated throughout the inner surface of the tire and wheel.


When Ultraseal is forced into a wound, the fibers entwine and prevent air from escaping as the rubber recovers from the removal of a puncturing object.


When the proper amount of Ultraseal is installed into a tire, there will be a sufficient amount of product to cover the inner surface of the tire and wheel.


The strands forming the tire plies.

Cost Per Mile

Total cost, including any repairs and recaps, divided by total mileage. In some cases, downtime may also be taken into consideration.


The tread region between the shoulders of a tire.

Curing Process

Ultraseal's unique ability to set up and form (when exposed to ambient air) a positive and secure clot in a wound.

Date of Manufacture

The date of manufacture of a tire is indicated on the tire's sidewall at the end of the DOT serial number. Tire manufacturers have adopted a standard identification system: four numbers, which indicate the week and the year of manufacture. For example, the figures 0201 indicate that the tire was made in the second week of the year 2001. See chart in Knowledgebase | Tire Terminology for additional information regarding specific tire markings and label.

Dry Rot

As a tire ages, the tire's composition is attacked by road contaminants, oxidation and ozone which reduce the flexibility and rubber recovery of all tires. This aging process is inevitable, but with the addition of anti-oxidants and anti-ozidants by tire manufacturers and Ultraseal, the tire and casing are able to last much longer.

Dynamic Balance (aka Spin Balance)

A method of balancing a wheel and tire assembly while it is spinning (usually above 300 rpm) to determine placement of corrective weights to insure smooth, balanced operation.


The distortion and twisting of a tire as it rolls along the road with the vehicle's weight and the uneven surface of the pavement. Turning also causes flexing. Flexing may be induced by hitting a tire with a mallet or by bouncing the tire.


Circumferential channels between tread ribs.

High-performance Tire

A passenger tire designed for the highest speed and handling, generally having the speed symbol W, Y, or Z in the United States molded on the tire sidewall and inflated to higher pressures than are normal passenger tires.

Inner Air Cavity

The total area of the inside of the tire and wheel forming an air chamber.

Inner Liner

Layers of low permeability rubber that are laminated to the inside of a tubeless tire to ensure the air retention quality of the tire body.

Life of the Tire

Refers to tread depth. The actual amount of tread remaining on a tire before it is required by the Federal law to be removed from service, typically 2/32î. A tire worn beyond this measurement is past its legal life.

Light Truck Tire (LT)

A tire used on light-duty trucks. These tires contain the prefix “LT” before the metric size designation. LT tires are not regulated as passenger tires.


To cover or hide significant damage to a tire.


When a tire is stretched or deformed, it will recover to its molded shaped. When a tire sustains a puncture, the puncturing object punches a small hole and stretches the rubber in order to cause penetration. When the puncturing object is removed, the rubber returns to its original state. (See Rubber Recovery).

Mixing Tires

It is recommended that all four tires on a passenger vehicle be of the same size, construction and speed rating.


National Highway Traffic Safety Administration. Among its responsibilities, NHTSA administers the Federal Motor Vehicle Safety Standards, the Uniform Tire Quality Grading system, and the corporate average fuel economy program.

OEM (Original Equipment Manufacturer)

A manufacturer of original equipment on motor vehicles.

OE Passenger Tire (Original Equipment Passenger Tire)

A tire that is provided as original equipment on new passenger vehicles. Such tires are often designed for particular vehicles to the specifications of the automobile manufacturer.

Passenger Tire

A tire constructed and approved for use on passenger vehicles and that usually contains the prefix “P” before the metric size designation on the tire sidewall. Federal Motor Vehicle Safety Standards and Uniform Tire Quality Grading standards are established specifically for passenger tires.

Performance Tire

A passenger tire intended to provide superior handling and higher speed capabilities and generally having a speed symbol of “H” or “V” in the United States.


Layers of fabric that make up the cord body of a tire. A sheet of rubber-coated parallel tire cords.

Ply Separation

A breakdown of the bonding compounds resulting in the plies detaching from each other. Usually as a result of excessive heat.

Pneumatic Tire

An air-filled tube or tubeless tire.


Rubber is not solid. It contains many pores. These pores are known to link together to create a passageway (porosity) for air to escape from within the tire.

Porosity Leaks

Refers to the air that is slowly escaping from a tire. (See Porosity).

Positive and Secure Repair

An Ultraseal-formed repair that is airtight and will not dislodge or dissolve from exposure to water, external contaminants and tire flexing.

Premature Tire Failure

Any tire that does not achieve the maximum mileage as rated by the tire manufacturer.

Radial Ply

Tire casing plies that cross the crown at a 90º angle where two or more plies of reinforced belts encircle the tire under the tread.

Radial-ply Construction

A pneumatic tire construction under which the ply cords that extend to the beads are laid at approximately 90º to the centerline of the tread. Two or more plies of reinforced belts are applied, encircling the tire under the tread. Radial-ply tires were introduced in Europe during the 1950s and came into common use in the United States during the 1970s.


A tire requires a specific amount of Ultraseal depending on its size. The required amount has been carefully calculated to provide the proper coating, plus an additional amount to provide for future punctures and a margin of safety.

Retread Tire

A used casing that has a new tread rubber applied to it.

Return Spout

A special collar attached to the Ultraseal pail or drum designed to hold the installation pump in place. It contains a valve resembling a tire valve referred to as the "return spout". It provides a location to secure the hose and vent back-pressure built up from the sealant installation process. Additionally, it blocks air from entering the Ultraseal container, hose or accessories between installations. (See Shut-Off Valve).

Rim Diameter

The diameter of a wheel measured at the intersection of the bead seat and the flange. The rim diameter is listed in the size designation on the passenger tire sidewall. Common rim diameters for passenger tires range from 13 to 20 inches.

RMA (Rubber Manufacturers Association)

RMA is the national trade association for the rubber products industry in the United States. Most domestic and foreign tire makers who produce tires in the United States are members of the association.

Rolling Resistance

Rolling resistance is caused by the deformation of a rubber tire at the point where it meets the surface on which it travels. Tires are not rigid, but flexible. During driving the tires compress, and flex. This flexing absorbs energy, converting it into heat. The lower the air pressure and/or the higher the force exerted on the tire, the larger the coefficient (resistance).

Rolling resistance is also the function of the type of rubber used. In order to reduce rolling resistance, manufacturers use special rubber compounds. Also, tires are not made entirely of rubber, but contain structures that make them more robust, i.e. bias-play tires vs. steel-belted radials.

Any reduction in the rolling resistance of the tire helps reduce fuel consumption. To reduce rolling resistance, it is recommended to check tires’ air pressure regularly.

Run-flat Tire

A type of pneumatic tire constructed of special materials, supports, and configurations that allow it to travel for a limited distance and speed after experiencing a loss of most or all inflation pressure. While these tires usually have greater weight and resultant rolling resistance, they permit the elimination of storage space and weight associated with a spare tire and jack.

Rubber Recovery

When a tire is stretched or deformed, it will recover to its molded shaped. When a tire sustains a puncture, the puncturing object punches a small hole and stretches the rubber in order to cause penetration. When the puncturing object is removed, the rubber returns to its original state. (See Memory).

SAE (Society of Automotive Engineers)

SAE technical committees have developed standardized test practices for measuring the rolling resistance of tires.

Sealed Air Chamber

A tire and wheel assembly that has been treated with Ultraseal creating an airtight chamber capable of retaining air pressure indefinitely.

Section Height

The linear distance between an inflated, unloaded tire’s overall (outside) tread diameter and the intersection of the bead seat and flange.

Section Width

The linear distance between the outside sidewalls of an inflated, unloaded tire (not including decorations such as lettering) when mounted on the measuring rim. Treads are always narrower than the section width.

Self-Sealing Tire

Any pneumatic tire treated with Ultraseal becomes a self-sealing tire capable of maintaining proper air pressure and sealing punctures as they occur.


Outer edges of the tread area connecting the sidewalls.

Shut-Off Valve

A component of the tools needed to install Ultraseal. This unit is connected to the outer end of the pump hose between the hose end and the Quick Disconnect. Its sole purpose is to trap the pressure that is accumulated in the hose and the pump after servicing a tire filled with air. By trapping the pressure, the Shut-Off Valve will prevent Ultraseal from squirting onto the tire and wheel when the VCR is removed from the valve stem and placed on the Return Spout. (See Return Spout).


The portion of the tire between the tread shoulder and bead.

Speed Rating

A letter assigned to a tire denoting the maximum speed for which the use of the tire is rated (e.g., S=112 mph, H=130 mph). The speed rating is contained in the tire size designation molded on the sidewall.

Temporary Spare Tires

Temporary spares are designed to carry the same load as the standard size tire on your vehicle and can be applied to any position. Maintain the proper inflation pressure as shown on the sidewall of the tire, it requires a higher inflation pressure than a standard size tire. Refer to the information on the sidewall of the tire for proper usage & speed restrictions. With such a tire, a vehicle may be operated until it is convenient to repair or replace the disabled tire. Have your standard tire repaired or replaced as soon as possible, then return the temporary spare to the trunk to conserve its useable tread life. The temporary tire can be worn down to the tread wear indicators, same as your standard tire. At such time the tire must be replaced.


Thixogel™ is a proprietary combination of environmentally friendly chemical components that form the foundation of the liquid fiber matrix that together with over 25 chemical and fiber ingredients is Ultraseal. Thixogel™ creates a bond that holds the liquid and fiber ingredients in suspension remaining consistent even when subjected to heat, sheer and centrifugal force. This allows the proper balance of liquid and fiber to be present should a puncture occur.


The visco-elastic property of Ultraseal's proprietary formula that provides a uniform and even coating that remains consistent when subjected to sheer and heat created within a rotating wheel and tire.

Tire Life Extender

Ultraseal is a tire sealant and tire life extender, hence the name Ultraseal Tirelife Extender/as, a term we coined and registered in the 1970s. This is the defining difference between Ultraseal and all competitors' products that are primarily limited to puncture sealing. Ultraseal has the unique ability to evenly coat a tire's interior with a chemically consistent liquid fiber matrix that effectively forms an airtight chamber that greatly improves air pressure retention.

Ultraseal's proprietary Thixogel™ resists the effect of centrifugal force that typically pulls liquid coatings away, preventing uniform and consistent coating. In addition, Thixogel™ forms a chemical bond that is unbroken by heat and sheer preventing Ultraseal from degrading or separating. All of these factors contribute to cooler running tires, enhanced tread and casing life, reduced ply separation, and the ability to seal punctures up to ¼" (½" for XHD formula) in the tread area as they occur. Test data and field reports confirm that Ultraseal-treated tires last up to 25% longer.

Tire-Related Downtime

Vehicle operating time loss due to tire-related failure.

Tire Sealing Process

Ultraseal's trade name, established to differentiate the capabilities of Ultraseal over conventional tire sealants.

Tire Valve

The valve, fitted in the wheel, ensures that the tire can be filled with air. The correct valve is required for the correct wheel/tire assembly, this is the job of the tire dealer. The cause of a slow loss of air pressure can be a defective valve. The valve cap should always be fitted to the valve in order to protect the valve core from dirt and moisture.

Tire Valve Cap

The valve cap, although small, has a very important job: it protects the sensitive valve internals from dust, dirt and humidity. If valve caps are lost they should be replaced immediately in order to avoid expensive damage later.

TPMS (Tire Pressure Monitoring System)

A warning system in motor vehicles that indicates to the operator when a tire is significantly under-inflated. Some systems use sensors in the tire to transmit pressure information to a receiver. Some do not have pressure sensors, but rely on wheel speed sensors to detect and compare differences in wheel rotational speeds, which can be correlated to differences in tire pressure.


The peripheral portion of the tire designed to contact the road surface. The tread band consists of a pattern of protruding ribs and grooved channels on top of a base. Tread depth is measured on the basis of groove depth. Traction is provided by the tread.

Tread Area

The surface of a tire that is in contact with the road. (See Crown and Tread).

Tread Compound

The general term that refers to the chemical formula of the tread material. The compound consists of polymers, reinforcing fillers, and other additives that aid in processing and slow degradations from heat, oxygen, moisture, and ozone.

Tread Depth

The distance from the top of the tread to the base (depth) of the tread grooves, measured in 32nds of an inch from the centerline of the tread.

Tread Design

The pattern of the tread.

Tread Separation

Pulling away of the tread from the tire casing, normally caused by heat as a result of porosity (air migration).

Tread Wear

The tread wear grade is a comparative rating based on the wear rate of the tire when tested under controlled conditions on a specified government test track. A tire graded 200 would wear twice as long on the government test course under specified test conditions as one graded 100. It is wrong to link tread wear grades with your projected tire mileage. The relative performance of tires depends upon the actual conditions of their use and may vary due to driving habits, service practices, differences in road characteristics and climate.

Tread Wear Life

Total miles traveled by a tire until its tread wears out, which is usually defined as a remaining groove depth of 2/32 inch for a passenger car tire that exhibits even wear.

TWI (tread wear indicator)

Tread wear indicators ("wear bars") are located at the base of the main grooves and are equally spaced around the tire. Always remove tires from service when they reach a remaining tread depth of two thirty-seconds of an inch (2/32"). If not corrected, wet weather accidents are more likely to happen due to skidding on bald or nearly bald tires. Also, excessively worn tires are more susceptible to damage from road hazards. Built-in treadwear indicators, or "wear bars," which look like narrow strips of smooth rubber across the tread, will appear on the tire when that point of wear is reached. When you see these wear bars, the tire is worn out and it's time to replace the tire.

USDOT (U.S. Department of Transportation)

The National Highway Traffic Safety Administration is an agency of USDOT.

VCR (Deluxe Valve Core Remover)

A specially designed patented tool used to install Ultraseal into a fully inflated tire. The Deluxe VCR tool is quickly attached to the chuck at the end of the pump hose. It allows easy removal and re-installation of the valve core while holding a tire's pressure as Ultraseal is installed.


A viscoelastic material is characterized by possessing both viscous and elastic behavior. A purely elastic material is one in which all energy stored in the material during loading is returned when the load is removed. In contrast, a purely viscous material stores no strain energy, and all of the energy required to deform the material is simultaneously converted into heat. Some of the energy stored in a viscoelastic system is recovered on removal of the load, and the remainder is dissipated as heat. Rubber is a viscoelastic material.

Weather Checking

A condition that appears as cracks in the sidewall typically caused by UV exposure and environmental contaminants.