People keep asking me about some abbreviations on tires from different brands. So, I’ve created this page for quick reference. You can quickly check Manufacturer Abbreviations, Runflat shortcuts, Tire Abbreviations, All tire markings, and technical terms (from A to Z).
Hope you find this page useful; please share if your friend or family member needs it.
Table of Contents
What are Tire Markings?
Tire marking refers to the information that is printed on the sidewall of a tire. This information includes details such as the tire’s size, type, load capacity, speed rating, and other relevant information. Tire marking is important because it helps ensure that the tire is suitable for the vehicle and the conditions in which it will be used.
It also helps with maintenance and repair, as it provides key information that can be used to identify the appropriate replacement tire or to diagnose issues with the existing tire.
|AM8, AM9, AMS, AMR, AMV, AMP, AMX
|Aston Martin (Aston Martin Rapide, Aston Martin Vantage)
|Audi Original Extended (Runflat)
|RO1, RO2, RO
|Audi Quattro (4WD models)
|B, B1, BC, BL
|depending on the manufacturer Ford or Ferrari
|Ferrari; but can also be a special identifier on Pirelli tires, then has nothing to do with Ferrari!
|LR, LRO, LRO1, LRD
|Land Rover, Land Rover Discovery
|Lotus Exige S
|Mercedes Original Extended (Runflat)
|N0, N1, N2, N3, N4, N5
|Various identifiers recommended by Porsche
|BMW run-flat system component
|BMW run-flat system component
|Audi Original Extended
|Dunlop Self Supporting Technology
|Extended Mobility Technology (Goodyear)
|Flat Run Tyre (Nokian)
|Hankoook Runflat System
|Mercedes Original Extended
|Run On Flat (Goodyear & Dunlop)
|Self Supporting Tire (Michelin)
|Extended Runflat Technology (Kumho)
|Zero Pressure (Michelin)
From A to Z: Index of keywords
ABE: Abbreviation for ” General Operating Permit”.
Abrasion: When a car is driven, braked and started, both the surface of the tires and the road surface are abraded.
Rolling circumference: The distance covered by any point on the tread in one wheel revolution. Thus, the rolling circumference depends on the tire diameter, it affects the gear ratio as well as the speedometer drive. Based on the standard tire, a tire with a smaller rolling circumference tends to have a shorter gear ratio. Acceleration is favorably influenced, but at top speed the tachometer could be in the red zone. In addition, the smaller tire brings a larger speedometer lead. Tolerances of plus 1.5% and minus 2.5% are acceptable. Larger deviations require at least a correction of the speedometer reading.
Aging: Various factors can influence the tire aging process: Humidity, UV radiation, heat and cold, etc. To prevent a drop in performance, substances are added to the rubber compound that greatly slow down the aging process. However, after ten years you should replace your old tires with new ones.
Requirement profiles: See also Load Capacity. Every tire must ensure the load-bearing capacity of the vehicle’s weight as well as transmit the highest possible drive forces, braking forces and lateral forces – on dry roads, in damp, wet conditions, on snow and ice. Other requirements: High-speed resistance, robustness, abrasion resistance, low rolling resistance, low noise, suspension characteristics, good-natured handling, aging resistance.
Stopping distance: braking distance plus reaction distance gives the actual stopping distance. Stopping distance on dry roads with a reaction time of 0.3 s and with a reaction time of 1.7 s
50 km/h = 17.93 m = 37.38 m
70 km/h = 30.02 m = 57.24 m
100 km/h = 53.41 m = 92.30 m
130 km/h = 83.11 m = 133.66 m
Aquaplaning: The floating effect when the amount of water standing on the road can no longer be channeled by the tire’s drainage grooves.
Contact patch: The area with which the tire contacts the ground.
Balancing: Attaching weights to the rim to keep the wheel running true. Poorly balanced wheels place excessive stress on the tire, wheel bearings and suspension.
Bar: Bar is a unit of measurement for air pressure.
Bionics: Learning from nature and transferring what is learned to technology.
BioTRED: Name for the first filler made from a renewable raw material: corn. It enables tires to be manufactured in a more environmentally friendly way and has a low rolling resistance, which helps save gasoline and thus money through lower fuel consumption. It also improves tire characteristics that are important for safety, such as wet braking. BioTRED is so far only used in the Goodyear GT 3.
Curb parking: See also carcass. Driving over curbs briskly can cause crushing of the carcass threads, leading to tire failure.
Wide tires: See also aquaplaning. There is no standard definition of wide tires; most commonly, it refers to tires with a sidewall height of 55 mm and smaller (e.g., 205/55 R 16). Advantages: Significant increase in driving stability, much better steering precision, installation of larger and more effective braking systems is possible, better high-speed capability.
Braking distance: The distance covered while pressing the brake pedal. The following have an influence on the length of the braking distance: reaction time, brake response time, brake swell time, road conditions (type, wetness), tire condition (make, tread depth, inflation pressure), speed.
Cords: See also bead, bias tire, belted tire, radial tire. Threads made of rayon, nylon or polyester as the decisive strength member. The fabric is embedded in the rubber. The course of the threads from bead to bead determines the type of tire. There are bias and radial tires.
C tires: C stands for commercial and refers to tires with a higher load-bearing capacity and a reinforced base.
Bias tire: Refers to a tire in which the cords are arranged at an angle to the direction of travel.
DOT number: The American “Department of Transportation”, which gives the tire its name, requires a number of details about the construction of the tire, which can be found in the form of numerical codes on the sidewall. In most cases, however, this refers to the date of manufacture of the tire. The age of the tire is indicated in code form. For example, “327” means the 32nd week of the year 1997. Starting from the year 2000, the week of construction and the year of manufacture of a tire are shown as four digits. This means that the last four digits indicate the week of construction and year of manufacture of the tire – for example, “1602” indicates the 16th week of the year 2002.
Eagle: Successful Goodyear product family of sporty high-performance tires.
ECE marking: § 36 StVZO prescribes the following tire markings under point 4 (tire designation): Tires on vehicles with a maximum speed of more than 40 km/h must be marked with the following: tire size, tire construction type, load capacity, speed category and date of manufacture (or tire renewal date). In addition, since 01.10.1998 the E-marking is mandatory.
Offset: Offset is the distance between the center of the wheel and the inner contact surface of the rim on the wheel hub, brake drum or brake disc. A positive offset (e.g. ET +25) means that the rim builds further inwards (i.e. towards the center of the vehicle) than outwards.
EMT: See also run-flat properties. “Extended Mobility Technology” – tires with run-flat properties. EMT tires can still cover distances of up to 80 kilometers at speeds of up to 80 km/h even after a complete loss of air pressure. Enough to safely reach the nearest tire dealer.
Spare wheel: Fifth wheel that is transported in the car largely unnoticed and unused.
Make ties: On passenger cars/motorcycles, tire makes and types were listed by name in the vehicle documents. This meant that only the named tires could be used for replacements. This decision was revoked for passenger cars in February 2000.
Driving physics: Various forces act on the vehicle that must be absorbed by the tire. These include: Engine force, centrifugal force, braking force, frictional force, longitudinal forces (starting, accelerating and braking), lateral and side forces (driving in curves).
Chassis geometry: Chassis geometry includes camber, toe and caster. Retrofitting without adjusting chassis geometry often has negative effects, such as higher steering forces or loss of straight-line stability.
Rim designations: The internationally used size designations for rims – for example, 7 J x 15 – denote the wheel width from rim flange to rim flange, here seven inches, and the diameter, here 15″.
Rim rib: A strip of rubber used to protect the rim from damage, for example from curbs.
Flank: See also speed classes, carcass, sidewall. The sidewall of the tire is referred to as the sidewall. It influences driving characteristics and comfort.
Sidewall height: The sidewall height is related to the tire width. This means that for a tire size of 175/70 R 13 S, the value 70 (70% of the tire width) indicates the height of the tire. One talks of a tire of the series 70. There are at present series from 80 to 25. From a value smaller than 55 one speaks of wide tires.
Centrifugal force: Force that pushes the vehicle outward when cornering – and the greater the vehicle mass and speed, the greater the force.
Formula 1: The top class of motorsports. Goodyear is by far the most successful tire manufacturer in Formula 1, having currently won 368 Grand Prix races.
Clearance: The tires and rims must neither come too close to the body nor graze chassis components such as brakes and tie rods.
Inflation pressure for wide tires: See also Air pressure. As a general rule, a wide tire with the same air volume as the standard model also requires the same air pressure. However, for reasons of operational safety, wide tires may require different inflation pressures than standard tires. This depends on the weight load of the tire, the maximum speed of the vehicle and the load index LI. The tire manufacturer’s specifications and your vehicle’s operating instructions are always a guide to the inflation pressure values.
All-season tire: See also Vector. Independent tire construction with balanced properties for both summer and winter conditions. Combined at Goodyear in the “Vector” product family.
Off-road tires: See also Wrangler. Tires with special properties, such as notch resistance, for off-road and off-road use. Combined in Goodyear’s Wrangler product family.
Speed index: Also called speed index (SI). The speed index indicates the maximum permitted tire speed as a function of load capacity (load index). This is released by the tire manufacturer and can be found as the last character in the tire designation. The speed index allowed for a vehicle is indicated in the vehicle registration document. Optimum continuous use is only guaranteed if the correct tire pressure and maximum load capacity are maintained.
A tire with a higher speed index than specified in the vehicle registration document may also be fitted without hesitation. However, a tire with a lower speed index may not be driven, with the exception of M+S tires (condition for this is a sticker attached to the vehicle with the maximum speed of the currently attached tire).
Speed classes: Categories for the speed index (SI), the maximum speed approved for one type of tire. The individual categories:
Maximum speed for passenger car tires; SI km/h Q=160 R=170 S=180 T=190 H=210 V=240 W=270 Y=300 and ZR Over 240 km/h
Maximum speed for C tires (tires for larger vehicles) SI km/h K=110 L=120 M=130 N=140 P=150 Q=160 R=170 S=180 T=190
Rubber compounds: A tire can consist of up to 16 different rubber compounds. However, tire manufacturers always keep the exact composition to themselves. To obtain a good tire, many requirements are placed on the rubber compound: Low abrasion, crack resistance, skid resistance, low rolling resistance, dynamic resistance, airtightness, aging resistance.
Belt separation: See also tread. When a tire is underinflated, the increased flexing causes temperatures of up to 120 °C. This can lead to partial tread separation, especially in the shoulder area. Partial material overheating occurs, especially in the shoulder area, which can cause parts of the tread to detach.
Belted tire: See also carcass. The belt over the carcass consists – usually in several layers – of twisted, brass- and rubber-coated thin steel wires. On top of this is a cover made of an endless bandage, which improves high-speed suitability and concentricity. The belt offers the following advantages: decisive improvement in driving characteristics, reduced rolling resistance, lowering of temperature, low block movement in the tread, less slippage, better driving stability, reduced abrasion, good steering response and stability. Caution: Steel belts can rust. Therefore, a tire that has such a deep surface injury that moisture (including humidity) can get to the steel cord must be removed from service immediately.
Manufacture: See also rubber grades. Key aspects of tire manufacture are: The defined mixing of different rubber grades and chemical additives, the production of different cord fabrics for the carcass, the production of high-strength steel cord for the belt, the bead fastening of the raw tire construction as final assembly, vulcanization in the heating press, and the comprehensive final inspection of each individual tire.
High-performance tires: High-performance wide tires designated HP (High Performance) or UHP (Ultra High Performance). These tires often have a directional tread pattern, which may be indicated by an arrow. These tires aren’t always the best at reducing road noise.
High-speed capability: To determine high-speed capability, a tire must maintain its max. speed (speed index) for one hour on a roller dynamometer. In the subsequent test, the speed is increased by 10 km/h every ten minutes until failure.
Radial runout: Deviation from the radial runout of the tire in the horizontal or vertical direction. Harmonization is only necessary in extreme cases of radial runout – which is virtually non-existent in today’s products. This involves using a special machine to reduce or completely eliminate radial runout by milling off tread rubber.
Hump: See also air pressure. Important component of modern tires. Refers to a bulge running all the way around the rim shoulder. There are usually two humps on the rim contour (wheel inner and outer). These are intended to ensure that the tire bead does not jump into the rim bed in the event of lateral loading and insufficient air pressure.
Hydrodynamic effect: Refers to accelerated water drainage through arrow-shaped, directional tread patterns and new shapes of channels running to the side.
Innerliner: Designation for the rubber layer inside the tubeless tire that ensures an airtight seal of the interior.
Intermediates: Term from motorsport for racing tires with a tread pattern hand-cut on site, which represent the best compromise on damp or drying road surfaces.
Calender: Roller system in which the cords are thinly coated with rubber on both sides.
Carcass: This essential component of the load-bearing tire substructure gives the tire its strength and ensures cohesion. Today, it is mostly made of synthetic fibers known as rayon.
Types of rubber: There are various types of rubber. In addition to natural rubber (which is extracted from the sap of the hevea tree in plantations near the equator), there is now an increasing use of synthetic rubber.
kPa: kPa (kilopascal) is a unit of measurement for air pressure.
1 kPa = 0.01 bar
1 bar = 100 kPa
Fuel consumption: The rolling resistance of a tire has a significant influence on fuel consumption. More rolling resistance also means higher fuel consumption. The EU tire label rates rolling resistance on a scale from A (= low) to G (= high). The difference between the individual classes is around 0.1 to 0.15 liters of fuel per 100 km. Low tire pressure also increases fuel consumption. This should therefore be checked regularly.
Forces on the tire: See also Driving physics.
Coefficient of adhesion: See also Coefficient of friction. This value reflects the roughness of various material pairings, i.e. between the underside of the body (e.g. tire) and the base (e.g. road), and is designated by the Greek letter µ (My). Low values represent a smooth, slippery, low-friction material pairing. At high values, the friction forces to be overcome increase.
Lamellae: Fine incisions in the tread block that act like small microgrip edges. On winter tires, for example, they increase traction when starting and braking.
Load index LI: Also called load, load-bearing or load-capacity index. The load index is an indication of the maximum load a tire can carry. Which index is permitted for a vehicle can be found in the registration certificate. On the registration number, the load index can be found before the speed index. To determine the maximum load per tire, one must compare the index number with a table. A tire with the imprint 205/55 R16 91V has a load index of 91 and may be loaded with a maximum of 615 kg. In the case of two indexes (100/97), the first digit applies when the tire is used singly and the second when two copies of this tire are used. The load index is reliable only if the recommended tire pressure and the maximum permitted speed are observed.
Tread: See also bead. The tread is in direct contact with the road surface and, together with the other tire components, is responsible for power transmission. It must realize acceleration and braking forces in the longitudinal direction and lateral forces during steering and cornering. The quality of the tread is very much determined by the substructure (belt, carcass), the bead and side sections, but crucially by the design of the tread pattern on the tread.
Tread compound: The performance level of a tire in driving conditions depends to a large extent on this compound – in wet or hot conditions and in the transmission of lateral or longitudinal forces. Even mileage and noise behavior are determined by the tread compound.
Mileage: The service life of a tire depends on the vehicle, the driving style and many other factors. On front-wheel drive vehicles, the mileage of the rear tires can be three times that of the front tires. As a general rule, the legal residual tread depth is 1.6 millimeters.
Directional tread: See also aquaplaning. Tires with directional tread are mounted in the direction of travel indicated by an arrow. They offer the following advantages: Lower noise, better traction in wet conditions, higher aquaplaning resistance. High-performance wide and winter tires in particular are increasingly being designed as directional tires.
lbs: lbs (pounds) is an American unit of measurement (weight).
1 lb = 0.4536 kg
1 kilogram = 2.205 lb
Low-rolling resistance tire: See also rolling resistance. Tire that is significantly optimized in rolling resistance thanks to new compound technologies. This is reflected, for example, in lower fuel consumption.
Light stabilizer: An agent added to the tire to make it more resistant to ozone and UV radiation.
Air pressure: The correct air pressure is of decisive importance for the mileage and service life of tires as well as for driving safety. If the tire is underinflated, this can lead to unfavorable pressure distribution and overheating, and even to the risk of a tire blowing out. In addition, rolling resistance increases, which leads to an increase in fuel consumption. Regular surveys show that only about one in four cars is on the road with sufficient air pressure.
Miles: Miles are an American unit of measurement (distance).
1 mile = 1.609 kilometers
1 kilometer = 0.622 mile
M+S: M+S means “Mud and Snow”. These initially particularly coarse tires for winter conditions and unpaved surfaces were first presented in 1950.
Minimum tread depth: See also aquaplaning. A minimum tread depth of 1.6 mm applies throughout Europe for cars, trucks and motorcycles. This minimum must be maintained over the entire tire surface. If a tire approaches this legally prescribed minimum tread depth, the braking distance in wet conditions and the risk of aquaplaning increase. In the case of a tire with a minimum tread depth of 1.6 mm, the braking distance doubles in the event of aquaplaning compared to that of a new tire. To measure tread depth, see Tread-Wear Indicator TWI.
Caution: For safety reasons, summer tires should be replaced at the latest at 2 mm tread depth, wide tires at 3 mm and winter tires at 4 mm.
Mixed tires: See also speed classes. Anyone who combines different sizes, makes, new and used tires, or summer and winter tires is living dangerously: inconsistent tire reactions can cause uncontrollable driving behavior in extreme cases. Under normal circumstances, it is completely forbidden to fit different tire sizes. The only exception is in the event of a puncture, for example, if only a narrower spare wheel or an emergency wheel (follow the manufacturer’s instructions) is available instead of the wide tire.
Regrooving: Only provided for commercial vehicle tires. Refers to the one-time deepening of the tread grooves down to the tread base. This is taken into account in the design of the tire during manufacture.
Wet grip: A measure of a tire’s braking ability on wet roads. With a Class A tire, the braking distance can be reduced to as much as 18 meters during emergency braking compared to Class F. The tire’s wet grip is measured by the tread grooves down to the tread base. In between are classes B – E, each with a one-meter braking distance difference. The braking distances refer to a driving speed of 80 km/h. Classes D and G are not used for passenger cars.
Wet performance: When braking in wet conditions, the tire must be able to absorb a lot of heat energy through its rubber compound.
Low-profile tires: The tire cross-section describes the ratio of sidewall height to tread width. The balloon tire common in the 1920s, with a height-to-width ratio of almost 1 : 1, has long since given way to the low-profile tire (up to 0.25 : 1).
Run-flat properties: A special feature of the Goodyear EMT: The tire does not jump off the rim even when pressure is lost and still allows a residual range of up to 80 kilometers at a speed of max. 80 km/h – enough to reach the nearest workshop or tire dealer. See also Run Flat.
Run-flat tire: See also EMT.
Emergency wheel: Special wheels that can be used to cover short distances after a flat tire. There are two types of emergency wheels: the narrow types, usually smaller than the driving tires, and the folding wheels, which are inflated with a compressor. Attention: riding with the emergency wheel is only allowed up to a limited speed of mostly 80 km/h. The emergency wheel should only be used for a short time. This wheel should only be used for a short time to avoid damage to the axle differential of the drive axle. If possible, the emergency wheel should be mounted on a non-driven axle.
Zero-degree cover: Thread course of the belt exactly in the direction of travel.
Commercial vehicle tires: tires developed specifically for light trucks, trucks and buses. The priorities are economy and high mileage.
Off-road tires: See also speed classes. Special tires for off-road use. The range includes mud riders, sand specialists, all-rounders for off-road and on-road use with M+S labeling, winter tires, and also high-performance tires for on-road use with speed index W (up to 270 km/h).
Ply Rating (PR): See also load capacity. Ply Rating is an obsolete load capacity designation for tires that indicated the cotton cord plies in the tire substructure (8 PR = eight plies). Today, this indication no longer has any meaning.
Tread: The tread consisting of tread negatives (grooves) and tread positives (tread blocks) is used to drain water or slush – on dry surfaces, a treadless slick would provide optimum grip.
psi: psi (pounds per square inch) is an American unit of measurement (tire pressure).
1 psi = 0.0689 bar
1 bar = 14.504 psi
aspect ratio: see also inch. Relation between the height of the tire sidewall and the width of the tire. Example: A tire of the dimension 175/70 R 13 has a width of 175 mm, the sidewall height is 70% of the width, the last two digits indicate the inch size (international).
Radial tire: See also carcass, direction of travel, bias-ply tire. Within the carcass, the rubberized cords lie in one or more layers radially, i.e. at right angles to the direction of travel. Before this, bias-ply tires were common.
Wheel load: The weight of the vehicle that rests on the tire.
Regroovable: Regroovable means “regroovable”. Tires may only be regrooved if they bear the additional marking “Regroovable” on the sidewall.
Coefficient of friction: See also slip. Value measured in My(µ) that is not constant but varies depending on temperature, surface pressure in the contact patch, slip and numerous other factors.
Friction: A value that depends on the weight of the body (more precisely: on the normal force exerted perpendicularly on the base) on the material pairing between the base (e.g. road) and the side of the body resting there (e.g. tire). Friction determines the physics of driving: when starting, when accelerating, when braking (longitudinal forces) and in curves (lateral and side forces).
Tire age: See also ECE labeling. Tire age is determined by two factors. Ozone from the atmosphere penetrates the tire rubber in small quantities and affects the sulfur compounds between the rubber molecules. The rubber loses elasticity. Especially tires that are stored unused harden and become brittle. This results in hairline aging cracks. Sun, wind and weather, as well as contact with greases, oils and chemicals, take their toll on tires.
Tire labeling: See also ECE labeling.
Tire pressure: See also inflation pressure for wide tires.
Tire size: See also Load capacity Speed ratings. The designations affixed to the sidewalls contain information on the date of manufacture and tire type as well as size designations: 175/70 R 13 T means a tire width of 175 mm and a height-to-width ratio of 0.7 : 1. The R stands for radial construction, 13 is the rim diameter in inches and T is the speed index.
Reinforced: A tire feature that is especially suitable for vans. With a reinforced carcass, this tire has an increased load capacity.
Retread: Retread means “retreaded.” A retread tire will have an “R” or “Retread” noted on the sidewall.
Rolling noise: The volume of a tire’s rolling noise is identified by the EU tire label in three classes. Firstly, these are indicated by volume symbols, and secondly with decibel values. The lowest decibel value for narrow tires is 67dB, while wide tires reach at least 71 dB. Passenger cars reach 72 to 76 dB with the highest noise class. Just 3 dB increases the rolling noise to twice that level.
Rolling resistance: See also flexing work. Rolling resistance is caused by the deformation (flexing) of the tire. The design goal is to achieve the lowest possible rolling resistance and thus lower fuel consumption.
Retreading: See also Vulcanization. Retreading is the process of applying a new tread to an old tire. The tires are either vulcanized in heating molds (hot retreading) or heated together in autoclaves (cold retreading). Each tire dimension has its own heating time.
Run Flat: A tire with run-flat properties. In the event of a puncture, the tire ensures continued driving at low speed. These properties are achieved by a support ring on the rim or reinforced sidewalls. A tire pressure monitoring system is required for run-flat tires. See also run-flat properties.
Sawtooth: Uneven wear of the shoulder tread blocks leads to sawtooth formation and an increase in noise level.
Tube: See also carcass, vulcanizing, valve. When replacing tires, care should be taken with Tube Types (tubular tires) to ensure that a new tube is used, as old tubes are expanded and may wrinkle. The wrinkling will cause imbalance and rubbing of the tube on the inside of the tire.
Slip: Refers to the relative movement between vehicle speed and tire circumferential speed. 100% slip: A wheel spins or locks.
Snow chains: See also tire size. In extreme snow and road conditions that even winter tires can’t handle, snow chains offer a way to safely reach your destination.
Ten snow chain tips:
- For quite a few wide tire sizes, chain mounting is not possible due to space limitations.
- Before buying, make sure that the chain size can be combined with the actual tires and rim.
- Chain assembly in any case practice at home.
- Be careful when combining chains and alloy wheels. Some types of chains may damage the rim.
- Always mount chains on the drive wheels, usually on the front wheels in the case of all-wheel drive. If in doubt, consult the vehicle manufacturer.When driving with chains, the chainless wheels have considerably less lateral grip and lock earlier when braking.
- Do not exceed the maximum speed of 50 km/h with chains.
- If possible, remove the chains immediately on a snow-free road.
- After use, rinse the chains with hot water and let them dry (also stainless steel products).
- For expensive chains, it is worthwhile to have them repaired by the manufacturer. They can also be adapted to other tire sizes.
- High-speed resistance: The centrifugal acceleration acting on the tires is extreme – at 200 km/h, for example, it is a thousand times the acceleration due to gravity. For this reason, manufacturers coat the belt cord with rubber to achieve a strong bond with the rubber later on. The steel belts are also provided with several nylon covers.
Slip angle: The slip angle refers to the difference between the position of the wheel and the actual direction of travel. Thus, a large slip angle requires a large steering input to effect the change in direction. The stiffer the tire structure, the smaller this angle and the safer the ride – but at the expense of comfort.
Sulfur: Alongside many other chemicals, elemental sulfur has an important function: It is only through its addition that the long molecular chains of the rubber are crosslinked during vulcanization – plastic, sticky material becomes elastic rubber.
Snowflake symbol: See also M+S. New industry standard for easy identification of tires with tested winter properties. The official stamping – which is only carried out in combination with the M+S marking – provides a clear distinction from M+S-marked summer or all-season tires.
Sidewall: All tire information is located on the sidewall. To prevent damage, it can be provided with a rim protection strip on the outside. When driving briskly over curbs, the incorporated carcass threads can be crushed and break either immediately or later.
Self-supporting tires: See also carcass. All self-supporting products have a reinforced base, modified carcasses and belts, and stiffened sidewalls and bead zones. Since 1994, Goodyear has offered self-supporting tires under the name EMT (Extended Mobility Tire).
Severe Snow Symbol: See also Snowflake Symbol.
Silica: See also Rolling resistance, Mileage. The precipitated silica silica, in combination with a special rubber grade, enables up to 20% reduction in rolling resistance, good wet performance and high mileage.
Slick: Treadless racing tire.
SmartTRED: The SmartTRED concept ensures excellent traction in winter and optimum grip in summer. The new technology combines a wide range of tire properties. The combination of stable shoulder blocks, a heavily siped center and a special ground contact patch ensures that the tire – e.g. Vector 5 – adapts automatically and flexibly to changing road conditions.
Summer tires: See also temperatures. A tire for dry roads, high temperatures, relatively high to very high speeds with corresponding temperature loads, and damp and wet road surfaces.
Speed Index SI: See also Speed Index.
Spikes: Spikes (nails) served as a mechanical traction aid on the tire until 1975. This type of tire may nowadays only be driven with restrictions in Scandinavian countries.
Steel belt: See also rolling resistance belted tires.
Toe: Distance between the centers of the tires on an axle. May differ between front and rear axles.
Camber: See also Load capacity. Camber is the inclination of a wheel or its centerline relative to the perpendicular to the road. If the top of the wheel is inclined outward, camber is positive (+); if the top of the wheel is inclined inward, camber is negative (-). As a result, the tire contact patches are loaded on one side (inside or outside), reducing the load-carrying capacity of the tires.
Tubeless: These tires can be recognized by the tire designation tubeless.
Temperature dependence: See also slip, coefficient of friction. In addition to slip and slip angle, tire temperature has a significant effect on coefficient of friction. At colder temperatures, the coefficient of friction tends to be low, rising with increasing temperatures. If the operating temperature continues to rise, coefficients of friction and thus the transmissible forces drop again in equal measure.
Temperatures: See also coefficient of friction, air pressure. The coefficient of friction of rubber is temperature-dependent. For a summer tire to work optimally, an operating temperature of 50 to a maximum of 90 °C is ideal. If the tire overheats, for example due to insufficient air pressure, its structure will disintegrate.
Load capacity: See also load index. A multi-digit number on the tire sidewall, the so-called “load index”, provides information on the load capacity, which varies depending on the vehicle weight for the same tire size – for example for small cars, mid-size sedans or vans.
Tread-wear indicator TWI: Abrasion indicators are integrated on the tread base and form narrow, continuous ridges at 1.6 mm residual tread depth in the tread base. The position of these indicators is marked at the very top of the sidewall – depending on the tire manufacturer – by triangles, the letter combination TWI (Tread-Wear-Indicator) or small company symbols.
Oversteer: Driving behavior in which the rear tires lose grip before the front tires: The car breaks away with the rear and turns in on the curve.
Ultra-high-performance tires: See also high-performance tires.
Conversion: This refers to replacing the stock tires with wider tires and rims with an impressive look.
Understeer: Driving behavior in which the front tires lose grip before the rear tires: The car slides straight ahead in a direction tangential to the radius of the curve.
Unbalance: Even minimal variations in material density or other influences cause slight imbalances within the tire. This causes imbalance during rotation, which can be compensated for by counterweights on the rim.
Vector: Product name of the innovative Goodyear all-season tire range.
Valve: There are two types of valves: Rubber valves, which seal the rim hole itself. Screw valves, which use a sealing ring to seal. Caution: Valves are very sensitive to dirt, dust and moisture. Therefore, the valve cap should always be screwed on tightly.
Wear: Wear depends on tire aging and driving. Tire durability is determined by driving style, vehicle load, road conditions and maintenance (air pressure). Differences in performance of a few thousand kilometers are possible with the same type of vehicle and tire.
Interlocking effect: See also winter tires. To ensure that winter tires literally “bite” into the snow, they have sipe-like edges and grooves that press the snow into a “toothed track”. This creates an interlocking of tire and road surface.
Vulcanization: Last stage of tire production. In the vulcanization press, the tire blank not only takes on its final appearance, but the individual tire components also bond here through the targeted control of pressure and temperature at precise timing and become elastic rubber. This takes place at around 165 to 200 °C and a pressure of 12 to 24 bar in about 9 to 17 minutes.
Flexing work: See also rolling resistance. The periodic compression of the tire causes its deformation – known as flexing work – which releases heat and causes rolling resistance. If the air pressure is too low, the tire overheats due to an excessive amount of flexing.
Water displacement: On wet surfaces, the tire’s positive blocks must displace water through drainage grooves. For example, at 80 km/h up to 25 l of water per second are channeled (at 100 km/h up to 31 l, at 120 km/h up to 37 l, at 140 km/h up to 43 l, etc.).
Winter tires: See also sipes. In addition to a special tread pattern with sipes and a larger number of negative blocks for good grip, winter tires consist of special rubber compounds to prevent the tread from hardening in cold temperatures.
Wrangler: Goodyear family of off-road tires.
Bead: The bead – or inner ring of the tire sidewall – contains one or more wire cores and has the task of ensuring the secure fit of the tire on the rim.
Inch: Inch is an American unit of measurement (distance).
1 inch = 25.4 millimeters
Common Misconceptions About Tire Markings
There are several common misconceptions about tire markings that can lead to confusion or misunderstandings. Here are some of the most prevalent:
- The maximum inflation pressure listed on the sidewall is the recommended pressure: This is not true. The maximum inflation pressure is the highest pressure that the tire can safely handle, but it is not necessarily the ideal pressure for optimal performance and safety. The recommended pressure can usually be found in the owner’s manual or on a sticker in the vehicle.
- Tires with the same size markings are interchangeable: This is not always true. Even if two tires have the same size markings, they may have different load capacities or speed ratings, which can affect their suitability for a particular vehicle or application.
- The speed rating only applies to high-speed driving: This is not true. The speed rating indicates the maximum speed at which the tire can safely operate, regardless of the driving conditions. It is important to choose a tire with an appropriate speed rating for your vehicle and driving habits.
- Tires with higher load ratings are always better: This is not necessarily true. Tires with higher load ratings are designed to handle more weight, but they may also have a stiffer ride and lower traction. It is important to choose a tire with an appropriate load rating for your vehicle and the conditions in which you will be driving.
- The DOT number on the sidewall indicates the tire’s age: This is true to a certain extent, but it is not always accurate. The DOT number includes a four-digit code that indicates the week and year of manufacture, but some tires may have been in storage for several years before being sold, which can affect their performance and safety. It is generally recommended to replace tires that are more than six years old, regardless of their mileage or appearance.
Frequent Asked Questions
What do the marking on tires mean?
The markings on tires provide important information about the tire’s size, type, load capacity, speed rating, and other relevant details. Here are some of the most common markings and what they mean:
- Tire size: This is usually indicated by a series of numbers and letters on the sidewall, such as “225/60R16.” The first number indicates the width of the tire in millimeters, the second number is the aspect ratio (the height of the tire’s sidewall as a percentage of its width), and the last number is the diameter of the wheel in inches.
- Load index: This is a number that indicates the maximum weight that the tire can support when inflated to the proper pressure. The higher the number, the higher the load capacity.
- Speed rating: This is a letter that indicates the maximum speed that the tire can safely handle. The higher the letter, the higher the speed rating.
- UTQG rating: This stands for Uniform Tire Quality Grading and is a rating system that indicates the tire’s treadwear, traction, and temperature resistance.
What are the different types of tire marking?
There are several different types of tire marking, including:
- Sidewall markings: These are the most common type of tire marking and include details such as the tire size, load index, speed rating, and UTQG rating.
- Tread markings: These are typically found on high-performance tires and indicate the direction of rotation and other details related to the tire’s design and performance.
- Run-flat markings: These indicate that the tire is designed to continue functioning even if it has lost air pressure, and may include details such as the maximum speed and distance that the tire can travel in this condition.
What are the guidelines for tire marking?
Tire marking guidelines vary by country and region, but there are generally accepted standards that provide consistency and clarity for consumers. Some of the guidelines for tire marking include:
- Using clear, easy-to-read fonts and symbols.
- Including all relevant information, such as tire size, load capacity, speed rating, and UTQG rating.
- Ensuring that the markings are permanent and resistant to wear and weathering.
- Using consistent placement and formatting across different brands and models of tires.
- Complying with applicable safety and performance standards.
What does the 265 65R17 112t mean?
This tire size marking indicates that the tire is:
- 265 millimeters wide
- 65% of the width in height (aspect ratio)
- Designed for a 17-inch wheel diameter
- Has a load index of 112 (maximum weight capacity of 2,755 pounds)
- Has a speed rating of T (maximum safe speed of 118 mph)
What are 2 types of tire sidewall marking on any tires?
There are several types of sidewall markings that can appear on tires, but two common types are:
- DOT number: This is a unique identifier assigned by the Department of Transportation and indicates that the tire meets certain safety and performance standards.
- Brand and model: This identifies the manufacturer and specific model of the tire.
What does 225 50 r17 on tires mean?
This tire size marking indicates that the tire is:
- 225 millimeters wide
- 50% of the width in height (aspect ratio)
- Designed for a 17-inch wheel diameter
- The “R” indicates that it is a radial tire
The load capacity and speed rating would be indicated by other markings on the tire.
What are some common tire marking mistakes?
Some common tire marking mistakes include:
- Incorrect tire size or load capacity information
- Mismatched speed ratings or load indexes
- Faded or worn markings that are difficult to read
- Missing or incomplete information, such as the UTQG rating or DOT number
- Poor quality markings that are smudged or incomplete.
There you have it. I hope by understanding tire markings with their reference, you can ensure your vehicle is equipped with the right tires for safe and reliable driving. Happy cruising!
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Hi there! I’m Naomi O’Colman. I’ve got years of experience working at an auto repair shop here in Texas under my belt. On top of that, ever since I was a kid I’ve been passionate about the auto industry. Since I’ve joined the team at automotivegearz.com I’ve been enthusiastically sharing my passion and insights with my readers. I’m dedicated to delivering high quality content and helping you stay up to date with the latest automotive trends and products out there!