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4 wheel drive
On a 4 wheel drive vehicle, all 4 wheels can move the car, in contrast to a front or rear wheel drive car. Some vehicles have permanent 4 wheel drive, others have selectable 4 wheel drive. Driving power can be spread differently over the front and rear axle.
A, AO, AOE
This marking is found on the side wall of original tires supplied with Audi models. These tires have been developed and manufactured according to certain specifications and requirements of the car manufacturer.
Caution: Tyres marked AOE indicate emergency running properties, and may not be combined with other tyres marked A or AO, see Runflat. Please note: Tires with this marking can also be used with other vehicles.
A/T: All Terrain
Off road vehicles which are frequently used on rough terrain must be fitted with special off-road tyres. As the name suggest, all-terrain tyres get you through all kinds of surface, whether it’s mud, snowy forest tracks or a country road littered with potholes.
Please note: These tires come in both imperial and flotation dimensions.
These abbreviations stand for Aston Martin specifications. These tires have been developed and manufactured according to certain specifications and requirements of the car manufacturer.
B, B1, BC, BL
These abbreviations stand for Bentley specifications. These tires have been developed according to certain requirements of the car manufacturer. They are specially aligned to the manufacturer’s chassis and from part of the vehicle’s original equipment.
C-Type tire (commercial-rated)
The C-Type tire is specifically meant as a commercial-rated tire, with a higher load rating for a given size than many LT tires. These C-Type tires will show the letter “C” immediately after the wheel diameter in the tire code. Example: 225/75R16C. Reinforced tires for light lorries. Depending on the manufacturer, the “C” stands for “Commercial” or “Cargo” but they both relate to the same thing. On many C tires there is a double marking for the maximum load for single or twin tire formations.
H/T: Highway Terrain
Highway Terrain (H/T) tires were developed to give the driver the best possible conditions on both wet and dry road surfaces. They are characterised by excellent comfort, low road noise and optimal driving properties.
What makes HT tyres special is they can also be used well off-road to a certain extent. Performance has been optimised for roughly 20% off-road and 80% on-road. These tires are a good option for anyone who takes their SUV into the woods now and again, or occasionally goes off-road.
M/T: Mud Terrain
Mud Terrain Tires are designed to perform most specifically in the mud. But when you look at the tread design of many mud tires, they generally perform well in other conditions such as on the rocks, in deeper snow, as well as in loose gravel and in the softer, constantly changing terrain of wooded trails. This is because mud tires are usually designed from a softer compound with wider gaps (voids) between the lugs, which grab onto anything it can hook one of its lug edges around, especially when aired down. Tread designs typically are what make or break a mud tire and vary widely from manufacturer to manufacturer. Drawbacks of the MT Mud Terrain tire are they perform poorly on the highway especially in the rain where the wide lug pattern results in less of a tire footprint on the road. Even worse, the MT can be downright dangerous in icy conditions. Mud tires also tend to wear quicker than an all terrain or a street tire and depending on your perspective, the on-highway noise level can be considerably higher especially after they wear down with highway use.
RunFlat, RFT, RSC, SSR, DSST, ZP, RF, HRS, ROF, EMT, TD, MOE, MO Ext. RunFlat tires (manufacturers use a variety of names) are tires with emergency running properties, which allow the motorist to keep driving for a limited distance when tire pressure is lost and / or tire pressure is too low. However, the vehicle must also be fitted with a TPCS. The runflat system works with a reinforced side wall which more or less keeps its shape in the event of a loss of pressure. These means the driver can keep control of his vehicle if pressure is suddenly lost. Travelling at max 80 km/h, he can then look for the nearest tire specialist within a radius of 80 km. RunFlat technology offers the driver a clearly recognisable benefit, and a real plus in safety and comfort. In addition, you don’t have to change the wheel when you have a flat, removing any need for a spare wheel. All runflat tires have the common RSC (RunFlat System Component) symbol on their sidewall.
At high speeds on wet roads, a water wedge forms between the tires and the road. The tires lose contact with the road and the vehicle no longer responds to steering movements. This phenomenon is called aquaplaning or hydroplaning.
Aluminum wheels (sometimes called alloy wheels) are built with a blend of aluminum and nickel. The majority of wheels today are cast aluminum alloy, meaning they’re made by pouring molten aluminum into a mold.
In contrast to steel rims, alloy wheels are available in almost any size or width. They are lightweight but strong, withstand heat well and are generally more attractive than steel wheels. They come in a very wide variety of finishes and sizes.
An Asymmetrical tire has a tread pattern that is designed for two purposes. Asymmetrical tires have one side of the tire that is designed entirely different from the other side of the tire. Asymmetrical tires will always have a marking to identify which side of the tire should be mounted facing out.
The section of the tire that sits on the wheel. Inside, there is a round hoop of steel wires, wrapped or reinforced by body ply cords, that clamps the tire firmly against the wheel rim.
Bead of the tire
см. англ. Beads
Tire load index or tire load rating is a numerical code on a tire sidewall which specifies the maximum load the tire can carry when inflated at its maximum permitted cold pressure, under certain service conditions - specified by the manufacturer.
The load index is identified as a part of the tire size designation or the tire's service description, together with the speed index. E.g., tire size designation: 205/60R15 91V - 91V in "service description" means this tyre can carry maximum load of 615 kg/1356 lb(load index is 91) and it sustains the maximum speed of 240 kmph/149 mph(speed index is V).
Tires with the same load index, regardless of tire size, may carry the same load, but not always, and they may require substantially different inflation pressures. An equal or greater load index does not always correspond to equal or greater load capacity at all inflation pressure settings, particularly when comparing P-metric and Euro-metric passenger car tires.
Light truck tires mostly use the term Load Range that is marked on a tire with a letter, to denote the maximum load carrying capacity of the tire.
How to Find the Load Index on a Tire?
Load index chart
An alphabetical code (A-Z) assigned to a tire indicating the range of speeds at which the tire can carry a load under specified service conditions.
Tire speed rating table for passenger cars:
|Speed Symbol||Speed (kmph)||Speed (mph)|
|(Y) (ZR**)||> 300||> 186|
For tires with a maximum speed capability higher than 240 km/h (149 mph), a "ZR" may appear in the size designation. Tires with a maximum speed capability higher than 300 km/h (186 mph), require a "ZR" in the size designation. Consult the tire manufacturer for maximum speed when there is no service description.
When marking tires, in addition to the name of the tire model and its size, the tire speed rating and the tire load index are indicated.
Where can you find your tire speed rating?
How to Find the Speed Rating on a Tire?
You can find your tire speed rating in a number of places, typically in the owner’s manual, driver’s side doorjamb. If you’re reading your tire sidewall, the speed rating will be the last item in the character sequence in the tire’s size code. Below is an example of a the description on a tire’s sidewall: 215/65R15 91V. Here, the tire would have a speed rating of V. V-rated tires can be driven at 240km/h / 149 MPH.
- 215 = Section Width in Millimeters
- 65 = Aspect Ration
- R = Radial Construction
- 15 = Rim diameter in Inches
- 91 = Load Index Service Description
- V = Speed Symbol
Tires having a maximum speed capability over 149 MPH may have “ZR” in the size designation. Tires with a maximum speed capability over 186 MPH are required to include “ZR” in the designation. Below are examples of tire sizes with a “ZR” speed rating.
ZR Designation, example:
- P275/40ZR17 93W, maximum speed=270 km/h (168 mph)
- P275/40ZR17 93Y, maximum speed=300 km/h (186 mph)
- BLK Black tire sidewall.
- LT LIGHT TRUCK - Reinforced tires for commercial vehicles such as vans.
- REINFORCED(=RF) Reinforced - So called reinforced tires are specially strengthened tyres which are designed to carry heavier loads, for example on vans, small buses and off-road vehicles.
- LRO LOW PLATFORM TRAILER - low platform trailer.
- RRBL RECESSED RAISED BLACK LETTERS - Special design of side wall lettering, slightly raised black letters with recess.
- VSB VERTICAL SERRATED BAND - Specially designed side wall lettering which is serrated inside the edge.
- ORBL OUTLINED RAISED BLACK LETTERS - Special design of side wall lettering, with slightly raised black contoured letters.
- ZR - indicates that the tire is suitable for speeds over 240 km/h, but not does state definitively what speed, at what load and tyre pressure.
- BSW BLACK SIDE WALL - Special design of the side wall. Tyres with a black side wall.
- OWL OUTLINE WHITE LETTERS - Special design of side wall lettering, with white contoured letters.
Reinforced tire marking:
- SSR RUNFLAT (Self-Supporting Runflat Tire) - developed by Continental. The tire has a special rubber reinforcement in the side wall, which takes on the weight of the car in the event of a loss of pressure in the tire.
- MFS MAXIMUM FLANGE SHIELD - The system of maximum bead rim protection protects tires from damage on curbs and sidewalks - a rubber profile located on the lower part of the wall above the rim flange forms a buffer zone.
- RF RUNFLAT is a technology that allows your car to keep moving after a puncture or flat tire.
- RUNONFLAT RunOnFlat tyres, formerly known by the acronym EMT, allow you to continue driving with partial or complete loss of pressure.
Tires for cars of some brands are marked with special symbols:
- NO, N1, N2, N3 - Tire designed for Porsche vehicles.
- J - Tire designed for Jaguar vehicles.
- MO - Tire designed for Mercedes vehicles.
In addition to the above, there may be other symbols on the sidewall of the tire that carry a lot of useful information:
- TUBE TYPE - Tubular design (mandatory use of a tire with a tube).
- TUBELESS - Tubeless tire construction.
- ML - Tire with rim protection for Mercedes or Audi.
- С - Reinforced tire.
- FR Flange Rotector - tire with rim protection.
- EMT - RUN FLAT by Goodyear.
- ALL STEEL - Tire with steel cord breaker and carcass.
- REGROOVABLE - Regrooving of the tread pattern is allowed.
- TREADWEAR 380 - Wear coefficient, determined in relation to the "base tire", for which it is equal to 100.
- TRACTION A TEMPERATURE A TREADWEAR 200 - traction, heat and wear ratings according to US Department of Transportation classification standards.
- TOUS TERRAIN - All season tire. R + W Road + Winter - road + winter (universal) tire.
- RETREAD - Retreaded tire.
- RADIAL - A tire with a radial design.
- TRACTION A - Traction coefficient. It has the values A, B, C. Tires with coefficient A have the highest amount of grip in their class. E17 The tire complies with European standards (the presence of a European homologation certificate, the number indicates the country).
- INSIDE or SIDE FACING INWARDS - The inside side of a tire with an asymmetric tread pattern (this inscription is inward).
- OUTSIDE or SIDE FACING OUT - The outer side of the tire installation with an asymmetric tread pattern (this lettering is facing out).
- PLIES: TREAD - Tire tread compound.
- SIDEWALL - Tire sidewall ply composition.
- MAX LOAD - Maximum load, kg and lbs.
- MAX PRESSURE - Maximum inflation pressure in the tire, Kpa and PSI.
- RIGHT - A tire with an asymmetric tread pattern that fits on the right side of the vehicle.
- LEFT - A tire with an asymmetric tread pattern that fits on the left side of the vehicle.
- ROTATION - Direction of rotation of a tire with a directional tread pattern (which has an arrow on the sidewall of the tire showing the direction of rotation of the tire).
- DA (stamp) - Minor manufacturing defects that do not interfere with normal use. There may also be an additional speed limit stamp, for example, no higher than 140 km / h.
- TEMPERATURE A - Temperature setting. An indicator that characterizes the ability of a tire to withstand temperature effects. It is divided into three categories - A, B and C. M + S (mud and snow), Winter (winter), Rain (rain), Water or Aqua (water), All Season Tires designed for use in specific weather conditions.
- TWI D - Projector wear indicator pointer. The indicator itself is a protrusion at the bottom of the tread groove. When the tread wears down to the level of this ridge, it's time to change the tire.
- DOT - Tire certification according to US Department of Transportation requirements. Includes several codes and contains information about the manufacturer, design and size of the tire.
- MADE IN ... - The country of origin of the tire.
- Stud - Studded wheel.
Anti theft lug nuts / bolts
An anti theft lug nut or bolt is a wheel nut or bolt which protects the wheel from theft. It can only be unscrewed with a special key.
Steel wheels are made with an alloy of iron and carbon. They are heavier than aluminium wheels but they’re more durable and can be easier to repair and refinish. Because of the way they’re made — cut out on a press and welded together — they don’t offer all the aesthetic spoke choices of other wheel types.