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Tyre & rim ABC

Here you find everything you always wanted to know about tyres, rims or accessories from A to Z. If you would like us to explain further terms, please send us an e-mail to info@reifen.com.

A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z


Is the abbreviation for "General Operating License". Every motor vehicle requires an ABE for registration in road traffic. The rules are regulated in the Straßenverkehrs-Zulassungs-Ordnung (Road Traffic Registration Act, short StVZO). The ABE expires if you make changes (tuning) and do not have them accepted by the TÜV (German MOT) and entered in the vehicle documents.

ABE Approval – Rim
The General Operating Permit (ABE) allows you to put the rims into operation without an examination at an examination centre. An ABE rim has comparable characteristics to an OE rim (Original Equipment) and has already been presented to the TÜV by the rim manufacturer. You only have to carry the ABE (General Operating Permit according to § 20 of the StVZO) in the vehicle.

Attention: In the expert opinion you will be informed about exceptions (e.g. A01). The registration / acceptance is then only necessary for certain vehicles mentioned in the ABE, e.g. if you use a different tyre size. Rims that do not have an ABE or ECE approval only have a technical component certificate according to §19(3) and must be registered accordingly. Acceptance by an expert is therefore absolutely necessary. You must have your vehicle inspected and registered at an inspection agency such as TÜV or DEKRA. The registration is subject to a fee.

When driving, braking and starting a car, both the surface of the tyre and the road surface are rubbed off. The softer a tyre, the greater the tyre abrasion. This also means that high levels of micro-rubber are released into the environment. It is therefore advisable to check and balance the tyre pressure regularly, according to the manufacturer's specifications.

Various factors can influence the tyre aging process: humidity, UV radiation, heat, cold, etc. In order to prevent a drop in performance, substances which greatly slow down the aging process are added to the rubber compound. After ten years, however, you should replace your old tyres with new ones.

The correct air pressure is crucial for the mileage and life duration of tyres as well as for driving safety. Too little pressure on the tyre can lead to unfavourable pressure distribution, overheating and even the risk of tyre bursting. In addition, the rolling resistance increases, which leads to an increase in fuel consumption. Regular tests show that only about one in four cars is on the road with sufficient air pressure. The information on the correct air pressure can be found in various places, for example in the description, in the owner's manual, on the B-pillar when the driver's door is open, on a sticker in the glove compartment or on the Internet in the tyre pressure tables of the manufacturers.

Independent tyre construction with balanced properties for both summer and winter conditions.

see All Season

The Three Peak Mountain Snow Flake (3PMSF) designation is awarded by the American National Highway Traffic Safety Administration (NHTSA) and identifies tyres which have achieved better traction on snow and ice than a reference tyre in a test. Tyres labelled in this way are tested for their snow properties in a standardized and globally recognized test procedure and must meet specified minimum requirements. These tyres perform particularly well in winter conditions - snow, icy roads and low temperatures - in terms of safety and driving control.

ABS is a braking system that allows the wheels to be held at full brake pressure just within the favourable slip range (10-30%) of the maximum static friction. To achieve this, several thousand control pulses regulate the brake pressure and ensure that the wheels do not lock. Thanks to ABS, flat spots no longer form during emergency braking. This therefore reduces tyre wear and the tyres can be driven longer.


  • shorter braking distances than with stutter braking, especially on wet roads
  • maintaining steerability (only turning wheels can build up lateral forces)
  • possibility to avoid an obstacle
  • braking in curves possible
  • stable braking behaviour on different surfaces

However, short braking distances can only be achieved in an emergency if full brake pressure is achieved by a merciless blow on the brake pedal. Nonetheless, ABS cannot replace safety distances that are too short, and unreasonableness remains dangerous even with ABS.

The driving characteristics of a motorcycle depend particularly strongly on the tyre used. This is especially true for powerful machines. Due to the high speeds that are allowed to be driven here and due to special legal conditions, tyre brand bindings for motorcycles are handled differently in Germany than in other European countries. Tyre bindings are largely unknown there.

For this reason, many motorcycle manufacturers issue so-called approval declarations or clearance certificates or expert reports, in which the tyre-vehicle combinations are listed. Using our model-related motorcycle tyre search, you will find an expert opinion link in PDF format in the detailed view of the selected motorcycle tyre, listing all approvals for the respective motorcycle. You will not find these PDF downloads for weaker motorized machines that do not require a separate expert opinion. Here it is only necessary to pay attention to the correct tyre values and dimensions.

Aquaplaning, (also known as water slipperiness), is the floating of the tyre on a wet road surface. The tyres can no longer "displace" the water masses and float up and thus become uncontrollable, unpredictable. Aquaplaning tips: avoid braking and steering. Take your foot off the accelerator and depress the clutch. Automatic drivers must never change gear under any circumstances.

see Traction Control System (TCS)


Applying weights to the rim to ensure that the wheel runs true. The greater the imbalance on the tyre, the more weights are attached to the tyres. Badly balanced wheels or unbalanced tyres cause the steering wheel to flutter and put excessive strain on the tyres, wheel bearings and wheel suspension.

Bar is a unit of measurement for the air pressure.

The bead - or inner ring of the tyre sidewalls - ensures a secure fit of the tyre on the rim. The bead core contains one or more wire cores with the surrounding carcass threads. The rubber apex is above the bead core. This way, tyre deformations caused by lateral forces, steering response and suspension comfort can be influenced.

A tyre with a too low inflation pressure will cause temperatures of up to 120 °C due to the increased flexing. This causes the material to partially overheat, especially in the shoulder area, which can cause parts of the tread to come off.

see Radial tyres

The bolt circle diameter is one of the most important dimensions of a wheel. The four or five holes or studs for fixing the wheel are arranged in a circle. Since vehicles are sometimes planned with different bolt circle diameters, the rim must be matched to them.

he braking distance is the distance travelled while the brake pedal is depressed and the vehicle comes to a complete stop.

The following factors influence the length of the braking distance:

  • Response time
  • Brake response time
  • Brake threshold time
  • Road condition (type, wetness)
  • Tyre condition (brand, tread depth, inflation pressure)
  • Speed

The braking distance is calculated using the following rule of thumb:

Braking distance = (driven speed in metres ÷ 10) x (driven speed in metres ÷ 10)

In the case of passenger cars/motorcycles, tyre brands and tyre types were listed by name in the vehicle documents. This meant that only these tyres could be used in the replacement purchase. This decision was repealed for passenger cars in February 2000.

The spare wheel will be history soon. According to statistics, a car driver has a flat tyre every 150,000 kilometres. What could be more obvious than to do without the spare wheel and at the same time build lighter cars and thus reduce fuel consumption?

This is where tyre manufacturers began many years ago and have worked intensively to develop new run-flat systems. With the new breakdown mobility concepts, it is possible to continue driving after a loss of pressure in the tyre and thus to reach the closest workshop. The speed and distance that can be driven depends on the system and manufacturer used. However, tyres with breakdown mobility have other decisive advantages over the conventional emergency wheel:

  • no tyre change on site
  • no dirty hands
  • no fixed wheel bolts
  • no search for a jack
  • no danger at the roadside

With high-quality belted tyres a defect is usually announced in advance. The tread blocks slam into the wheel arch and the handling appears spongy. Even in case of a sudden loss of pressure, a hectic reaction is always the worst solution and under no circumstances should the vehicle be braked brutally. The vehicle should rather be kept on the road by a sensitive counter-steering. To stop the vehicle, disengage the clutch and brake gently if necessary. If necessary, allow the vehicle to continue rolling to a suitable point. Switch on the hazard warning lights and set up the warning triangle at the latest when the vehicle comes to a standstill.


C stands for "Commercial" and refers to tyres with higher load capacity and reinforced base. The C marking can be found on the sidewall and in the vehicle documents. These tyres are found on trucks, vans, off-road vehicles, commercial vehicles and to partly also SUVs.

Camber is the inclination of a wheel or its centre line relative to the vertical to the road surface. If the wheel is inclined outwards at the top, the camber is positive (+); if the wheel is inclined inwards at the top, the camber is negative (-). As a result, the tyre contact surfaces are loaded on one side (inside or outside), which reduces the load capacity of the tyres.

This essential component of the load-bearing structure of the tyre gives the tyre its strength and ensures cohesion. Today, it mostly consists of synthetic fibres known as "rayon".

In the classic conversion process, we speak of replacing the standard tyres by newer tyres and rims. With the modern version, a conversion is also called tuning. Here the complete wheels are replaced by wider tyres and rims with an impressive appearance.

Cross-ply tyres are suitable for heavier loads because the sidewalls are stiffer. In cross-ply tyres, the carcass plies are made of nylon cord. They are laid crosswise on top of each other in the tread and sidewall at an angle of 55 degrees.
The cross-ply tyre offers the following advantages:

  • Higher resistance against damage to the sidewalls
  • Higher stability of the vehicle


Extreme caution is required when driving over nails, other metal objects or broken glass containers. Even the penetration of a foreign object into the tyre leads to a gradual loss of air. Do not underestimate penetrating moisture. This can then reach the belt and cause it to rust. This rusting can cause the rubber to detach from the belt and the tyre becomes a ticking time bomb.

Tyres with directional tread pattern are fitted in the direction indicated by an arrow. They offer the following advantages: Less noise, better wet traction, higher aquaplaning safety. High-performance wide and winter tyres in particular are increasingly designed as directional tyres.

The name-giving American "Department of Transportation" requires a number of details about the construction of the tyre, which are found in the form of numerical codes on the sidewall. Most often, however, this refers to the date of manufacture of the tyre. The age of the tyre is given in coded form. From the year 2000 onwards, the week and year of manufacture of a tyre are shown as four digits. This means that the last four digits indicate the week and year of manufacture of the tyre. The number combination "1320" means that the tyre was produced in the 13th calendar week in 2020.


The ECE certification mark (Economic Commission for Europe) or E-mark stands for components on motor vehicles that are subject to approval. The legal regulations stipulate guidelines for ECE marking. The marking also consists of a capital E in a circle and a test number related to the respective ECE regulation. This test number indicates that the marked components have been subjected to the necessary tests and approvals and an ECE type approval has been granted. Since 01.10.1998, E-marking has been mandatory.

ECE Prüfzeichen E4

ECE rims are rims which are considered to be non-registered throughout Europe. With the purchase of an ECE rim, it is possible to dispense with the requirement to carry an ABE (General Operating License according to § 20 of the StVZO) in the vehicle.

From a technical point of view, an ECE rim corresponds to an OE rim (Original Equipment). This essentially means that the offset and bolt hole design are identical to the OE rim. Deviations from the OE rim are only permitted in the design of an ECE wheel. Therefore, the advantages result from the fact that the original bolted connection can be used and that no TÜV (German MOT) registration is required or no ABE must be carried along.

The electronic differential lock is intended to brake a drive wheel spinning when starting off in a targeted manner up to a certain speed and thus transfer the excess power to the other drive wheel. Particularly with electronic accelerator pedals, the use of the electronic differential lock is often combined with a reduction in torque at the engine.

With the development of ABS regulation, the electronic differential lock also became possible. When the brake pedal is not depressed and the difference in speed at the drive wheels exceeds a set value, EDS ensures that pressure is directed to the faster spinning wheel and brakes it. Electronic differential locks are also suitable for four-wheel drive vehicles in light terrain. For larger requirements, the brakes can become too hot.

The Electronic Stability Control Program is intended to prevent the vehicle from swerving to the front or rear by the targeted use of individual wheel brakes.

ESP only works in connection with ABS. If the vehicle spins out at the front when cornering (understeering), selective braking of the rear wheel on the inside of the bend can initiate counter-steering. Braking the front outer wheel has the same effect when oversteering. In addition, the speed is reduced. For particularly sporty driving it can be switched off on some vehicles. The second-generation Electronic Stability Control Program is capable of braking several wheels simultaneously.

ESP cannot outwit the physical limits. Anyone who suddenly enters a curve that is too tight at high speed will continue to fly out. Braking one or more wheels does not help either.

There are various ways to maintain mobility in case of a breakdown:

  1. Classic spare wheel that is however used less and less.
  2. Emergency wheel, only used for a limited time and up to a maximum of 80 km/h.
  3. Folding wheel, like the emergency wheel. Additionally, with compressor for inflation and unfolding.
  4. Tyre sealant with and without compressor. (For passenger cars only with compressor).
  5. Self-supporting tyres (EMT, DSST). In the event of a breakdown, the side walls take over the supporting role of the air.
  6. PAX, with a new type of fastening of the tyre on the rim and with a support ring.
  7. CSR with support ring.

The latter versions (5-7) do not need to be stopped in the event of a breakdown, but may only be used in conjunction with an air pressure control system.

The tyre does not jump off the rim even in the event of a pressure loss and still allows a remaining range of up to 80 kilometres at a speed of max. 80 km/h - enough to reach the closest workshop or tyre dealer.

Emergency wheels allow you to continue your journey after a tyre damage. An emergency wheel is carried in the trunk. The spare wheel should only be used for short distances, for example to get home or to drive to a tyre dealer so that a new tyre can be fitted. In addition, you should only ride at a moderate speed, as a spare wheel never replaces an adequate tyre.

"Extended Mobility Technology" tyre with emergency running characteristics. Even after a complete loss of air pressure, EMT tyres can still cover distances of up to 80 kilometres at a speed of up to 80 km/h. Enough to safely reach the closest tyre dealer. This technology was developed by Goodyear.

see Electronic Stability Control (ESC)


Fitting of only two new tyres: The vehicle is stabilized via the rear axle. If there is a loss of grip on the rear axle, this leads to dangerous driving behaviour. For this reason, we recommend fitting two new tyres on the rear axle if only two new tyres are needed.

The periodic deflection of the tyre causes its deformation - the so-called flexing work, which releases heat and causes rolling resistance. If the air pressure is too low, the tyre overheats due to excessive flexing.

The footprint is the part of the tyre which maintains contact with the road surface while driving. The footprint is usually not much larger than the area of a postcard (guideline value applies to passenger car tyres), which emphasizes the tyre's high responsibility as a safety-relevant component on the vehicle.



High performance wide tyres with the designation HP (High Performance) or UHP (Ultra High Performance). These tyres often have a directional tread pattern, which may be indicated by an arrow. With these tyres, driving stability and steering precision are better. These tyres have special requirements in the high-speed range and convince with low noise. In addition, the safety during aquaplaning is very high and has better wet traction.

Summer tyres: For summer tyres, the speed index on the tyre must always be at least equal to the maximum speed of the vehicle, regardless of how fast the car is driven.

Winter tyres: May also be fitted if their speed index is lower than the maximum speed of the vehicle.

To determine the high-speed suitability, the tyre is tested on special high-speed test stands. The tyres are tested for their maximum permitted speed, whereby the speed is increased until the tyre is defective.

Important component of modern tyres. Denotes a bulge running all around the rim shoulder. Usually there are two humps on the rim contour (wheel inside and outside). These are intended to ensure that the tyre bead does not jump into the rim well under lateral load and insufficient air pressure.


Even minimal fluctuations in material density or other influences cause minor imbalances within the tyre. During the rotational movement this causes imbalances which can be compensated by counterweights on the rim. In addition, this increases wear and tear on the tyres, and driving comfort and safety are greatly reduced. If you notice an imbalance, you should contact your trusted tyre dealer as soon as possible.

Inch is an American unit of measurement (distance).
1 inch = 25.4 millimetres
1 millimetre = 0.03937 inch

The insertion depth is the distance between the wheel centre 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 is further inwards (i.e. towards the vehicle centre) than outwards.

To ensure that winter tyres literally "bite" into the snow, they have lamella-like edges and grooves that press the snow into a "toothed track". This creates an interlocking of tyre and road surface and provides optimum grip. Due to the toothing effect, significantly greater forces can be exerted, resulting in higher traction and shorter braking distances.




Fine incisions in the tread block, which act like small micro gripping edges. On winter tyres, for example, they increase traction when starting off and braking.

Lateral forces occur when driving in curves and leave no more room for longitudinal forces when braking. In a curve you should neither brake nor accelerate if possible.

A multi-digit number on the tyre sidewall, the so-called "load index", provides information about the load capacity, which varies according to vehicle weight for the same tyre size - for example, for small cars, mid-sized sedans or vans.

The load index is displayed as a number on the tyre sidewall. It is the penultimate value in the tyre designation. In the example illustration the tyre has the load index "91". You may also use tyres with a higher load index (= larger number, e.g. 95).

For vehicle tyres, the load index (also called load capacity index) describes the maximum permissible load per tyre.
List load index:


Index Weight in kg Index Weight in kg Index Weight in kg Index Weight in kg
19 77,5 45 165 71 345 97 730
20 80 46 170 72 355 98 750
21 82,5 47 175 73 365 99 775
22 85 48 180 74 375 100 800
23 87,5 49 185 75 387 101 825
24 90 50 190 76 400 102 850
25 92,5 51 195 77 412 103 875
26 95 52 200 78 425 104 900
27 97,5 53 206 79 437 105 925
28 100 54 212 80 450 106 950
29 103 55 218 81 462 107 975
30 106 56 224 82 475 108 1000
31 109 57 230 83 487 109 1030
32 112 58 236 84 500 110 1060
33 115 59 243 85 515 111 1090
34 118 60 250 86 530 112 1120
35 121 61 257 87 545 113 1150
36 125 62 265 88 560 114 1180
37 128 63 272 89 580 115 1215
38 132 64 280 90 600 116 1250
39 136 65 290 91 615 117 1285
40 140 66 300 92 630 118 1320
41 145 67 307 93 650 119 1360
42 150 68 315 94 670 120 1400
43 155 69 325 95 690 121 1450
44 160 70 335 96 710 122 1500

The tyre profile describes the ratio of sidewall height to tread width. The balloon tyre common in the 1920s with a height to width ratio of almost 1 : 1 has long since given way to the low-profile tyre (up to 0.25 : 1).


The M+S symbol (mud and snow) is a non-protected designation of a tyre whose tread pattern, tread compound or structure is primarily designed to achieve better driving and traction properties on snow than a tyre without the M+S symbol (EU Regulation No. 661/2009 as of July 13, 2009).

It should be noted that many tyre manufacturers also generally label summer tyres and off-road tyres, which are produced especially for the US market, with the M+S symbol.

A winter tyre can best be recognized by the M+S marking in combination with the "Three Peak Mountain Snow Flake” symbol as a distinction from M+S-marked summer and off-road tyres. This was decided on 31 December 2017, as the M + S mark is not legally protected.

Matching is the process of turning the tyre on the rim to minimize lateral and vertical run-out. To do this, the air is deflated and the tyre is pulled a quarter turn at a time until the best result is achieved.

The usage duration of a tyre depends on the vehicle, the driving style and many other factors. For front-wheel drive vehicles, the mileage of the rear tyres can be three times higher than that of the front tyres. As a general rule, the legal residual tread depth is 1.6 millimetres.

For cars, trucks and motorcycles, a minimum tread depth of 1.6 mm applies throughout Europe. This minimum dimension must be maintained over the entire tyre surface. If a tyre approaches this legally prescribed minimum tread depth, the braking distance in the wet and the risk of aquaplaning increase. A tyre with a minimum tread depth of 1.6 mm will double the braking distance in aquaplaning compared to a new tyre.

For safety reasons, summer tyres should be replaced when the remaining tread depth is less than 3 mm, and winter tyres when the tread depth is less than 4 mm.


Mixed tyres are defined as the mixture of different manufacturers, the tread depth or the combination of summer and winter tyres.

What is allowed and what not? It is allowed to combine summer and winter tyres, as well as all-season and winter tyres. The combination of different treads, tread depths and different manufacturers is also allowed, as well as a mixture of run-flat tyres and standard tyres, as well as emergency wheel and standard tyres. It is not allowed to combine cross-ply and radial tyres, or to combine different sizes and widths, rather it is only allowed to use different tyres if a type approval for this is noted in the vehicle documents.

However, any mixed tyres have a negative influence on the driving stability of the vehicle. This is particularly evident in the case of aquaplaning, braking or cornering.

The driving characteristics of a motorcycle depend particularly strongly on the tyre used. This is especially true for powerful machines. Due to the high speeds that are allowed to be driven in Germany and due to special legal conditions, tyre brand bindings for motorcycles are handled differently here than in other European countries. Tyre bindings are largely unknown there.

For this reason, many motorcycle manufacturers issue so-called approval declarations or clearance certificates or expert reports, in which the tyre-vehicle combinations are listed.

By using our model-related motorcycle tyre search, you will find a link to an expert opinion as PDF in the detailed view of the selected motorcycle tyre, in which all approvals for the respective motorcycle are listed. You will not find these PDF downloads for weaker motorized machines that do not require a separate expert opinion. In this case you only have to pay attention to the correct tyre values and dimensions.


All motorcycle tyres marked "NHS" (Not for Highway Service) are race-only products and may not be used on public roads unless the load index and speed category are also stamped on the tyre.

The noise emission of a tyre affects the overall noise level of the vehicle and influences not only its own driving comfort but also the noise level of the environment. In the EU tyre label, external rolling noise is divided into 3 categories, measured in decibels (dB) and compared to the European noise emission limits for external tyre rolling noise. The less black stripes the lower the external rolling noise measured in terms of the EU limit.


Off-road tyres are special tyres for off-road use. Off-road tyres have special properties such as notch-tensile strength for use off paved roads and off-road. The range includes mud chippers, sand specialists, all-rounders for off-road and road use, winter tyres, but also high-performance tyres for the road with the speed index W (up to 270 km/h).

Different tyre types:

All-terrain tyres are designed for both on-road and off-road use (50% road, 50% off-road). The abbreviations ATR, AT2, A/T or All-Terrain are used in the tyre designation.

Highway-terrain tyres (80% road, 20% off-road) are marked with the symbols H/T and S/T. These tyres are mainly used with asymmetrical tread patterns, which offer excellent driving characteristics on both dry and wet roads.

Mud-terrain tyres are tyres for difficult terrain (80% off-road, 20% on roads). These models are marked with the abbreviations MTR or M/T.

Driving behaviour in which the rear tyres lose grip prior to the front tyres: The car breaks away with the rear end and turns in a corner.


The tread pattern consisting of tread negatives (grooves) and tread positives (tread blocks) is designed to drain water or slush - on dry surfaces, a treadless slick would offer optimum grip.



Deviation from the run-out of the tyre in horizontal or vertical direction. Harmonization is only necessary in extreme cases of radial run-out - which is virtually non-existent in today's products. In this case, a special machine is used to reduce or completely eliminate the radial run-out by milling off the tread rubber.

The fabric layers of the carcasses of radial tyres are made of steel. The steel cord plies are applied vertically, making the sidewalls more supple.
The radial tyre offers the following advantages:

  • Higher driving comfort (due to flexible sidewalls)
  • Higher mileage
  • Better steering behaviour
  • Hard running surface is less sensitive to damages
  • Better wet grip
  • Lower heat generation

see TPMS (Tyre Pressure Monitoring System)

Designation on tyres with particularly high load capacity (e.g. for pick-up trucks, minibuses, vans, off-road vehicles, fast passenger cars with V-tyres). However, the decisive factor here is also the correspondingly higher load index number. Reinforced tyres of a certain dimension also require a higher inflation pressure than the standard version of the tyre.

Retreading is the application of a new tread to an old tyre. The tyres are either vulcanised in heating moulds (hot retreading) or heated together in autoclaves (cold retreading). Each tyre dimension has its own heating time.

The internationally used size specifications for rims - for example 7 J x 15 - describe the wheel width from rim flange to rim flange, here seven inches, and the diameter, here 15 inches.

The easiest way to find out which rims are suitable for your vehicle is to check the corresponding entry in your vehicle registration document. Please note that most cars have different tyre sizes for summer and winter tyres and that the rims must therefore be adjusted accordingly.

The distance covered from any point on the tread during one-wheel rotation. Thus, the rolling circumference is dependent on the tyre diameter; it has an influence on the gear ratio and the speedometer drive. Starting from the standard tyre, a tyre with a smaller rolling circumference tends to have a shorter gear ratio. Acceleration is influenced favourably, but at top speed the rev counter could be in the red area. In addition, the smaller tyre gives a greater speed advantage. Tolerances of plus 1.5 % and minus 2.5 % are acceptable. In case of larger deviations, at least a correction of the speedometer display must be made.

With lower rolling resistance, less energy is required, so less fuel is consumed and less CO2 is emitted. A high rolling resistance of a tyre therefore also means increased fuel consumption. This tyre characteristic is also listed on the EU tyre label for each tyre. The fuel efficiency is classified in seven classes: from A (highest efficiency) - G (lowest efficiency), whereby class D is not assigned. An improvement from one class to the next more efficient class means a saving of approximately 0.1 l of fuel per 100 km.

A tyre consists of a variety of rubber mixtures. However, tyre manufacturers always keep the exact composition to themselves. The rubber mixture is crucial for the quality of the tyre and to obtain a good tyre, many demands are made on the rubber mixture:

  • Low abrasion
  • Tear resistance
  • Slide resistance
  • Low rolling resistance
  • Dynamic resistance
  • Air tightness
  • Resistance to aging

Run-flat tyres can continue to run even after pressure loss. With a run-flat-tyre about 80 km can be driven with a maximum speed of 80 km/h. Run-flat tyres have sidewalls that are about twice as thick as a standard tyre, and are also known as "run on flat" or "self-supporting run-flat tyres".

Manufacturer abbreviations:

  • Bridgestone: RFT (Run-Flat-Tyre)
  • Continental: SST (Self Supporting Tyre)
  • Dunlop: DSST (Dunlop Self Supporting Technology) or ROF (RunOnFlat)
  • Goodyear: ROF (RunOnFlat)
  • Hankook: HRS (Hankook Runflat System)
  • Michelin: ZP (Zero Pressure) or SST (Self Supporting Tyre)
  • Pirelli: Run Flat, for some models Eufori@

This refers to tyres that have a self-supporting construction. This involves reinforcing the base, modifying the carcass and belt, and stiffening the sidewalls and bead area. These tyres can be driven over longer distances without pressure and can be mounted on conventional rims. However, a functioning air pressure control system is mandatory. These tyres can have the following designations depending on the manufacturer:

  • EMT, ROF = Goodyear
  • DSST = Dunlop
  • ZP = Michelin
  • SSR = Continental
  • Run Flat = Bridgestone

Tyres with run flat characteristics may only be used with a pressure monitoring system. There are two different systems:

  • Steering via ABS
  • Steering via sensors (that are mounted in the rim base or valve)


Uneven wear of the shoulder tread blocks leads to sawtooth formation and an increase in the noise level.

All self-supporting tyres have a reinforced base compared to conventional tyres. This is reflected in a modified carcass and belt area, stiffened sidewalls and bead zones. The advantage of reinforced sidewalls is the avoidance of direct and immediate contact between the rim and the inside of the tread, which leads to rapid destruction of the tyre. Furthermore, the tyres can be fitted on conventional rims. Thanks to the sidewall reinforcements, the tyres can also be driven without pressure over longer distances (at 80km/h this can be between 80 and 500 kilometres, depending on the manufacturer's recommendation).

An imbalance of 10g on the wheels acts like 2.5kg due to the centrifugal force at a speed of 100km/h. At 200km/h it is 10kg already. Tyres, wheel bearings and wheel suspension are thus put under excessive strain. Therefore, balancing should not be omitted during installation.

In case of speed-dependent vibrations or wobbling of the steering wheel the wheels should be rebalanced.

The sidewall is a very sensitive part of the tyre and influences the driving characteristics and comfort. A defect caused by improper use can only become apparent after months or years.

In addition, depending on the intended use of the tyre, some manufacturers go and fit the outer wall with a rim protection strip.

The sidewall is the side wall of the tyre. It influences driving characteristics and comfort. The sidewall contains all the tyre's markings, the tyre size, manufacturer and product name, speed index and date of manufacture.

The sidewall height is in relation to the tyre width. This means that for a tyre size of 175/70 R 13 S, the value 70 (70% of the tyre width) indicates the height of the tyre. We are talking about a 70ies series tyre. There are currently series from 80 to 25. From a value smaller than 55 we talk about wide tyres.

On the sidewall you can find all the information about the tyre. For example, there are details of size, type, manufacturer's date and speed class. A tyre designation has to do directly with the sidewall. Here the height of the tyre in relation to the tyre width is meant. For the designation 195/70, the 70 indicates that the height of the tyre sidewall is 70 percent of the tyre width. We then talk about a 70ies tyre.

Precipitated silica, in combination with a special type of rubber, enables a rolling resistance reduction by up to 20 %, good wet performance and high mileage.

The tyres and rims must not come too close to the body, nor must they touch chassis components such as brakes and track rods.

In extreme snow and track conditions, which even winter tyres cannot cope with, snow chains offer the possibility of reaching the finish line. Ten snow chain tips:

  1. Chain mounting is not possible with several wide tyre sizes due to space restrictions.
  2. Prior to the purchase, make sure that the chain size can be combined with the actual tyre and rim.
  3. Practice chain fitting at home in any case.
  4. Be careful when combining chains and light alloy wheels. With some types of chain, damage to the rim is possible.
  5. Always fit chains on the drive wheels, with four-wheel drive usually on the front wheels. If in doubt, contact the vehicle manufacturer.
  6. When driving with chains, the chainless wheels have considerably less lateral guidance and lock earlier when braking.
  7. Do not exceed the maximum speed of 50 km/h with chains.
  8. On roads free of snow, remove the chains as soon as possible.
  9. Rinse the chains with hot water after use and let them dry (also stainless steel products).
  10. For expensive chains it is worthwhile to have them repaired by the manufacturer. They can also be adapted to other tyre sizes.

The speed index is displayed as a letter on the tyre sidewall. It is the last value in the tyre designation. In the example illustration, the tyre has the speed index "H". You may also drive tyres with a higher speed index (= alphabetically ascending, e.g. V).

The speed index indicates the maximum speed at which the tyre can be driven at the most. Higher indices may of course be used.

Exception for winter tyres: the use of tyres with a lower speed index is permitted, provided that a clearly visible sticker showing the maximum permitted speed of the tyres is placed in the driver's field of vision. In this case the driver must not exceed the maximum permitted speed.

Speed index list:

Speed index max. Speed in km/h
A8 40
B 50
C 60
D 65
E 70
F 80
G 90
J 100
K 110
L 120
M 130
N 140
P 150
Q 160
R 170
S 180
T 190
U 200
H 210
V 240
W 270
Y 300
ZR >240

A tyre for dry roads, high temperatures, relatively high to very high speeds with corresponding temperature loads, and damp and wet roads.


The Three Peak Mountain Snow Flake (3PMSF, Alpine symbol) is awarded by the American National Highway Traffic Safety Administration NHTSA and identifies tyres which have achieved better traction on snow and ice than a reference tyre in a test. Tyres labelled in this way are tested for their snow properties in a standardized and globally recognized test procedure and must meet specified minimum requirements. These tyres perform particularly well in winter conditions - snow, icy roads and low temperatures - in terms of safety and driving control.

The toe is the distance between the tyre centres of an axle and can differentiate between the front and rear axles. Poor toe adjustment leads to uneven wear and poorer handling.

Tyre pressure monitoring system (short TPMS, in German RDKS) “means a system fitted on a vehicle which can evaluate the pressure of the tyres or the variation of pressure over time and transmit corresponding information to the user while the vehicle is running” (chapter I, article 3, point 7 of the EU Regulation 661/2009).

This technical monitoring of tyre pressure in everyday life makes sense as many tyre damages are caused by pressure loss, which is often noticed too late by the drivers of the vehicles. A tyre pressure that is too low leads in turn to higher fuel consumption and poorer driving behaviour, closely linked to this is an increase in tyre temperature as well as greater wear - ultimately, tyres can suddenly burst due to insufficient tyre pressure, a major safety risk for all vehicle occupants!

Tyre Pressure Monitoring Systems shall minimize safety risks

TPMS have been in existence for many years, and in the USA they have been mandatory for monitoring the tyre pressure of new vehicles for some time. In Europe, too, there are legal regulations for TPMS, which are laid down in EU Regulation 661/2009 of July 13, 2009:

  • According to this, all new type-approved vehicles of category M1/M1G must be equipped with a Tyre Pressure Monitoring System (TPMS) since 01 November 2012 according to ECE-R 64.
  • Further, from 01 November 2014, all newly registered vehicles of class M1/M1G must be equipped with a Tyre Pressure Monitoring System (TPMS) in accordance with ECE-R 64. This vehicle category includes vehicles for passenger transport with a maximum of eight seats in addition to the driver's seat, i.e. passenger cars, off-road vehicles and motor homes.

The legislator does not specify which type of TPMS (active/direct or passive/indirect) must be installed according to EU Regulation 661/2009 of July 13, 2009 - provided that TPMS comply with ECE-R64, active/direct and passive/indirect TPMS are permitted.

We support active Tyre Pressure Monitoring Systems

Our offered tyre pressure monitoring sensors support active TPMS. Active TPMS always consist of several components that work together on the vehicle and thus monitor the tyre pressure.

With an active TPMS, a programmed tyre pressure monitoring sensor is installed in each wheel, which also measures the temperature of each tyre in addition to the tyre pressure. These measured values are transmitted to a control unit in the vehicle (usually the vehicle's on-board computer) together with an individual ID of the tyre pressure control sensor while the vehicle is moving.

Active Tyre Pressure Monitoring Systems offer more safety!

Active TPMS with tyre pressure monitoring sensors work more precisely, because they can detect both slow diffusion losses and rapid pressure losses on a tyre. In a few years, active TPMS and tyre pressure monitoring sensors will be as much a part of a vehicle's equipment as ABS is today.

But despite this plus in safety, it should not be forgotten that TPMS and tyre pressure monitoring sensors do not automatically correct the air pressure or provide information about the tread depth of the tyres - tyres are the link between the vehicle and the road, and therefore it is important to continue to check the tyres regularly yourself or in one of our branches.

Note: As a standard, our complete wheel fitting is without tyre pressure monitoring sensor.

Please note that from November 1, 2014, all new vehicles of class M1/M1G (passenger cars, off-road vehicles and mobile homes) registered in the EU must have a TPMS.

If your vehicle has an active or direct TPMS with tyre pressure monitoring sensors, you can order tyre pressure monitoring sensors from us as additional equipment for certain vehicle models. This option will be indicated in the order process, if offered by us. Tyre pressure monitoring sensors ordered by you are fitted and programmed by us in the complete wheel and must be activated by you at the vehicle after receipt.

Should you have any questions about TPMS, our competent technical advisers are happy to help you personally.

Traction means "to pull, to drag". It describes the ability of a vehicle to convert the driving force of the engine into forward motion. The tyres are responsible for the forward movement of the car.

The traction control system (TCS, German ASR) of a vehicle prevents the wheels from spinning on smooth or uneven surfaces. Using electronic sensors, the power transmission to the drive axle is regulated so that the tyres grip smoothly and reliably when accelerating.

The tread has direct contact with the road surface and is responsible for power transmission together with the other tyre components. It must be able to transmit acceleration and braking forces in the longitudinal direction and lateral forces when steering and in curves. The quality of the tread is very much determined by the base (belt, carcass), the bead and side sections, but most decisively by the design of the tread pattern on the tread.

The performance level of a tyre in driving conditions - in wet or hot weather and in the transmission of lateral or longitudinal forces - depends largely on this. Even the mileage and noise behaviour are determined by the tread compound.

Tread pattern is the structure of a tyre on its tread. The tread pattern itself is a uniform pattern of a multitude of grooves and lamellas which vary according to manufacturer and product series. With the tread pattern designation, each tyre manufacturer assigns a model name to its specially developed tyre.

Abrasion indicators are integrated on the base of the tread and form narrow, continuous webs at a residual tread depth of 1.6 mm in the base of the tread. The position of these indicators is marked at the top of the sidewall - depending on the tyre manufacturer - by triangles, the letter combination TWI (Tread-Wear-Indicator) or small company symbols. The legal minimum depth in Germany is 1.6 mm. However, summer tyres should be replaced at a tread depth of 3 mm and winter tyres at 4 mm. This is because the lower the tread depth, the greater the risk of aquaplaning and the longer the braking distance.

These tyres can be identified by the tyre designation tubeless.

The age of the tyres is determined by two factors. Ozone from the atmosphere penetrates the tyre rubber in small quantities and affects the sulphur compounds between the rubber molecules. The rubber loses elasticity. Especially tyres which are stored unused harden and embrittle. This results in hairline cracks due to aging. Sun, wind and weather, but also contact with fats, oils and chemicals, can damage tyres.

Almost 100% of all tyre damages are due to improper handling of the tyres. Often a puncture is already pre-programmed if you pay too little attention to your tyres or if the tyres are overloaded in places. Only a regular visual inspection will reveal damage early on.

The cause of the most common defects:

  • Too little air pressure
  • Incorrect storage of the tyres
  • Damage caused by obstacles (e.g. kerbs)
  • Damages caused by foreign objects
  • Damages by high pressure cleaner
  • Damages by oil and fuel
  • Fitting error
  • Overaging

Nitrogen is also available for the inflation of tyres. This causes tyres to lose pressure more slowly under normal conditions as the diffusion speed of the nitrogen is lower compared to normal air. Tyres that are filled with tyre gas can be refilled with normal air at any time.

If you stick to the information in the vehicle registration document and pay attention to the tyre size, SI and LI, there is little you can do wrong when buying tyres from a specialist dealer.

However, problems with driving safety arise when mixed tyres are fitted, so this is not advisable.

Part of these are:

  • different brands
  • different degrees of wear
  • combination of summer and winter tyres
  • strongly differing tyre age

However, caution is still required for some time after fitting new tyres.

  1. There are often still abherents on the tread from the production process, which are only worn away after a few kilometres.
  2. The necessary fine roughness of the tyre surface is only achieved after about 200 kilometres on dry roads, which can take longer on wet roads and lead to dangerous slippage.

You can easily determine the right tyre size for your tyre purchase at reifen.com yourself. The tyre sizes for your summer and winter tyres can be different. You should therefore determine the correct tyre size on the tyres of the respective season. You can find all the necessary information you need on the tyres mounted on your vehicle. The correct tyre dimensions are also stored in your vehicle documents.


Driving behaviour in which the front tyres lose grip prior to the rear tyres: The car slides straight ahead in a direction tangential to the curve radius.


There are two types of valves: Rubber valves, which seal the rim hole itself and screw valves, which use a sealing ring for sealing.

Valves are very sensitive to dirt, dust and moisture. Therefore, the valve cap should always be screwed on tightly.

Valve breakage may occur due to overage, incorrect fitting or overload. It automatically leads to an immediate loss of pressure in the tyre.

The valve caps keep the valves free from dust, dirt and water. The life duration is thereby greatly increased.

Vulcanization is the station of tyre production. In the vulcanization press, the tyre blank not only receives its final appearance, but here the individual tyre components are also joined together through the targeted control of pressure and temperature at exact time settings and become elastic rubber. This takes place at around 165 to 200 °C and a pressure of 12 to 24 bar for around 9 to 17 minutes. However, it also describes a work step in tyre repair when the tyre has a hole or crack. Then it is not enough to just plug the hole, the tyre must also be vulcanized. In our branches we offer tyre repair, depending on the type of tyre / damage. This is not a tyre vulcanization as a vulcanizer would do. We would be pleased to advise you in a branch near you.


On wet surfaces, the positive blocks of the tyre must drain water through the drainage grooves. For example, at 80 km/h up to 25 litres of water per second are drained (at 100 km/h up to 31 litres, at 120 km/h up to 37 litres, at 140 km/h up to 43 litres, etc.)

The wear and tear depend on the aging of the tyres and on the driving. Tyre durability is determined by driving style, vehicle load, track conditions and maintenance (air pressure). With the same vehicle and tyre type, performance differences of several thousand kilometres are possible.

When braking in the wet, the tyre must be designed to evacuate water. Such a rapid evacuation will prevent aquaplaning.

The use of silica is an attempt to produce a suitable rubber compound for the tread which can achieve better wet grip. Wet grip is divided into classes A (shortest braking distance) - G (longest braking distance), with classes D and G not being used. The difference in braking distance from one class to the next better class is approximately between 1 and 2 vehicle lengths (3-6 m) in wet conditions at an initial speed of 80 km/h.

The weight of the vehicle bearing on the tyre.

Tyres suitable for winter use in the sense of the StVZO are tyres which are marked with the Alpine symbol. More details in our FAQs.

In addition to a special tread pattern with lamella and a larger number of negative blocks for good road grip, winter tyres are made of special rubber compounds to prevent the tread from hardening at cold temperatures.

Winter tyres in summer:
When driving with winter tyres in summer, the braking distance is extended by approx. 10 m at a speed of 100 km/h, which corresponds to approx. 3 vehicle lengths.




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