edition 8 ride control · 2 — the tyre is a component with a toroidal shape and made from rubber,...

THE UP-TO-DATE TECHNICAL INSIGHT IN AUTOMOTIVE INNOVATIONS

edition 8

8

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IN THIS ISSUE

TYRE TECHNOLOGY 2 TYRE PRESSURE MONITORING SYSTEM 9

INFLUENCE OF THE TYRE 3 TYRE SEALANT KIT 16WINTER TYRE 10RETREADED TYRE 16

CURRENT EU REGULATIONS 5 COMMON FAULTS 17RUN FLAT TYRES 13

STORAGE 15NITROGEN INFLATION 9

RIDE CONTROL

Tires

2 — WWW.EURECAR.ORG

THE TYRE IS A COMPONENT WITH A TOROIDAL SHAPE AND MADE FROM RUBBER, WHICH IS USED ON THE WHEELS OF A VARIETY OF VEHI-CLES AND MACHINERY. IT CONSISTS OF A MAIN-LY RUBBER COVERING CONTAINING AIR WHICH SUPPORTS THE VEHICLE AND ITS LOAD.TODAY, MOST PASSENGER VEHICLE TYRES, AS WELL AS THOSE ON LORRIES, ARE RADIALS AND THEREFORE COMPOSED OF AN ELASTIC TYRE TREAD, A PRACTICALLY INEXTENSIBLE BELT AND A RADIALLY ORIENTED ARCH STRUCTURE OVER AN INFLATED MEMBRANE AND SOME BEADS, ALSO INEXTENSIBLE, WHICH ARE COUPLED TO ANOTHER RIGID ELEMENT WHICH IS THE RIM. THERE IS ANOTHER TYPE OF TYRE KNOWN AS THE DIAGONAL OR BIAS-PLY TYRE, USED MAIN-LY IN LORRIES.

Nowadays, tyres are a mixed product, essentially made of rubber and tex-tile compounds with steel reinforcements. In order to manufacture a tyre the following materials are used:

1. Rubber (natural and synthetic rubber). . . . . . . . . . . .. . . . . . 41%

2. Fillers (carbon black, silica, carbon, chalk …). . . . . . . . . . . . 30%

3. Reinforcing materials (steel, polyester, rayon, nylon). . . . . . 15%

4. Plasticizers (oils and resins). . . . . . . . . . . . . . . . . .. . . . . . . .6%

5. Chemicals for vulcanisation (sulphur, zinc oxide, various other chemicals). . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6%

6. Anti-ageing agents and other chemicals. . . . . . . . . . . . . . . . . 2%

Materials used in a tyre

WWW.EURECAR.ORG — 3

INFLUENCE

OF

THE

TYRE

ON

THE

PERFORMANCE

OF

THE

VEHICLE

Tyre ComponentsA modern tyre is made up of:

Tread/belt assembly consisting of 1. Tread – ensures high mileage, good road grip and water expulsion2. Jointless cap plies – enable high speeds3. Steel-cord belt plies – optimise directional stability and rolling re-

sistance

Casing, consisting of 4. Textile cord ply – controls internal pressure and maintains the

tyre‘s shape5. Inner liner – makes the tyre airtight6. Side wall – protects from external damage7. Bead reinforcement – promotes directional stability and precise

steering response8. Bead apex – promotes directional stability, steering performance and

comfort level9. Bead core – ensures fi rm seating on the rim

INFLUENCE OF THE TYRE ON THE PERFORMANCE OF THE VEHICLE

Performance requirements of the tyre

• Capability of transporting load.• Suspension.• Transmission of the propulsion force of the engine. • Braking power.• Steering response.• Maintain handling.• Traction in all terrains (roads, mud, grass, stones, rocks, sand, ice,

snow)• Durability and dimensional stability.• Grip.• Side protection.• Puncture resistance.


Department of Transportation (U.S.A. department which oversees tyre safety standards)U.S. load rating for max. load (615 kg per wheel = 1356 lbs.)where 1 lb. = 0.4536 kgTread: beneath which there are 4 plies 1 polyester ply, 2 steel belt plies, 1 polyamid plySidewall: the tyre casing consists of 1 polyester plyU.S. limit for max. infl ation pressure 51 psi (1 bar = 14.5 psi)Information for consumers based on comparison values with standard reference tyres (standardised test procedures)Treadwear: relative life expectancy of the tyre based onstandard U.S. testing (as % of the value for the reference tyre)Traction: A, B or C = wet braking capability of the tyreTemperature: A, B or C = temperature stability of the tyre at higher test speeds. C is suffi cient to meet U.S. statutory requirementsIdentifi cation for BrasilIdentifi cation for China

Sidewall markings – standard and required by law

Manufacturer (trademark or logo)Product nameSize designation205 = Tyre width in mm55 = Height-to-width ratio in percentR = Radial construction16 = Rim diameter in inches (code)91 = Load index V = Speed index Tubeless radial tyreContinental tyres are marked in accordance with interna-tional regulations. So the sidewall is marked with a circle containing an E and the number of the country of homologa-tion. This marking is followed by a multi-digit homologation number, e. g. E4 e4 (4 = Netherlands)Manufacturer’s code: Tyre factory, tyre size and type Date of manufacture (week/year) 2013 means the 20th week of 2013T.W.I.: Tread Wear Indicator. A number of small raised bars run across the main grooves. The bars have a height of 1.6 mm and gradually become level with the rest of the tread as the tyre wearsCountry of manufacture. All other information applies to countries outside Europe:

123

4

56

7

8

9

10

11

12

13

1718

AbbreviationsDOT = U.S. Department of Transportation

ETRTO = European Tyre and Rim Technical Organisation, Brussels

ECE = Economic Commission for Europe (UN institution in Geneva)

FMVSS = Federal Motor Vehicle Safety Standards (U.S. safety code)

14

1516


There are rules relating to the tyre in different legal texts:Directive 92/23, Annex IV stipulates:• All tyres fi tted on a vehicle will have the same structure, for example, radial.• All tyres installed on an axle must be of the same type, make, structure and

category.

Royal Decree 736/1988, Article 6 of Annex 1 which refers to alterations stipulates:• The load rating has to be equal to or greater than the original tyre.• The speed rating has to be equal to or greater than the original tyre.• The outer diameter should be equal.Article 212 of the traffi c regulations, Section D stipulates:• The minimum legal tyre tread depth must be 1.6 mm.

CURRENT EU REGULATIONS

European tyre labelling

From 1 November 2012 European Union Regulation 1222/2009 on tyre labelling entered into force. This labelling is a new regulatory system for classifying tyres, and is applicable to tyres for 4x4 type vehicles, passen-ger vehicles, vans, lorries and buses. Retreaded, studded or competition tyres, among others, are exempt from the standard labelling. The regula-tions will allow three fundamental aspects to be assessed, assisting the consumer in recognising and seeing the difference between good quality and poor quality tyres.

The three parameters assessed are fuel consumption, wet grip perfor-mance and noise level. The label is similar in appearance to that used in today’s household electrical appliances, so that it is easier for the cus-tomer to understand.

Fuel ConsumptionFuel consumption: also known as energy effi ciency or rolling re-sistance. With lower rolling resistance, there is lower fuel consumption and, for that matter, increased energy effi ciency. To measure this rolling resistance, the tyre is mounted on a roller. The test simulates driving at 80 km/h with a load equivalent to 80% of the load rating of the tyre. The rolling resistance is measured in kilograms per ton (Kg/t).

Reduced rolling resistance saves fuel and CO2:• Consuming 6.6 l over a distance of 100 km equates to a saving of up to 1.5 l per class• This saves up to 6.6 l over a distance of 1,000 km

CURRENT

EU

REGULATIONS


SafetyWet grip performance: this test measures the degree of grip per-formance of the tyre to a wet surface. The test is performed by measuring the distance needed to go from 80 km/h to 20 km/h on a road covered with a fi lm of water with a depth of between 0.5 and 1.5 mm. Based on the results obtained, a rating is assigned to the tyres which varies between 1.09 and 1.55.

Grip in wet conditions is crucial for safety whilst driving:• The braking distance per class is 3 to 6 metres longer• The impact speed per class is up to 25 km/h higher• The difference in stopping distance between A and F is up to 18 metres• The difference in residual velocity between A and F is up to 49 km/h• A collision at 25 km/h equates to a fall from a height of 2.5 metres

Besides the three main criteria included on the EU tyre label, there are many more performance factors that go towards making a genuine pre-mium tyre. All the more reason to refer to other sources like tyre tests,manufacturers material and retailers recommendations in addition to the EU tyre label.

When it comes to winter tyres in particular, the EU tyre label is of limited signifi cance, because no information is given on winter properties such as traction in snow and braking on snow and ice.


CURRENT

EU

REGULATIONS

Noise LevelNoise level: this test measures the external noise level of the tyres. The test is performed by placing a microphone on the edge of the circuit to measure the noise level of a vehicle driving at 80 km/h. The noise level is measured in decibels (dB).

Speed rating

It is an alphabetical code corresponding to the maximum speed a tyre may reach. This information is shown on the side wall of the tyre.

Letter Maximum speed Letter Maximum speedL Up to 120 km/h P Up to 150 km/hM Up to 130 km/h Q Up to 160 km/hN Up to 140 km/h R Up to 170 km/h

S Up to 180 km/h

Letter Maximum speed Letter Maximum speedT Up to 190 km/h V Up to 240 km/hU Up to 200 km/h W Up to 270 km/hH Up to 210 km/h Y Up to 300 km/h

ZR >240 km/h

Test criteria EU tyre label Tyre testsWinter propertiesTraction in snow ●Handling ●Braking in snow/ice ●Dry conditionsDriving stability ●Handling ●Braking ●Wet conditionsAquaplaning longitudinal ●Aquaplaning lateral ●Handling ●Braking ● ●NoiseInterior ● ●Exterior ● ●Rolling resistance ●Wear ●High speed ●PAH oil level ●

Trust tyre tests:• Independent tests by magazines include more than three criteria,

which is why they remain an important source of information• Continental tyres have been occupying the top positions in these

tests for many years

The EU tyre label is of limited signifi cance:• Not all tyres with good EU tyre label values necessarily have good

test results• All criteria have to be considered when choosing a tyre


Load rating

Is a numerical code which corresponds to the maximum load that a tyre can support at a speed indicated by its speed rating under the

conditions specifi ed by the manufacturer. This information is shown on the side wall of the tyre.

Load rating kg Load rating kg60 250 74 37561 257 75 38762 265 76 40063 272 77 41264 280 78 42565 290 79 43766 300 80 45067 307 81 46268 315 82 47569 325 83 48870 335 84 50071 345 85 51572 355 86 53073 365 87 545

Load rating kg Load rating kg88 560 102 85089 580 103 87590 600 104 90091 615 105 92592 630 106 95093 650 107 97594 670 108 100095 690 109 103096 710 110 106097 730 111 109098 750 112 112099 775 113 1150100 800 114 1180101 825 115 1210

Basic rules of replacement/alterations

According to the current legislation, when replacing worn tyres with new ones, they must be equivalent tyres. This equivalence must meet the following conditions:• Equal or higher load capacity index.• Speed code equal or higher.• Outer diameter equal, with a tolerance of +-3%.Nevertheless, a different diameter rim can be fi tted and the tyre meas-

urements modifi ed. These equivalents are standardised by ETRTO (European Tyre and Rim Technical Organisation).

This organisation studies the possible theoretical equivalents for any tyre, using the maximum circumference of the OE tyre as a starting point and applying a margin of +/- 2 %.

Vehicle manufacturers approve different dimensions of tyre for a vehi-cle, which can be seen on the vehicle’s roadworthiness documentation.

Basic rules to follow for replacement or alteration

• Ensure that the load or speed rating of the replacement tyre is the same or higher than the tyre fi tted as standard.

• Remember that if the aspect ratio of the tyre is reduced, the section width increases.

• Ensure that the width and diameter of the rim to which the tyre is fi tted corresponds to the ETRTO recommendations.

• Ensure that the tyre selected for alteration does not interfere with any of the bodywork components or suspension, including the turning radius and load.

• Remember that additional space will be needed if you wish to fi t chains.

• Any alteration should respect the current regulations/legislation.


NITROGEN

INFLATION -

TYRE

PRESSURE

MONITORING

SYSTEM

-

TPMS

Nitrogen is an inert, non-fl ammable gas, therefore it is a much safer substance than oxygen in many situations. On the other hand, it is a dry gas compared to normal air, which is a wet gas, so it also helps to prevent oxidation of certain components in the wheel as well as the rims or steel belts covering the tyres, better preserving the properties and fl exibility of the rubber.This gas is found in the Earth’s atmosphere in the quantity of 78%, next to oxygen at 21% and other gases at 1%.Tyre infl ation with nitrogen improves the performance of the tyre, pro-longs its life and increases vehicle safety, with the following advantages:• The pressure in the tyres at the recommended levels is maintained

for a longer time.• Tyre performance improves as there is fi rmer grip of the vehicle’s

tyres to the road and reduced braking distance.• Greater fuel savings are achieved and as a consequence, CO2 emis-

sions are reduced.• Compatible with any type of tyre, regardless of the tyre measure-

ments.• Reduces the risk of blow-outs.• The tyres wear regularly and their life-span is extended.• Enables safer and more effi cient driving.• Oxidation/rust problems inside the steel rims are reduced.• Care of alloy wheels is improved.

It is always recommended to continue infl ating nitrogen infl ated tyres with nitrogen, as if they are infl ated with air, the nitrogen concentration will reduce and its advantages will diminish. In order to identify tyres infl ated with nitrogen, green-coloured valve caps are fi tted.

NITROGEN INFLATION

TYRE PRESSURE MONITORING SYSTEM TPMS

This is an electronic system for monitoring the air pressure inside the tyre of a vehicle in real time, warning the driver in the event of the loss of pressure of any tyre which may cause an accident. This system is part of the active safety system and is mandatory in vehicles manufac-tured since 2014. According to European Union legislation, the TPMS systems should have the following characteristics:

• Determination of the pressure loss at speeds from 40 km/h up to the maximum driving speed of the vehicle.

• Data transmission of 434 MHz.• Leak of pressure in tyres warning when the pressure is lower than 20

% in any of them.

Currently, there are two types depending on system operation:

Indirect tyre pressure monitoring system (iTPMS)

This system does not use physical sensors for determining the tyre infl ation pressure, but measures the pressure indirectly, based on the turn speed of each wheel and other values that are obtained externally. The iTPMS is usually integrated into the ABS control unit and compares the rotation speed of the tyres to determine whenever there is an error in the infl ation pressure. To do this, it uses the ABS system sensors to detect the tread circumference of the tyres. The circumference of the tyre will be altered when the tyre pressure goes down due to a puncture.

This altered circumference makes the affected tyre turn more than the tyres at the correct pressure. The ABS sensors detect this anomaly, and the ABS control unit sends the information through the multiplex network so that a light illuminates on the instrument panel and alerts the driver.

The iTPMS therefore provides relative values, and that is an inherent problem in the system. It does not identify that there is a problem in more than binary form. In addition, under low grip conditions it can send incorrect measurements if there are losses of grip with the road surface during driving.


Tyres that are designed to cope in low ambient temperatures on a wide variety of road conditions including dry, wet, snow and ice. The tyres carry a “Snow Flake on Mountain Peak” symbol on the sidewall (Typi-cally October to March)

Tyres marked M+S are designed for winter Mud and Snow. This does not specify any defi ned winter performance. Because most all-year tyres offer insuffi cient winter performance, a series of test conditions and minimum requirements have been specifi ed in the USA and are in-dicated by the “Snowfl ake on the Mountain” symbol. A tyre marked with the snowfl ake must offer a minimum 7% improvement in braking perfor-mance on snow vis-à-vis a uniformly defi ned standard reference tyre.

The fi rst prototypes of a special winter tyre for use on snow and ice was developed as early as 1914. The fi rst series-made winter tyres were launched in 1952. Early winter tyres had massive bars, they were loud, hard and, by today’s standards, only moderately suitable for winter use. Also, they could only be driven at relatively low speeds. The real market breakthrough for winter tyres came with the development of special tread compounds for winter service and modern sipe technology (fi ne slots in the tread). Ice, snow and low temperatures need not put motor-ists at greater risks on the road. By switching to winter tyres, one can still maintain a high margin of safety. When temperatures drop, winter tyres perform better than summer tyres.

The highly developed, specialized tread compounds used in sum-mer tyres are designed to provide the highest possible levels of grip at ambient temperatures above +7°C. When it gets cold outside, win-ter tyres give superior performance on wet and slippery roads. Winter tyres should be fi tted when the temperature drops below 7°C. It is not recommended to mix summer and winter tyres on passenger cars. In

most European countries, motorists are required to fi t only summer tyres or only winter (M+S) tyres to any one axle; in some countries this also applies to all four tyre positions. Winter tyres must satisfy certain requirements, such that the minimum legal tread depth of 1.6 mm is no longer suffi cient.

The tread pattern used on a winter tyre is particularly effective on snow and slush. In these conditions, the rotation of the wheel presses the snow into the wider grooves used on this type of tyre, thereby generat-ing additional traction. When setting off, rows of fi ne lateral sipes enable the tread blocks to fl ex and bite deeper into the ice or snow for better traction.

Winter tyres with a tread depth of 4 mm are at the limit of their winter capabilities. Tyre industry recommends a minimum tread depth of 4 mm for using winter tyres on wintry roads and identifi es this by means of a special winter tyre wear indicator that the tyre is equipped with in ad-dition to the 1.6 mm TWI. When the tread has worn down to a residual depth of 4 mm – regarded as the limit for winter suitability – the winter tyre wear indicator appears fl ush with the tread pattern surface.

All season tyres are by design a compromise between “Summer” and “Winter” tyres. They offer higher grip levels during the warmer months than winter tyres and better grip than summer tyres in the winter. How-ever they will not offer the same performance as Summer or Winter tyres in the seasons they are specifi cally designed for.

Direct tyre pressure monitoring system (TPMS)This system uses sensors placed inside the tyre to measure the pres-sure and temperature of each wheel, sending the recorded data by radio to a control unit which acts as a central receiver and manages the system. The system consists of:

Control unit for the TPMS: manages the system and receives information from the wheel sensors.

Wheel sensors: are located in the wheel’s valve. Its function is to measure the pressure and temperature of the tyres and send the infor-mation to the control unit for the TPMS. The information from the wheel sensors is sent to the control unit for

the TPMS on a radio frequency of 434 MHz. The control unit processes this information and sends it over the multiplexed network to the tyre pressure monitoring display which, depending on the vehicle, may be included in the dashboard.

Given that it is a system with practically no mechanical components, there is no maintenance required but there are two things which must be avoided:• Avoid any blows, as vibrations and strong impacts can damage the

sensors.• Check that the valve caps are in perfect condition.

It is very important that no liquid or dirt enters the valve mechanism, which may damage its leak-tightness and even the electronic sensor itself.

WINTER TYRE


WINTER

TYRE

ChainsSnow chains increase the tyre’s grip in snow or ice, as they are com-ponents which, generally, dig into the ice or snow-covered ground and allow the vehicle to move. They avoid the problems of the summer tyres of lack of grip, skidding, longer braking distance and poor handling.

They are fi tted temporarily and only when there is snow. It is not possi-ble to drive on a road with chains unless there is snow as this may dam-age the tyre and the rim, and also the chain itself or even the asphalt. There are four types of chains:• Galvanised steel chain.• Textile tyre chain or sock.• Composite or “mesh” type chain.• “Spider” or semi-automatic type chain.

The chains can be placed on drive wheels. If the vehicle is front-wheel drive they can be placed on the two front wheels. If, on the other hand, it is rear-wheel drive, the chains can be fi tted on the rear wheels. In both cases, if the snow is very deep, chains should be fi tted to the four wheels for greater safety.If the car is 4x4 wheel drive, chains should be fi tted to the four wheels, but if there is no other option, it is enough to fi t them to the front wheels to get out of trouble, as these are the directional and drive wheels.It is important to remember that when chains are fi tted, you should drive at reduced speed, normally at a maximum of 50 km/h. When the chains are removed and their use is no longer needed, it is advisable to rinse them with plenty of water to remove the salt from the roads and other debris which may rust or damage them, then allow them to dry before storing them.

Nordic tyresNordic tyres are designed for maximised ice grip properties as possible without studds. With this focus they offer also excellent snow grip. This deliberate design scope makes Nordic (or soft compound) tires the best choice when in winter time the roads are continuously covered with icy or hard pressed snow surface and will perform signifi cantly better than standard winter tires. This type of tyre is characterised by having a softer compound which remains fl exible also below - 20°C and ensures maximum possible ice grip among none studded tires. A higher number of sipes compared to standard winter tires enable even better grip on snow and ice.Nordic softcompound tyres are more effective than European standard winter tyres on wintery roads and very cold conditions. These tyres, as their name suggests, are mainly used in Nordic countries and in Japan. With the uncompromised focus on ice grip which is realised by soft compound the handling property on dry roads will feel also softer. However this has not been identifi ed as a problem by the users when high snow grip and max. ice grip is the priority in the Nordic regions with strong winter conditions. Nordic softcompound tyres are recommended for dedicated markets and not offered everywhere,

Note: in Japan the studdless soft compound tires are the only suffi cient choice in the North since studded tires be-came prohibited by law.

Studded tyres

These tyres are an alternative to European winter tyres in areas with strong winter condition when safe driving on icy roads is fi rst priority. They are required in the North of Scandinavia and in some regions in the alps. The use of studded tyres is clearly limited by legislation. The performance is best on completely frozen terrain. Not all countries permit their use, and those which do usually restrict it to certain times of the year. In Europe, they are permitted in Alpine countries such as Switzerland, Austria and Liechtenstein, and Nordic countries such as Sweden, Finland and Norway.


Galvanised steel chainsConsist of several galvanised steel links which are intertwined. There are usually two designs: cross-link chains and diamond chains; the lat-ter are the most common.

These chains usually include one or two manual tensioners for keeping the chain closely fi tted to the tyre. There are slightly more expensive variations with automatic tensioners. This type of chain works well on snow and ice. It is very durable and resistant.

The drawback is that this chain is somewhat more diffi cult to put on than other models, especially if you have no experience, and it is more noisy and uncomfortable as it transmits more vibrations through the steering and suspension. The links may brush against or scratch the alloy wheels and disorientate the operation of the vehicle stability assist control.

Textile tyre chain or sock This is basically a fabric cover for the tyre which is fastened with an elastic band on the inside and spokes or fabric on the outside.

They work well on snow and ice, with low erosion when compared to link chains, and in some situations they even perform better, for ex-ample when braking. They can also be fi tted and removed easily and quickly, and are lighter.

Another important advantage is that they have less of an impact on the steering and suspension, as they do not generate shaking or vibrations, and they do not affect the sensitivity and operation of the vehicle stabil-ity assist control.

The main disadvantage is that they are not as hard-wearing, as the fabric wears away very quickly, so they are for short journeys and oc-casional use, not for those who need to use them on many days of the year. When used on snow or ice there is no need to worry, but they cannot be driven on a road that is not snow-covered as they will wear out very quickly, in just a few kilometres.

Composite or “mesh” type chainConsists of a mesh fabric which strongly resembles textile chains. On the inside there is rubber which fastens the chain to the wheel and several spokes for fastening to the outside. The mesh is made up of a plastic cable on the inside and a fabric outer coating. The mesh is woven with steel links at the crossover points.This is a chain which functions very well on snow and ice, and is suf-fi ciently hard-wearing. It can also be fi tted relatively easily and quickly, except that the rubber is very tight and you will need strong arms.These chains have hardly any impact on the steering and suspension, generating very few vibrations. The vehicle stability assist control also operates without any problems. These chains are highly recommended to those using them many times over the course of the year.

“Spider” or semi-automatic type chain Usually has two parts, a disk which is always placed over the rim and fastened with screws, and then the chain itself which can be of several subtypes. The most well known is like a caterpillar-type with rigid trans-verse bands, but there are some with a mixed solution, with hard plastic chains and bands. With the disk in place, it can be fi tted very quickly. This is a chain which functions very well on snow and ice. These chains are for anyone who uses them often and in adverse conditions.


RUN FLAT TYRES

This type of tyre is reinforced and can be driven for a distance of approximately 80 km and at a speed not exceeding 80 km/h when there is a puncture.To fi t a Run Flat tyre, the vehicle must incorporate a specially manu-factured rim and have a tyre pressure monitoring system (TPMS).

Features• Possible to drive with punctured tyre(s)• Reinforced side walls• Vehicle control even without pressure• Run Flat winter tyres are also available

These tyres support the weight of the vehicle thanks to the ma-jor reinforcement of their sidewalls. Thanks to the special de-sign of their beads, roll-off is prevented. The bead is fi lled us-ing a special type of rubber which combats the build-up of heat.

An alternative technology which delivers extended mobil-ity is a sealant, e.g. ContiSeal. This is a sticky, viscous seal-ant layer. It is applied to the inside of the tyre in the tread area. In case of a penetration by foreign objects such as nails, there is no need for immediate roadside tire changes and holes re-main sealed even if the puncturing object becomes dislodged.

Technical Instructions• For optimal conditions, a Tire Pressure Monitoring System (TPMS) is

recommended.• It is not necessary to stop immediately for a tire change. Your journey

can be continued.• Upon discovering a puncture, a tire specialist must promptly check

the tire.

Distinguishing letters ManufacturerDSST DunlopEMT GoodyearHRFS HankookRFT BridgestoneRSC BMWSSR ContinentalSSRF PirelliTRF ToyoXRP KumhoZP MichelinZPS Yokohama

WINTER

TYRE

-

RUN

FLAT

TYRES

Run Flat Tyre:An SSR tyre has a reinforced sidewall which, in the event of a puncture, prevents the sidewall from being crushed and ensures the driver can continue driving for up to 80 km at a maximum speed of 80 km/h.

Standard tyre (Defl ated):When a puncture occurs with a standard tyre, the sidewall can become crushed between the rim and the road, leading to a dangerous situation like a blow-out or the tyre slipping off the rim.


STORAGE

New tyres which are properly stored and handled lose virtually none of their properties and characteristics even over a period of several years. When removing the tyre, one should make a note of the wheel position (by chalk marking the tyre “FL” for front left, for example). Certainly when it is time to change from summer to winter tyres, one

should use the opportunity to switch the wheels round (from front to back, and vice versa). This results in better economy, particularly in the case of vehicles with front-wheel drive. When changing the wheel position, always observe the recommendations in the car manual.

Tyre Storage

Tyre Storage Recommendations

These recommendations are intended for consumers, but they are also important for tyre dealers. For commercial applications of new and waste tyres (tyre dealers and fl eets), there may be more strin-gent and legal restrictions. Please check local regulations. Tyres are compounded to resist normal deterioration caused e. g. by sunlight, humidity and ozone. Nevertheless, stored tyres should be protected against these and other potentially damaging conditions. The longer

the storage period, the more exposure there is to potential dam-age. After dismounting from a vehicle the tyres should be thoroughly cleaned and inspected for damage. Remove all stones and debris from the grooves. Chalk marking the tyres with their wheel positions (FL for Front Left, RR for Rear Right, etc.) will help to fi nd the correct positions according the rotational plan.

General:• DO STORE TYRES where it is clean, dry and moderately venti-

lated.• Moist conditions should be avoided. Tyres destined for retreading /

repairing should be thoroughly cleaned and dried out before such operations are performed.

• DO STORE TYRES at temperatures not exceeding 35 ° C (95 F), preferable below 25 ° C (77 F). Direct contact with hot pipes and radiators must be avoided.

• Also deep temperatures below the freezing point might lead to brit-tleness and tyres should be carefully warmed up before mounting.

• DO STORE TYRES, if outdoors, protected by an opaque waterproof covering, but avoid creating a heat box or steam bath. Ensure proper ventilation.

• DO STORE TYRES, if outdoors, where tyres are raised off the stor-age surface.

• AVOID STORING TYRES on piers, ship decks, or other unprotected areas.

• AVOID STORING TYRES, where they can be damaged by passing objects – lawn mower, bicycle, or garden tools.

• AVOID STORING TYRES where the area is wet, oily, and / or greasy such as with gasoline or petroleum-based products. Also, do not store on or against sensitive surfaces where staining can take place.

• AVOID STORING TYRES in the proximity of chemical agents like solvents, fuels, oils, hydrocarbons, paint, acids, disinfectants, etc.

• AVOID STORING TYRES where subject to extreme temperatures, direct sunlight or artifi cial light with a high ultra-violet content. Room lighting with ordinary incandescent lamps is preferable to fl uores-cent tubes. Never store them near battery chargers, ovens, or open fi res.

• AVOID STORING TYRES on black asphalt or other heat absor-bent surfaces and on highly refl ective surfaces (i. e., sand or snow covered ground).

• AVOID STORING TYRES in the same area as an electric motor or other ozone generating source. If there is a doubt, check ozone levels to be sure they do not exceed 0.08 ppm.

• Do not use tyres as a workbench or tool stand. Soldering irons,

power drill and tools can damage a tyre. Never put a burning ciga-rette on a pile of tyres.

• Do not store other items on top of a tyre, especially where staining of the surface would be a concern. Loose tyres or tyres mounted on rims, but not installed on a vehicle:

• DO STORE TYRES so that they retain their shape.• Mounted tyres should preferable be infl ated to only 100 kPa (15 psi

/ 1 bar).• Be sure to adjust the tyres to the recommended infl ation pressure

PAX

SYSTEM

-

STORAGE


This is a used tyre which has had its tread replaced by a re-moulding process and has again been placed on the market for re-use. Despite the fact that these tyres have new parts, such as tyre treads, they are not new products but recycled products.

RETREADED TYRE

TYRE SEALANT KIT

For some years now, tyre sealant kits have been more commonplace in vehicles. One of its greatest advantages is the small space that it occupies, which allows greater boot space. The weight of the spare wheel is also saved, which means less fuel consumption by the vehicle.

These tyre sealant kits are sometimes optional, and sometimes they are mandatory; especially in cars with no space for a spare wheel, such as hy-brid vehicles in which the installation of batteries leaves hardly any space or LPG vehicles in which the gas tank is installed in the spare wheel area.

The kit consists of a tank with sealing foam and a compressor which is plugged into the vehicle’s 12V power socket. The seal-ing foam is only effective in the event of a puncture, it is of no use if the tyre sidewall splits and of even less use if the tyre bursts.

The tank with sealing foam is connected to the compressor, which is connected to the tyre valve with a pipe and fi tting at-tachment. When the compressor is operated, the sealing foam enters the tyre along with the air for fi lling the tyre. Once the op-erating pressure of the wheel is reached, wait for the time in-dicated by the manufacturer for the foam to seal the puncture.

One disadvantage of tyre sealant kits is that the sealing foam expires, normally every 4 years, and must be replaced. Similarly, once used, a new tank of sealing foam should be purchased. There are also aerosol kits which can be used directly without the need for an air compressor.


COMMON FAILURESTyres will have few faults during their useful life, but they are the vehicle’s point of contact with the road surface, therefore all actions and omissions in maintenance or driving practices will be refl ected in the tyre tread.

Their wear can be caused by braking, skidding, sudden acceleration, greater or lower pressure than what is required, unbalanced wheels and even worn steering and suspension due to improper use or neglect.

The most frequent cause of this kind of wear is the maladjustment of the front or rear axle geometry designed by the manufacturer.

Replace the tyres, align the steering and adjust the camber and caster of the relevant axle according to the manufacturer’s specifi cations.

One-sided wear

The tyre shows signs of wear on one of the sides of the tyre tread.

Central wear

The tyre shows signs of wear in the middle part of the tyre tread.

Depending on the tyre wear, check and correct the tyre pressures or replace the tyres.

The most frequent cause of this wear is excessive pressure in the tyres. Over-infl ation of the tyres may cause contact with the road to be mainly across the central part of the tread.

COMMON

FAILURES


Diagonal wear is almost always caused by lack of traction in the rear axles. Some vehicles are particularly susceptible to generating this type of wear. It is usually due to a very steep road with too much water run-off into the ditch which causes the vehicle to not grip horizontally, or the tolerance adjustments of the vehicle are excessive.

The most frequent cause of this wear is low infl ation pressure of the tyres. Driving with lower than the recommended pressure means that the tyre will be squashed against the road. Therefore there will be abnormal wear affect-ing both sides.

Depending on the tyre wear, check and correct the tyre pressures or replace the tyres.

Diagonal wear

The tyre shows signs of diagonal wear along the tyre tread. This wear is al-ways about 45° from the direction of travel. It may occur in one or several areas of the tyre.

Replace the tyres.

If the wheels are poorly balanced or the dampers are in poor condition, non-uniform wear may occur. In this case, an area of the tyre tread loses depth or prominence, while other areas remain in good condition. Heavy braking may also wear out the tyres irregularly.

Irregular wear

The tyre shows signs of irregular wear along the whole tyre tread.

Check the condition of the dampers and the wheel balancing. Replace the tyres depending on the degree of wear.

Wear on the outer edges

The tyre shows wear on the sides of the tyre tread.


COMMON

FAILURES

Deformations occur due to the poor condition of the rim or because the cover has been exposed to excessive heat or has suffered knocks, cuts, etc. The deformation can cause the tyre to burst.

Deformations

Deformations and dents appear on the tyre both in the tyre tread and in the sidewalls.

Check the condition of the rim and replace the tyres.

Cracks appear due to the ageing of tyre components, but there are factors which accelerate cracking such as exposure to major temperature changes, pollution, brake dust, infl ation pressures, etc.

Cracks

Cracks appear on the tyre sidewalls.

Replace the tyres

A tyre blow-out can be caused by over-temperatures due to driving at excessive speeds with a damaged or misshapen tyre, or without adequate tyre pressure. It can also be due to driving an overloaded vehicle which increases the recommended pressure for each tyre.

Blow-out

The tyre explodes, with the instant loss of all air pressure.

Check that the burst tyre has not damaged the rim or any components close to it. Replace the tyres.


a n eye o n au to m o t i ve te c h n o l o g yThe Eure!TechFlash newsletter is complementary to ADI’s training program Eure!Car and has a straightforward mission :

to provide up-to-date technical insight in innovations within the automotive environment.

With technical assistance of AD Technical Centre (Spain and Ireland) and assisted by the leading parts manufacturers, Eure!TechFlash aims to demystify new technologies and make them transparent, in order to stimulate professional repairers to keep pace with technology and to motivate them to continuously invest in technical education.

Eure!TechFlash will be issued 3 to 4 times a year.

a n eye o n au to m o t i ve te c h n o l o g yThe Eure!TechFlash newsletter is complementary to ADI’s training program Eure!Car and has a straightforward mission :

to provide up-to-date technical insight in innovations within the automotive environment.

The technical competence level of the mechanic is vital, and in the future may be decisive for the continued

existence of the professional repairer.

Eure!Car is an initiative by Autodistribution International, with

headquarters in Kortenberg, Belgium (www.ad-europe.com). The Eure!Car program contains a comprehensive series of high-profi le technical trainings for professional repairers, which are given by the national AD organizations and their parts distributors in 35 countries.

Visit www.eurecar.org for more information or to view the training courses.

industrial partners supporting Eure!Car

Disclaimer : the information featured in this guide is not exhaustive and is provided for information purposes only. Information does not incur the liability of the author.

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