Going down the green tyre route

Feature

There was a time when tyre manufacturers found it difficult to produce ‘greener’ tyres without compromising in other areas. But this is no longer the case, according to industry association Tyresafe

Having been set emission performance standards by the European Commission which aim to reduce average vehicle CO2 emissions to 130g/km by 2012, vehicle and tyre manufacturers have been working together closely to develop new technologies that will help achieve these targets. In some cases, not only is the emissions performance improved, but perhaps equally importantly, driver safety is also enhanced, making another vital contribution to society.

Run-flat tyres
Run-flat tyres are not a particularly new concept, however, in recent years a growing number of vehicle manufacturers have fitted these as standard. Run-flats have been developed primarily from a safety perspective, allowing drivers to continue their journey, albeit at a limited speed and distance, when the tyre loses air pressure.

The benefits of fitting run-flats can be considerable. Drivers are less likely to suffer from a dangerous blowout at high speeds; they remove the need to make dangerous wheel changes at the side of a busy motorway; and they stop drivers being stranded in remote locations. However, from an environmental perspective, run-flats can also encourage behaviour that helps to reduce emissions.

Tyre pressure monitoring systems
Cars fitted with run-flat tyres must be equipped with a Tyre Pressure Monitoring Systems (TPMS) system. These complex devices utilise sensors which alert the driver if a tyre loses pressure. The system is required because the sidewalls of run-flat tyres are much stiffer than their standard equivalents, meaning that drivers may not be able to tell that they have a puncture or under-inflated tyre without any electronic intervention.

Consequently, cars fitted with run-flats systems, or indeed stand alone TPMS systems, are much more likely to have their tyres at the correct operating pressures as the driver will have been alerted to a reduction in pressure. This is an important factor in helping vehicles achieve their emissions targets. When tyres are correctly inflated their contact patch with the road surface is optimised. This means that not only are they in their safest state, giving the best levels of grip and braking performance, but they also have their lowest rolling resistance and deliver the best fuel economy.

One leading tyre manufacturer and founding member of TyreSafe calculated that when a car’s tyres are under-inflated by just 10psi, fuel consumption, and therefore emissions, can increase by as much as three percent. The cost for fleets however, doesn’t end there as tyre life is also dramatically reduced by under-inflation. A tyre under-inflated by 20 per cent will also see a reduction in its life by 20 per cent. Tyres which run under-inflated are also much more likely to suffer from a dangerous blowout, endangering both the driver and other road users.

Eco-tyres
Another technology becoming more widespread in the quest for reduced emissions is the use of ‘eco-tyres’ or fuel efficient tyres. This type of tyre is designed to have lower levels of rolling resistance which means that less power is need to move the tyre along the road surface, and consequently the vehicle uses less fuel.

Tyre design is always a compromise and historically tyre manufacturers have found it difficult to improve the fuel consumption performance without significantly reducing the grip or tyre life characteristics. However, by finding ways to replace the carbon black in the tread compound with silica, tyre manufacturers are now able to produce tyres which have both lower rolling resistance and improved wet grip.

Maintenance
Despite the many technological advances made by both vehicle and tyre manufacturers, drivers and fleet managers continue to play a critical role in the contribution of tyres towards emissions reduction. Regular checks and maintenance are essential to ensure optimum performance, but also to maintain high levels of safety. By following TyreSafe’s advice, drivers and fleet managers can help to further reduce emissions.

  • Tyre pressures should be checked at least once a month and before a long journey.
  • Pressure should be checked against the vehicle manufacturer’s recommended level. This can be found in the vehicle handbook and on a plate by the driver’s door sill or inside the fuel filler cap.
  • If you are carrying extra passengers or a full load, pressures should be adjusted in line with the vehicle manufacturer’s recommendations.
  • Pressures should be checked when the tyres are cold (i.e. when you have travelled less than two miles).
  • Use an accurate and reliable pressure gauge
  • Check the pressure in all four tyres and don’t forget to check the spare.
  • When checking pressures give the rest of the tyre a visual inspection. Remove and stones and other objects embedded in the tread. If the tyre has any lumps, bulges or cuts it should be inspected immediately by a professional. Look for any signs of irregular wear on the tread.
  • If in any doubt about your tyre pressure or condition, take your vehicle to your nearest approved fitting centre.

TyreSafe is the new name for the Tyre Industry Council, a not for profit non commercial organisation set up 16 years ago with the responsibility of raising the awareness of the importance of the dangers of defective and worn tyres.

For more information
www.tyresafe.org