Dirt Trail and Rally tyre performance is crucial

Dirt trial, like gymkhana, is a timed competition with one car at a time racing against the clock on unpaved roads. It is another hugely popular sport as, unlike in rallying, the course is laid out so that spectators can see the cars for most of the race.

The conditions on a dirt trial course constantly change with surface conditions affected not just by the weather, but by each run over the course. This makes tyre selection and driver technique critical as competitors seek ways of shaving thousandths of a second off times.

Rallying is more of a participation sport - especially in Europe - but still attracts thousands of spectators. The pinnacle of rallying is WRC which has moved away from its traditional European heartland in recent years with Japan joining the calendar in 2004 and 2005 with great success.

Rally and Dirt trial require best tyre performance

Tyre performance and tyre selection are crucial in both dirt trial and rallying leading to ferocious competition among tyre manufacturers to deliver the best tyre performance. The race results the tyres deliver have a direct effect on sales but Bridgestone has prevailed to achieve the best results and secure top market share in Japan.

Competitors in dirt trial have been clamouring for tyres that provide better grip and traction on the fields that offer a harder-packed surface every year. In rallying, a single tyre pattern must be employed for several of the timed Special Stages on diverse road conditions so a tyre with excellent grip in the broadest possible range of conditions is required.

RE460R introduced to deal with a wide range of surfaces

Bridgestone introduced the RE460R in 1999 as it fused the tread patterns of two predecessors - the RE360R for paved to hard dirt surfaces and the RE380R for hard to soft dirt - creating a single tyre that could deal with a wide range of surfaces. The RE460R improved performance on hard dirt surfaces for dirt trial courses, and improved all-round performance on everything from paved roads to ordinary dirt roads for rallying.

Three specifications were also available for fine-tuning performance. TYPE R was suitable for dirt trial hard dirt and the all-round demands of rallying. TYPE S was for hard-to-regular dirt in dirt trial and regular-to-soft dirt in rally. TYPE H was designed for long-distance rallying and practice runs with enhanced wear resistance and performance-endurance characteristics.

The RE460R proved hugely successful claiming three consecutive titles in the dirt trial A2 class and monopolising the top finishes in other classes.

RE470R offers improved grip levels

In 2003 Bridgestone introduced the RE470R to improve on the level of grip achieved on hard dirt surfaces by the RE460R. It incorporated an asymmetric directional tread pattern and a new soft compound with particulate carbon. The performance of the RE470R left its rivals in the dust. It was rolled out to seven classes of the 2003 All Japan Dirt Trial Championship and won championships in five classes. Drivers praised them for their exceptional traction and they have become by far the most commonly used tyres in dirt trials. Because of their popularity production has struggled to keep up with demand - at the competitions themselves the customers just keep coming.

For the 2006 season, Bridgestone launched two new specs of tyres, the POTENZA RE480R for use on loose gravel, and the POTENZA RE461R Kai for use on tarmac. As a result, Bridgestone-shod drivers claimed titles in one of the three All Japan Rally Championship classes and in four of the nine All Japan Dirt Trial Championship classes.