Bridgestone Unveils New Rubber for Road and Dirt
The historic city of Cologne was the venue Bridgestone decided upon for the official release of the two newest additions to its two-wheel range. And these two tyres highlight just how diversified the motorcycle tyre sector has become.
The more significant of the new releases for Bridgestone is the BT-021 sport touring tyre. Slated as the eventual replacement for the six-year old BT-020, the company’s best selling sports touring tyre, the new tyre is – in the opinion of its manufacturer – superior to the BT-020 in every major criteria.
The BT-021 is the first Bridgestone product line to employ what the company calls MSB (Mono Spiral Belt), a carcass manufacturing technique that provides greater flexibility than other types of steel belting, on both front and rear tyres. In addition to its reported heat dissipation effectiveness, Bridgestone reports that the MSB design also provides substantial shock absorption characteristics and a high level of stability even when confronted with demanding motorway conditions and hairpin curves.
The front and rear tread sports a new ‘slash pattern’ design and the front tyre has been given additional wide grooves stretching across the entire tread pattern, a feature intended to enhance handling and steering precision. The rear tyre, as expected, employs Bridgestone’s SACT (Straight and Cornering Technology) tread construction and dual compound tread, providing the combination of soft and hard tread necessary for a successful hard wearing performance tyre.
Bridgestone claims the new tyre will provide 15 per cent higher mileage than the BT-020, with tests showing a greater resistance to irregular wear. The rear tyre’s tread has a low negative ratio in the centre, meaning more rubber is touching the road – always a good thing in terms of durability. Bridgestone also points out that the low negative ratio cuts down the amount of pattern noise generated by air bumping.
The Battlax BT-021 is designed with heavier sport touring motorcycles in mind and is most suitable for bikes between 600 and 1200cc. The full BT-021 range includes 5 front-wheel sizes and 7 rear-wheel sizes, and will gradually supersede the older BT-020.
Also new at Intermot is a completely different kind of motorcycle tyre – M403/M404 combination designed for the motocross market. Intended for medium terrain use, the new M403/M404 line-up features 6 front-wheel and 10 rear-wheel sizes, fitting motocross bikes ranging in dimensions from diminutive 50cc models right up to the heftier 450cc offerings.
When Bridgestone tested the new tyres against the existing M401/M402 combination they reported a noticeably better contact feel and controllability in corners, right up to full lean. Traction and slide control coming out of corners is apparently also superior to that provided by the older tyres, enabling more power to be unleashed during acceleration.
Prototypes tyres were developed and tested by top Motocross Grand Prix riders and teams, including the new 2006 FIM MX2 world champion, Christophe Pourcel, and the winning Bridgestone-sponsored GPKR team. The M403/M404 will progressively replace the existing M401/M402 range across Europe from early 2007.