New shock absorber to debut at Catalunya.

Toulouse based suspension specialists Bos-Engineering will make their official 250 GP debut at Catalunya this weekend when the Equipe Grand Prix de France team will run the company's new SBR5 shock absorber - developed in record time since the project started from scratch in March.

This firm, founded in 1999 by Olivier Bossard, has quickly built an impressive record of off-road competition success, having manufactured the Rally Raid factory shocks for the Mitsubishi Pajero (winner of the 05 Dakar), the shocks for the official Citro?n C2, currently leading the Junior WRC World Championship, while also setting-up the suspension for Team Yamaha Enduro riders Marc Germain and David Fr?tign?.

But the technicians at Bos-Engineering were convinced that their shock design was also worth developing for motorcycle road racing and soon began discussions with Team Grand Prix de France for a technical partnership.

Team principal Jean Claude Besse was keen to bring a new French shock into GP racing and terms of agreement were soon reached: Bos was to produce a prototype which Sylvain Guintoli would test over the winter, without pressure or expectation.

Indeed, Bos were realistic about the size of the task ahead and had no illusions of revolutionising motorcycle suspension or magically gaining two-seconds per lap. The plan was simply to test and accumulate information before making a decision on the project's future.

If the prototype shock performed well - meaning that it provided a significant improvement in handling - it was foreseen that it might be used in racing this year. If the design was not of significant benefit, or simply not suited to road racing, it would be back to the drawing board with the aim of redesigning the shock for the 2006 season.

A prototype was thus produced and ran for the first time in private tests at Valencia - and Guintoli promptly declared that he was very satisfied with the effect that the shock had on the handling of his machine. Those results were then confirmed two-weeks later in the IRTA pre-season tests at Barcelona and, as a result, the team asked to use the new shock during the 2005 season.

But up to and including last weekend's Italian GP, Team GP de France had only that one prototype shock for Guintoli to use. In the meantime the final version, named the SBR5 (pictured), was being drawn up and four of these new shocks will be delivered to the team in Barcelona this weekend.

The SBR5 is a 'bitube' hydraulic shock. The compression and extension circuits are totally independent. Adjustments made to one circuit thus interfere in no way with the other. Furthermore, a third circuit allows both circuits to be adjusted simultaneously, to maintain the same ratio compression/rebound, in case of wet conditions for example.

In terms of adjustments, the shock claims to offer finer tuning possibilities than traditional models, and offer significantly greater amplitude. The SBR5 is also around 700g lighter than most existing units, with the overall weight of the shock - including its titanium spring - just 1500g.

In terms of handling, weight transfer is said to be better controlled, more progressive, while - according to Guintoli - the motorcycle feels more comfortable and less tiring to ride. It is also expected that tyre wear rates will be improved.

Guintoli and Gr?gory Leblanc will have two SBR5s units each this weekend at Catalunya, marking Bos-Engineering's official entry into Motorcycle Grand Prix racing.

Though it is still early to predict the future of Bos-Engineering in road racing, the company have been sufficiently encouraged to consider the commercialisation of a SBR6 for next season.

With the experience gained this season, Bos-Engineering could offer the SBR6 to teams competing in 125 and 250 GP - and are considering modifying the unit for 600 Supersport or Superbike racing.