Now with over 60 different clutches, The sigma range incorporates many popular street bikes as well as the race applications that have made there name. Sigma slipper clutches are designed to allow easier downshifting on the road or track. Originally a pure race accessory our slipper clutches smooth gear changes for skilled riders and beginners alike by automatically and seamlessly disengaging the clutch whenever engine braking or rear wheel hop becomes excessive. In racing SIGMA slipper clutches have proven themselves to be a reliable and effective addition to many a racing teams armoury. On their very first outing in a Ducati back in 1998 they won a World Superbike support race at Donington and in 2004 at Brands Hatch won their very first British Supersport race on Jay Vincent's Padgett's CBR 600. Since then they have won many BSB Supersport races and championships and a bunch of TT’s and North West 200 races.
Riders report smoother performance on corner entry and exit, crisper shifting action and increased ‘zip’ from the motor as major improvements over the OEM slipper units. All clutches are supplied with alternative spring preload spacers to allow slip levels to be adjusted. Each clutch is individually designed using carefully chosen ramp angles with ball bearings for the smoothest performance possible on road or track. All are supplied with full instructions. Most models use standard springs and plates.