Now with over 40 different clutches, our range incorporates many popular street bikes as well as the race applications that have made our 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.

This section of the website is dedicated to slipper clutches, how they work, how to adjust them, where they came from, why ours are the best and how to order one for your own engine.

Five ramp, wet type.åÊ Hard anodised in grey. Clutch centre only. Uses standard clutch plates and spring.

Essential for racers, trackday goers and road riders alike...

• Avoids locking your rear wheel up or "hopping" when down-changing rapidly for greatly increased control and safety
• Helps to protect your engine and its valves in the event of an accidental/inadvertent downshift
• Employs the latest bearings & ramp technology for unnoticed, seamless, operation
• Automatically adjusts slip to your riding style for the smoothest corner entry
• As easy to install/change as your bike's original clutch
• Uses standard clutch plates and springs (not supplied)