SMC Bullet Clutches

Racers that prefer a "hard hitting" clutch will find something new in the SMC Bullet clutches: solid engagement without chatter or excessive engine bogging. 

SMC spring dimensions are very different from those used in every other clutch.  They are  engineered specifically for kart racing in order to eliminate air gap sensitivity. 

The springs used in every other disc clutch are off-the-shelf or general purpose items.  A common half-inch diameter, half-inch long spiral of wire that happens to work well if the clutch discs are limited to a very tiny range of axial movement or air gap.  Inexpensive.  No thought required.  The problem is that spring tolerances and minor adjustment errors easily use up the limited air gap.  Every time the kart goes on the race track the clutch discs wear a bit and the air gap grows.  Before long the clutch begins to chatter and acceleration suffers.  The engine will feel chatter long before the racer can feel it, consequently repairs are initiated a couple of races too late.  Perhaps the biggest problem with air gap is that it is very difficult to reset.  Most racers send the clutch back to its maker, sit out a race or two then pay a big repair bill.

SMC springs and levers were designed together as a matched set.  They work perfectly at any reasonable air gap and the racer can focus on more important matters.  Repairs are far less frequent and since the air gap is not an issue, the racer can do it himself in a few minutes for only the cost of parts.

Engine Applications:

One disc, two discs or three?