Thunder Shift
Superior Performance Through Superior Clutching

All NEW: Thunder Shift Arms
Thunder Shift Rollers

WEIGHT SPECIFIC CLUTCHING

Whether you have been around snowmobiling many years or just a few, you have probably realized that the most "bang for the buck" in terms of performance comes from proper clutching. We want to introduce you to a new term called Weight Specific Clutching. In a nutshell, this means a specific rider and sled combination require a specific amount of weight in a clutch.

Lets say we have a 500 pound sled with a 100 HP engine. If the rider's weight is 200 pounds, that is a total of 700 pounds or 1 HP for every 7 pounds of weight. now lets say we have the same sled with a 130 pound rider on board. That is a 70 pound weight advantage or the equivalent of a 10 HP advantage. What we are getting at is that weight equals horse power. Even a 7 pound difference in rider weight is the equivalent of a 1 HP advantage. Every change in HP requires different clutching. Nobody argues this!

Very little consideration or effort is given to clutching a sled differently because of a 20, 30, 40, or even 50 pound weight difference, although it is the same as a HP difference. The reason this is not talked about or given much consideration is because this has been a difficult task, often involving different weights, primary springs, secondary springs, helix, or even worse, having to grind the clutch weights or ramps by hand in a hit or miss fashion. Now you can easily practice weight specific clutching and get that fine performance edge usually reserved for factory riders. The Thunder Shift clutch kit was designed with WSC in mind.

The bottom line is this: if you throw all the weight at your engine that is possible without the RPM's dropping below the desired RPM and your sled holds this all the way to top speed that is the fastest that your sled can possibly run regardless of who clutches it. That is WSC!!