Tuning Your Clutch

There are a couple of free modifications you can make to your clutch that will improve low-end acceleration. The first is to install the clutch shoes in leading edge engagement instead of a trailing edge engagement. The picture below shows the stock clutch configuration. This is called trailing edge engagement. What this means is that when the motor rotates counterclockwise, the trailing portion of the clutch shoe will swing out due to centrifugal force and contact the clutch bell. This is because, as the engine rotates, the pin that the clutch shoe pivots on is before the end of the clutch shoe that moves as RPM's increase.

In a leading edge engagement, the leading portion of the clutch will wing out and engage the clutch bell as the motor turns counterclockwise. Configuring the clutch in this manner slightly raises the RPM's at which the clutch will engage. This provides a snappier bottom end response. The downside is a small increase in clutch wear.

Another way to improve the response of your clutch is to trim the clutch shoes themselves. Before you do this I'd advise that you have a spare set of clutch shoes available, and to remove material in small increments. After all once you've removed a portion of the clutch shoe, there's no reversing what you've done.

What you are doing by cutting material off of the clutch shoe is making it lighter. A lighter clutch shoe will engage at a higher RPM. I would start by removing no more than 1/8 of an inch from the clutch shoe. Then run your truck to see what the effect of the modified clutch shoe is before removing any more material. Below is an example of a shortened clutch shoe, with a stock clutch shoe below it for comparison purposes.

Trimming the clutch shoes has the same result as trying different clutch springs. However different clutch springs can sometimes be difficult to find, and trimming the clutch shoe itself doesn't cost anything making it a more attractive alternative.

You should also keep in mind that the modifications shown above will increase low-end response from your nitro powered truck. However when running on loose surfaces they will also increase the tendency to spin the tires upon acceleration as well. Therefore these modifications should be used on high traction surfaces, or in conjunction with better tires.