Cold Tested: Thunder Products Go-Rings

At first, I was a skeptic. I’ve spent a lot of time around clutches and when I was told of a $19.95 solution to prevent a hard primary clutch engagement by replacing stock O-rings with O-rings with a flat side, I was not drinking the Kool-Aid. In my experience, a clutch that engaged hard usually required shimming the sheaves to provide proper belt-to-sheave clearance. This requires a lot of work and special tools to do it yourself, or a visit to a shop.

Our test sled was a 2013 Arctic Cat M8 153. Its owner had complained about a hard clutch engagement and was looking for a solution. He bought the sled used and assumed it needed some adjusting to the clutch, but was considering buying a new TEAM clutch, which is a relatively expensive solution. I told him that I thought the stock clutches would be fine if properly shimmed, but first I thought the sled might be a good test unit for the Thunder Products Arctic Cat Drive Clutch Go-Rings.

With a doubting heart and a bad attitude, I installed the Go-Rings. The installation only took as much time as it takes to switch weights in a clutch (approximately 10 minutes). The instructions were good, but not necessary if you have ever changed weights in a clutch – the Go-Rings simply replace the rounded factory O-rings, with the flat side of the Go-Rings going to the outside of the weight. The factory weights had an indentation where the factory O-rings seated against them.

Click to enlarge.

We had tested the sled prior to installation on several different surfaces to ensure a solid baseline to measure from and compare to. We were surprised when the results were amazing the engagement was much smoother. I have added/replaced shims to adjust the belt-to-sheave distance many times over the past 35 years and the final result seemed to be the same. What is actually taking place is the stock O-rings have a significant amount of drag on the system. This gives the appearance of a wide belt-to-sheave distance, but in reality it is not the case.

A clutch that slams into engagement is not only annoying, but it adds to the wear-and-tear on the drivetrain, decreasing belt life and in many cases reducing take-off performance. On mountain sleds it makes creeping out of a hole in a stuck situation more difficult. The reduced drag from the Go-Rings offered a faster clutch back shift for increased performance.

Overall, I went from skeptic to believer, and I give this product an “A.”

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