My best setup so far has been:
Rage 6 Gen 2 Primary: Red Spring, 6 grams at the base of the main arms (three washers each side) Centre and tip of main arms empty, small arms 4 grams on each arm (two washers each side). Engagement RPM is around 1950, back shifting is excellent
Gen 2 Secondary: Lime Green Spring, 50/40 Helix
- I have been trying to avoid using the Tungsten washers where possible as they have been susceptible to flying off, (1) Tungsten weight = 7 grams, (1) Steel Washer weight = 1 Gram
- The lime green secondary spring has a stiffer initial rate than the gold secondary spring and a lighter finish rate. This keeps you in a lower gear ratio at first to make take offs in soft ground (sand) or up hills a bit easier and the lighter finish rate give you more top end, just keep an eye on your belt temp because there could be potential for belt slippage and heat at high loads/speeds for long duration with the lighter finish rate.
- The only thing that my setup is still lacking is good belt grab at lower speeds and less than half throttle. A straight 40 Helix or Straight 45 or even a 35/45 might improve that slightly but the main underlying problem is that the STM super tip cam arms have too flat of a profile to let the weight do the work that is needed in an ATV/UTV application at lower RPM's and speeds, especially in high load situations like loose sand or when running big tires.
The good news is that STM has some new Cam arms in development that are specifically designed for ATV/UTV use, and I am told that they will be released in the next few weeks. If done correctly these new profile arms should make a huge difference on the belt hookup at less than full throttle.
I am currently testing a Second generation Primary from QSC based off of a not yet released primary from Team. I will not say too much about it yet because it is still testing and needing some changes. I will tell you that the Cam Arms are designed in a way that allows the weight to do work down low a LOT better than the current STM arms, and the difference between the two primaries in low speed drivability without belt slippage is NIGHT AND DAY. It is like driving a whole new machine and is a complete pleasure to drive compared to my best setup on the Rage 6.
I feel that the redesigned, soon to be released, cam arms for the STM Rage Primary should make a big difference on the because the profiles they are using now were not originally designed for ATV/UTV use in mind and that is the biggest problem right now.
