Stm secondary

[nelsonhouse]

Hi everyone,
I’ve just ordered an STM secondary clutch for my 2019 Alpha One, and I’m looking for some input from those who’ve run a similar setup. I went with the KSS8 lime green spring and a 44/36 helix. My goal is to improve performance, especially in terms of backshifting and consistent power delivery in deep snow conditions.

Has anyone here tried an STM secondary on the Alpha One, or a similar sled
• How does it perform compared to the stock secondary?
• Any tips for fine-tuning this combo?
• Are there specific adjustments or setups I should be mindful of to maximize performance?

I’d love to hear your experiences—whether it’s clutch performance, durability, or just general impressions. Also, if you’ve run a different spring or helix combo on the STM, I’d be curious about how that worked for you.

Thanks in advance for the advice

 

[spoon]

I ran an STM secondary on an M1000 turbo as it was the only option other than stock for the diamond drive. Reverse not working ideally was the only issue I experienced at that time. I see the design has changed for the newer sleds and reverse should be good especially since you are running the compression spring. I liked the fact that you had a bigger choice for belts to play with for top speeds or low end gains depending if you went longer or shorter.

 

[nelsonhouse]

I ran an STM secondary on an M1000 turbo as it was the only option other than stock for the diamond drive. Reverse not working ideally was the only issue I experienced at that time. I see the design has changed for the newer sleds and reverse should be good especially since you are running the compression spring. I liked the fact that you had a bigger choice for belts to play with for top speeds or low end gains depending if you went longer or shorter.

How was the durability of the Stm secondary on your M1000 turbo?
What kind of spring and helix did you run on your M1000?

 

[spoon]

How was the durability of the Stm secondary on your M1000 turbo?
What kind of spring and helix did you run on your M1000?

Rollers were an issue then, looks like new design now and the springs and helix were all ones I had as the first gen STM were just a billet copy of the old Arctic Cat reverse helix design from the 70s that is still in use today on some applications for racing. Second Gen design is aimed at the engine reverse crowd.