Why such flat helixes

[lancelarue]

clutching

Helix diameter is a huge factor. Look at the old Polaris button helix vs a Team or A QRS or a Cat. All different diameters, so the angles (then throw in spring pressures) cannot be compared apples to apples as a bigger diameter helix/ roller position in relation to sheave diameter has more leverage.
And the new Doos run a straight 40 helix. 08 was a 42* then 09-11 was a 43/47 reverse angle, 12+ a straight 40 but also a much softer secondary spring.
The important thing is finding a "balance" in belt side force between the primary and secondary so they respond quickly and are not fighting one another, creating more heat than necessary.

Absolutely!!!!!!

I would concentrate on what the clutches want / need rather than what everyone thinks they need.

No matter what helix you run in the driven, if it doesn't hang on to the belt, not going to work right. Then the primary won't work right. They HAVE to work together.
My 2 cents:
In a mountain sled with big torque demands from big tracks, and more & more hp pulling on the belt, a lower helix angle with the "SOFTEST" spring it will run & still hang on to the belt will kick butt over a higher angle stiff spring scenario.
= awesome upshift with a wicked backshift every time. Cooler running belts.
Use the helix to provide the belt squeeze, NOT THE SPRING. Only fine tune with the spring, you'll be amazed.
When done with driven, fine tune drive to match. Here's where you can change your shift character to match engine power curve etc. and get the results you like. Ramps / weights / springs / rollers etc.
Only run just enough weight to provide just enough belt squeeze to match the driven. No more.
And hang on!!!!!!!!!!!

I've proven this out on everything up to monster turboed 4 strokes close to 300 hp. running 162" 3" tracks.
When I was done, still running the original stock Cat 85 gram weights that came in clutch oem 175hp, with little heat.!!!!!!!!