Running low helix angles put enormous side pressure on a belt. If you run a 40 degree helix in the Tied clutch, it is like running a 23 degree helix in a non-tied design. (!) You would have to have HUGE gram weight in the drive clutch to get any upshift and the side pressure would make the belt bridge.
We did a lot of testing in the past to see if higher helix angles and stiffer springs were the way to go or lower helix angles and ligher springs were better.
What we found is that once you get below 36 degrees or so on the TSS-04 (non tied) clutch or 54 degrees on the Tied clutch, you get so much side pressure that the belt temperature starts to go up rather than down.
The other side of that coin is that if you go up on helix angle, you need more spring to make it backshift. This makes for a more sensitive setup.
Of course, this does not mean the Tied Clutch is more sensitive than the TSS-04 or TSS-98 clutches. The fact that the Tied clutch has both the stationary and moveable sheaves as torque sensing members means that the Tied clutch is "smarter" than clutches that only think with the moveable sheave. It needs more helix angle to transmit the same side pressure as the non-tied clutches. We find that even less spring pressure is needed to make the Tied clutch backshift. (am i confusing anyone yet?)
Your best bet is to give Jason a call on Wednesdays or Fridays at 218-846-6305 to talk about your specific application.
