(09-07-2018 )Hammerhead Wrote: There are many brands of clutches, but the design comes down to two basic types;
indirect, has angled springs that you are only pushing against part of. Requires more aggregate actual spring pressure because they also aren't pushing directly against the pressure plate. Most clutches are of this design, Eaton's Easypedal is the best at making a light pedal pressure than the rest, but there are knockoffs of them as well.
direct, as is obvious by the name, the springs push directly against the pressure plate. This means more leg force is required to release the clutch, but 100% of spring force is applied and they can produce more clamping force. The Lipe 1 is the most well known of this type.
The indirect is "smoother" to engage, because the springs are angled so only a portion of the pedal movement is directly acting on the springs/pressure plate, this is why they're easier to slip.
The direct is more aggressive on engagement, and if you're in a hurry or don't have the leg stamina to hold it when required, they can be more driveline abusive.
Every clutch linkage moves the release bearing a percentage of pedal movement. Think of it this way, if the linkage moves the release bearing at 0.10" for every inch of pedal movement then it's a 10:1 ratio and the angled springs further reduce that movement another 25%, then the pressure plate moves 0.075" for every inch of pedal movement on an Easypedal compared to the full 0.10" of pressure plate movement of the Lipe 1.
So it's harder to be smooth with a direct clutch, however they achieve more clamping force with less overall spring pressure. This means if you can be as gentle with a direct as you can with an indirect it should last longer. I've yet to see a Class 8 properly rated clutch wear out, the springs break or the damper plates crack and loose springs long before fiber ever wears out.
The best clutch would be a lock up, but nobody mass produces them. A lock up clutch uses direct springs with less spring pressure for smoother engagement, and has small arms with weights that apply force with centrifugal motion to "lock up" the clutch. For example, they would use 1500 ft/lbs of spring pressure, and 2000 ft/lbs of centrifugal pressure (or more) and this can be adjusted for aggression. They're higher maintenance and very expensive ($3k), but I do know someone that builds them.
I've used single, dual, and triple stage lockup clutches when I drag raced. If you can get them figured out, they're amazing. But it's not easy to properly harness their potential.
I have a feeling you are trying to tell me that it doesnt matter about rather the clutch wearing out but the springs, damper plates wear out or break on indirect or direct clutchs? So it all comes down personal preference? Correct me if i am wrong.
