Clutch Math

9724VF350

9724VF350

Tractor Guy
Joined
Mar 2, 2010
Messages
2,784
Clutch #1

13" double, 2050 lb.

Clutch #2

11" triple, 2400 lb.

All other things being equal, which one has more holding power and how do you figure that up?

If I poke some numbers into the calculator based on square inches and #, It says the 11" may be about 23% more clutch, but I think it's more complicated than that and diameter makes a big difference real quick.
 
Clutch #1: A=(Pi)xR^2=132.66 sqin (x 4sides)=530.66 sqin total

Clutch #2: A=(Pi)xR^2=94.99 sqin (x 6sides)=569.91 sqin total

Assuming the co-efficient of friction is more with the higher clamping pressure plate (same materials) the triple easily has more holding power. The big equalizing factor here is increased surface area of a triple versus a double with a bigger diameter.
 
That's essentially how I did it, But I'm under the impression that the "more leverage" of the 13" gave it more of a advantage than can be calculated by figuring up square inches.

One thing I did differently, I subtracted the lack of square inches of contact due to the friction surface only being ~2" wide on both discs.
 
Last edited:
9724VF350 said:
That's essentially how I did it, But I'm under the impression that the "more leverage" of the 13" gave it more of a advantage than can be calculated by figuring up square inches.

One thing I did differently, I subtracted the lack of square inches of contact due to the friction surface only being ~2" wide on both discs.
Click to expand...

The lack of material in the middle will proportionally create less holding power of the 11 than the 13 but I think it's negligible in this case. I'm not sure what you are referring to in regards to leverage but total surface area and co-efficient of friction are the two most important factors. Surface area is critically important. Try taking two phone books and interleafing the pages and let me know if you can pull them apart. :)
 
Take for instance 2 clutches, one being 13 and one being 11. Both have 6 buttons on each side of the disc. All buttons are ~2 square inches. You actually have the same square inches of actual contact surface, but the 13" disc reaches out 7.5" from center whereas the 11 only reaches out 5.5" That's what I'm referring to as leverage.

I can see where that can still fall under square inches, but...............

I've argued with myself on this subject for quite a while before I brought it here.
 
I would still think the pressure plate and distribution of force would be proportional to each size diameter clutch.
 
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