Typical pedal pressure for clutch (and how to measure it)

[ClutchFork]

With my painful left ankle I got to thinking to push on the bathroom scale to the point of pain I am feeling with my clutch pedal and get an idea of the pedal pressure. Tried it a couple time and getting around 80 pounds of pressure plus/minus about 20 pounds. Hard to tell because it is pretty artificial since I am not sitting and it is not a pedal, but the pain is there.

Anyway, what would be typical pressure for a clutch pedal? I am sure it varies in stock vehicles from say 40 to 120 pounds. Aftermarket clutches for high performance I could see going higher.

EDIT: Just tried it again with my foot angled differently and it seems closer to 40-60 pounds.

[Jastreb]

40-50 pounds sounds reasonable, they certainly wouldn't make it so that a small person (skinny 16 year old girl) wouldn't be able to use it.

Without buying specialized equipment, you could try hooking a small fishhook scale around the pedal and pulling down. You could also buy a compression spring and measure the deflection.

[theholycow]

A extension of the pedal using a 2x4 perpendicular to the pedal arm with the bathroom scale at the other end should provide a reasonably accurate measurement for our purposes. You'd have to push the scale with your hands.

Now I want to try it. My pedal's nicely heavy. Someone bump this thread in 8 or 9 hours, about 5:30pm eastern time, so I'll remember when I get home from work.

I originally was going to post a leverage trick straddling a short piece of 2x4 between the scale on the floor and the pedal but I realized that the pedal gets more of a forward pressure than downward (at least near the end of the stroke, in many cars) and so that measurement might not work well.

[ClutchFork]

A extension of the pedal using a 2x4 perpendicular to the pedal arm with the bathroom scale at the other end should provide a reasonably accurate measurement for our purposes. You'd have to push the scale with your hands.

I am going to try this on my truck and my son's S10 which he says has a much lighter clutch. But another factor: is it possible the pedal pressure is different engine off vs engine on and that may be so we should do it with the engine on.

No don't pull a Three Stooges and have the two by four slip, shoot out, and give you a black eye!

[theholycow]

Color me skeptical. I cannot imagine a way in which the engine running could have an effect on clutch pedal weight. Perhaps Rope-Pusher is reading this and can weigh in.

[ClutchFork]

Color me skeptical. I cannot imagine a way in which the engine running could have an effect on clutch pedal weight. Perhaps Rope-Pusher is reading this and can weigh in.

Perhaps when the shaft is spinning inside the throwout bearing it affects the resistance vs when it is static.

... effect on clutch pedal weight. Perhaps Rope-Pusher ... can weigh in.

"pedal weight" "weigh in" GOOD ONE Har har har!

[Rope-Pusher]

Clutch pedal force shouldn't increase with the engine runnin...Not unless you were talking about high rpms with a centerforce clutch.

I'd say passenger car clutch pedal force runs 20-40 lbs. Trucks and hypos stuff may run to the high end of that or even higher. This is why some manufacturers choose to go with dual-disc clutches - twiced the clamping for a given amount of pedal force. It's also why some go for very large clutch diameters, but that adds to shift inertia and shift loads go up. You can't wash something without getting something else dirty.

[ClutchFork]

Okay, I just measured my clutch pedal pressure, engine off, with a bathroom scale and a board about 40 inches long. I did it several times to get a good measurement, and it kept maxing out around 35 pounds.

Therefore the estimated clutch pedal force for my Ranger is 35 pounds.

[Squint]

Okay, I just measured my clutch pedal pressure, engine off, with a bathroom scale and a board about 40 inches long. I did it several times to get a good measurement, and it kept maxing out around 35 pounds.

Therefore the estimated clutch pedal force for my Ranger is 35 pounds.

Wait, so we're talking putting an extension on the clutch, then pushing a bathroom scale against it to see how much it takes to push in? Now I'm curious what the Fiesta's is...

[ClutchFork]

Wait, so we're talking putting an extension on the clutch, then pushing a bathroom scale against it to see how much it takes to push in? Now I'm curious what the Fiesta's is...

Yes, get a stick of wood long enough to put the bathroom scale beyond the steering wheel when pedal is depressed. Also be careful the stick does not slip off the scale and bash you in the face. My problem was the stick slipped off the clutch pedal a couple times. Also I checked the scale and the bottom was pretty solid, so the stick could push against it without a board across the scale bottom. Now the reading has to be +- 5 or so pounds considering the accuracy of the scale and the rigged test procedure, but close enough.

[theholycow]

Ok, I finally remembered to do mine. 60 pounds.

[ClutchFork]

Ok, I finally remembered to do mine. 60 pounds.

1980 car. Probably not hydraulically assisted clutch.

[theholycow]

1980 car. Probably not hydraulically assisted clutch.

Definitely hydraulic. I used the hydraulic system from a 1994 S10. It was much easier and cheaper than trying to rig up a rod linkage.

Throw at pedal and at both ends of fork seems about right. I suspect that the heavy weight is from the pressure plate/clutch cover assembly I used. It was a somewhat anonymous one lacking most documented specifications.
viewtopic.php?f=32&t=12612&p=306051&hil ... te#p306051
It's the second one in that post, CA1853. I think it's probably a very heavily sprung one, explaining both my pedal weight and the unmitigated success that I've had with my undersized clutch not slipping under load.

[Rope-Pusher]

viewtopic.php?f=32&t=12612&p=306051&hil ... te#p306051
It's the second one in that post, CA1853. I think it's probably a very heavily sprung one, explaining both my pedal weight and the unmitigated success that I've had with my undersized clutch not slipping under load.

It's not undersized. It's right-sized for the system.

[ClutchFork]

Definitely hydraulic. I used the hydraulic system from a 1994 S10. It was much easier and cheaper than trying to rig up a rod linkage.

Ah, I see. This is not a factory manual setup. You converted it. Nice work! More people should do this. The fact that it is working is a major success as I understand this is not a simple task.

I recall my '77 F150 had full manual linkage and it was giving me pain in my knee after 7 years of driving it. Would love to know what the pedal pressure was on that.