Why are Pressure Plates so Heavy?

[echrisconnor]

I just got a new pressure plate since I intend to replace my clutch while the engine out. I picked the thing up and looked if over. Man, is this thing heavy-duty. I realize that this thing provides clamping to deliver the power to the car, but everything looks really hefty. There are aluminum versions available which cut weight down, but it seems that if lightness were an objective, there would be a considerable amount of material here to knock off.


Why do they need to be so heavy? Does the extra weight help it idle smoothly?

[Zeke]

Not necessarily. The mass deals with the heat so as to remain true. The alum coupled with a 4 puck disc might save enough weight to notice.

And, you can lighten your flywheel. By then, with the other two, you'd notice characteristics not just at idle, but starting off as well.

[dtw]

Inertia. Helps keep your motor spinning, such as between shifts, so you don't have to modulate engine speed constantly with your foot. Convenient for street driving but dulls throttle response significantly, which is why racers get light ones.