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I just had new Rotors, Calipers and Pads installed on all 4 wheels of my 1985 Vette . It seems like the pads only cover about 1/2 the surface area of the rotor. This doesn't seem correct to me. I feel the pad should take advantage of all the exposed area of the rotor. How is this remedied? I have included a STOCK image... (this is not a photo of my wheel, but I see this setup has the same situation).
The mechanical advantage of disc brakes is having the pads as far to the outside of the rotor as possible. Yes you gain more pad area going lower, but the gains are minimal.
it's the way they are. If you notice how caliper is designed, the piston would not be centered on a pad that covers more rotor surface.
So you're saying, a different set of calipers would center on the pad differently and perhaps give better coverage. OK, I would think this has been covered before, has anyone ever suggested a caliper that positions the pad better?
The mechanical advantage of disc brakes is having the pads as far to the outside of the rotor as possible. Yes you gain more pad area going lower, but the gains are minimal.
I'm sorry, but I don't see the logic in that at all. If a pad grabs more area on the rotor, perhaps up to 50% more, how could the gains be minimal?
Most of todays disc brakes that I've witnessed, I see the entire surface of the rotor being used.
The entire surface of the rotor is being utilized... for better stopping results.
I've annotated the photo to show where I think the brake pads should be grabbing. On my 1985 c4 with new rotors, pads, and calipers, only half of that rotor area is being used.
I'm sorry, but I don't see the logic in that at all. If a pad grabs more area on the rotor, perhaps up to 50% more, how could the gains be minimal?
Most of todays disc brakes that I've witnessed, I see the entire surface of the rotor being used.
The entire surface of the rotor is being utilized... for better stopping results.
Think of it as trying to loosen a really tight bolt. Do you use a short handle ratchet or a long handle? You use the long handle because it requires less force on the end of the handle to apply the same amount of torque to the bolt. Same with the brakes. The axle is the bolt and the rotor is your handle length. Keeping the pad on the outside increases your mechanical advantage. The pad closer to the center will require more clamping force to achieve the same torque reduction as the pad on the outer part. I didn't say it wouldn't help at all, but the benefit is so low you are just wasting pad material at that point.
I no longer have a typical C4 setup, but yes pretty much anything from the late '80s to present will show less pad coverage radially, but will probably be longer. Having a longer pad that covers more area at the edge of the diameter is beneficial.
03-23-2017, 11:33 AM
Brake Pad Doesn't Cover Rotor Sufficiently
