I have new Powerslot rotors and Hawk HPS pads on the front and rear now. I noticed on the rear that the pad doesn't cover the entire surface of rotor like the front does, has anyone ever noticed this? It would be nice if they used a caliper and pad big enough to use the entire surface of the rotor that is available. You can see what im talking about in the photos.

Front you can see where the caliper clamps down right up to the hub of the rotor


Rear you can see there is a spot where there is no contact

 

I noticed the same thing after changing to Hawk pads, my best guess is Hawk made the rear pads smaller due to the fact that their pads are supposed to bite harder than OEM pads and they did not want to disrupt the brake bias of the car.

 

it's not hawk's fualt, it's the design of the caliper. majority of your stopping power comes from the front anyways

 

yah my stocks are like that. The inside part doesn't get touched

 

Yeah I guess its only grabbing what the engineers wanted it to grab but would be nice if it clamped down on the whole surface area. Then just make the fronts bigger to even it out! I wonder if thats what they did on the new SS/TC's brakes.

It reminds me of if your hand was a caliper, just pinching the edge of a rotor instead of grabbing it with your whole hand to stop it from spinning.

 

The force of the pad on the rotor * the coefficient of friction = stopping power. The force is determined by the caliper and the hawk pads have a higher coefficient of friction than the OEM pads. That means you have more stopping power regardless of how "big" the pads are.

Basically the only thing that you'd gain from making the pads "bigger" would be longer pad life, but they already outlast the fronts and most people replace them at the same time. Making them bigger would make them more expensive, and you'd still probably replace then when you replaced the fronts.

 

Well there isn't any difference in size between the Hawk and the stock pads. Its just that I never paid attention to it until after I put the new pads/rotors on and was admiring my work. (This is all just an excuse to show off my new rotors by the way!)

I can see what you are saying, the same amount of force is being applied to the caliper whether you have a huge pad or a small one. Its just that I would rather have a 5 inch pad that evenly covers the entire surface of the rotor than a tiny one that only grabs the edge whether it be for reasons of stopping power or pad life. My thinking is that there is an issue of traction, just like with tires, and a smaller friction area has less hiolding power than a larger one under force.

 

The area makes a VERY small difference in stopping power. If you were way outside of the design range of the friction material (something stupid like a 1" square pad or something) then you'd lose stopping power obviously, but making the hawk pads a little bigger wouldn't change anything as far as that goes.

Tires are different in that rubber can stretch and the "lugs" deflect under force. The pad is totally solid for all practical purposes.

Yes, Hawk could have made the pads a little bigger and you'd end up with longer pad life and more even rotor wear, but they'd have to jack up the price and risk them being too big to fit some aftermarket rotors.

They do look pretty good by the way... hopefully the brake dust isn't too huge of a problem on those polished wheels.

 

No the hawk pads are fine they are only doing what the OEM has specified for the car. I think it was probably a 2 cents per car cost savings measure or something on the part of GM. I do however think there would be a difference if that entire surface was in contact with a pad. I think that a larger friction area can apply more stopping power than a smaller friction area. I think there is enough power in the braking system to benefit from this increased contact area.

Thanks by the way, and they actually have much less dust than the cheap pads beleive it or not.

 

Impressive about the dust thing. I'll probably go with the Hawk pads over the EBC ones when I need them then I suppose.

I'm really not trying to argue about the pad size, just offering a little info. I'm an engineer by trade and while I don't have actual specs on these brakes in front of me, we don't generally make things worse when it's THAT easy to make them better.

 

Well at least you're a nice guy! I had a feeling you were an engineer. My suspicion is that your right its probably not that huge of a difference in braking performance, so they could get away with using the smaller calipers and pads and save a few cents.

 

Now changing the calipers would be a totally different story. If you increased the caliper size (go to a caliper with a larger piston or multiple pistons) you can greatly increase the clamping force, which would have a large effect on braking. For street use however, I'm thinking having good stock size pads and rotors will be just as good, the main reasons people go to big brake kits are for the added cooling capacity, or just to look cool

Personally I think I'll go with the EBC slotted and dimpled rotors along with Hawk HPS pads, or maybe the EBC green pads. The green pads are supposed to be quieter, but I believe they are dustier than the stock ones.

 

Mine are definitely better than stock, they haven't been bled but haven't needed to because never opened up the hydraulic lines. I have heard people say that drilled and slotted rotors have less surface area so initial braking performance is hurt by using them. I have to say they do feel just a touch less grabby then they were stock, when they were new. I would like to bleed them first to be sure there isn't any air in the lines before i could say for sure. But where they shine is in the rain, in hard stops, and in heavy traffic there is no fade and no comparison to the stock parts. .

Mine are absoultely slient, maybe the faintest scraping noise, and there has been no brake dust at all after a few weeks since i polished those wheels.

 

Even the stock brakes are pretty good (at least on the SS/SC). They're on par with what BMW is selling these days... you can't really go wrong with any quality pad on these cars. I'd avoid the $30 pads from the counter at the parts store, but anything from Hawk, EBC, other quality manufacturers, and even the OEM pads are good. I believe GM even has ceramic pads available as well.

 

The OE pads grab fine, but the dust is totally unacceptable......it's brutal! I finally got fed up and bought some Powerslot rotors and Hawk Peformance Ceramic pads, which just arrived today......can't wait to put them on!

 

thats great, I have had mine on for a while now still not a speck of brake dust.