Thinking Cross-Drilled rotors?

[willwren]

The first thing we need to clarify is that there's cross-drilled (where the holes are drilled after machining) which are VERY bad, and will stress-crack and come apart. These are marketed for looks only, and the primary purchaser is a ricer/import tuner that doesn't know any better. Cuz cool brakes make the car FASTER, right?

The BETTER rotors have the holes cast into the blanks, then they're machined flat. These are stronger, but actually do NOTHING for you for several reasons, and even decrease braking power. They reduce the braking surface area, and modern pads don't have out-gassing problems. They also do little or nothing for brake cooling. They were never intended for street cars.

Slotted rotors are a good bet, but you have to keep the slots cleaned out for them to do any good. There are also some brands where the slot doesn't extend out to the edge of the rotor, essentially making the slots worthless for venting water and debris out.

Many brake shops will not turn drilled rotors due to liability. They will turn slotted.

[GonneVille]

Like Bill said, rotors with the cross-drill holes cast in, then machine finished are much safer than those where the hole are drilled into blank discs. When I had my 95 SSEi, I used crossdrilled rotors from PowerStop. I drove that car down roads that had caused the blank discs I got it with to fade to nothing before I was halfway through. The PowerStops, even with stock pads, stayed strong all the way through, and at higher speeds.


That said, I got similar results on the 98 PAU just by switching rotor and pad brands. My current set is Centric rotors and Satisfied Gran Sport pads, and the stopping power difference over the Brembo/Hawk setup is insane. The Centric rotors are nice too, because after almost four months, the paint they use on the unswept areas is still keeping the hub area from showing anything but a hint of rust.

[swampthing]

I always thought drilled rotors had more to do with rain and wet brakes, like the holes gave the water somewhere to go

[willwren]

The rain gets wiped away by the pad. You want to trap it in holes? That's what slots are for. Then again, it's not really that much of a benefit even with slots.

If you want to get technical, the holes give one more area to rust that never gets cleaned off by the pad. The rotors will start to micro-crack around each hole unless the stress-relieving and hardening is done LAST, and even then, these rotors are not intended for street use. If done properly, most of us wouldn't be able to afford them anyway. These are basic principles of metallurgy, not opinion.

[swampthing]

no argument here, my slotted cross drilled rotors are doing fine, I think mine are drilled blanks I'm really not sure. but I'm not hard on the car and I have no cracking/warp issues. the slotted rotors and ceramic pads feel much better on the pedal, and the car stops faster then it did with the stock pads and rotors.

I'm not arguing that crossdrilled is the way to go, if I had to do it over again I would probably just get slotted and get a better brand.

[renchjeep]

I'll probably get heck for digging up an old thread, but......
I warped 2 pairs of NAPA premium front rotors on my 94 SE (new NAPA premuim pads both times), even turned each set once they warped, and they both warped even more quickly. Against advice, and I have not read the "article", I bought a pair of drilled and slotted rotors from a seller on eBay for about $120.00. The company screwed up, and sent Centric ceramic pads as well! I installed the whole deal, and got better braking "feel", less brake fade, and no warping or noise issues. After 5,000 miles, still fine. The NAPA premium rotors had warped before this. I do know how to bed-in brakes, I think. I do brakes on Crown Vic Police Interceptors A LOT, and they have to be properly bedded in to avoid officer's brake compliants.
I drive quite hard on twisty mountain roads, and always value brakes and steering above all. If anything bad happens, I will let you all know. If I survive.
(Now that I have "bragged" about my brakes, the rotors will warp tomorrow! Or simply disintegrate, sending me over a cliff.)

p.s.--I have no problem with other NAPA parts, and use their parts almost exclusively on my other rides.

[repinS]

Warping brakes so soon? When was the last time you looked at your rear drum setup?

[willwren]

I agree. Your rear brakes need some attention, and you need to be properly torquing the front lugs in a staggered pattern, and with a drop of light oil on the threads each time.

Your braking improvement was mostly due to the ceramic pads.

[00Beast]

Dimpled/slotted rotors are be the best of both worlds, IMO.

[Grapes]

rotors warp.... i had a stiky caliper on my 97' f-150, when i dissasembled it, just out of curiosity we put it on a mill and measured the surface, it was warped, like wavy warped. i got it back to flat by running it on the mill, i just needed it to last a few more miles back then.

on my bonnie, i beleive the drilled rotors act like cheesegraters, and the slotted ones i have never tried. so i just use regular flat rotors and ceramic pads, not sure of brand because i have a guy that does them out of his garage, not a complaint to date though :D

[renchjeep]

Warping brakes so soon? When was the last time you looked at your rear drum setup?

Rears are good, replaced the hardware not long ago, check+adjust with each 3000 mile oil change.

[renchjeep]

I agree. Your rear brakes need some attention, and you need to be properly torquing the front lugs in a staggered pattern, and with a drop of light oil on the threads each time.

Your braking improvement was mostly due to the ceramic pads.

Maybe the pads are what did it. Rears are fine. Newer hardware (less than 1 year) and checked/adjusted every 3000 miles. I do lube the wheel studs with a drop of 30 wt., although I am guilty of using an impact to tighten the nuts (in the proper order), but have done this on all my cars and the Police fleet I service, over 100 vehicles, no issues with "excessive" warping. Usual hard cop use chews up brakes pretty quick, and some warp during/after high-speed pursuits.