Cross Drilled Rotors

Warped rotors are usually a sign of heavy braking, that, or a set of rotors that have been cut one too many times.............Perhaps a set of quality slotted rotors will help when coupled with a quality brake pad. However, if you do a lot of heavy late braking, your going to warp those as well.

Bill S.

Jamie Dezern wrote:

Oh, I don't know... I'm a crappy driver, myself, but the PowerSlots make up for a lot of foolishness.

dwight

Hey Dwight,

I've driven in your area, it is all late braking from light to light..........

Bill S.

dwight wrote:

The purpose of cross drilling is to allow better cooling. Warping is usually caused by overheating. Of course, like everything else, there's a trade off. Obviously, drilling holes reduces surface area. Reduced surface area will also decrease performance. Like putting on a smaller disc, something no one here would even consider! If overheating is a problem, your best bet is to install a 2-3" duct to direct fresh air into the center of the brake disc. Then you get better cooling and still maintain surface area. Also, a lot of folks like to install high performance racing type brake pads on their street car. They usually need to get fairly hot before they work well. That's a bad thing on a street car. If you don't have the correct discs, performance and longevity will suffer. Stick to a quality carbon fiber street pad. You'll get good braking for

Oh, and I forget to mention this. Cross drilling Lightens the rotor some, and we know what that does. It also creates stress risers. Eventually you'll develop cracking around the holes. When that happens you'll need to replace the discs. Cross drilling and slotting is really for race cars that really abuse their brakes - autocross, road course, short track. It should not be used for street and daily driver cars.

I was thinking about getting some Brembo cross drilled rotors. I do tend to brake pretty hard. Gas and brake are all I know say some, :) I'd just like to reduce the warping if possible after so many miles.

I don't recommend cross drilled rotor for anything other than looks, as you said they will crack. Slotted rotors for race only are fine but as posted earlier they will ware the pad faster than normal. This isn't a problem on a full blown race car but can become expensive on a daily ride.

Cross drilling and slots are intended to prevent gas produced by the binding material in the pad (the stuff that holds the pad material together) from building up between the pad and the rotor face. This pressurized gas acts like oil between the pad and the rotor preventing the pad material from directly contacting the surface of the rotor. Without contact there is no friction. Today's better made pads use binders which do not produce gas when heated, negating the need for cross drilling and slots on street cars. Racing being a whole other animal. Cross drilling does cause stress point in the rotor and have lead to cracking. Properly machined slots will not shave the surface of the pad causing shorter pad life. Todays crossdrilled /slotted rotors are mostly for show behind open rims. I run slotted rotors only because I find they don't fade as much on wet pavement (Water heated to steam can cause the same pressurized gas effect as cheap pads.) And down here in Louisiana we get a bit of rain.

Erich '86 GT - Unmarked