Only posers
Rookie
Joined: May 2011
Posts: 79
Likes: 0
From: CA
They're there for a reason. Slotted will perform better. But wear much quicker. Also be less effective when wet. Flat doesn't have the heat dissipation needed for a performance application. Drilled is the balance. You don't like it buy a Honda.
Lexus Test Driver
Joined: Jun 2008
Posts: 1,109
Likes: 40
From: Barrington, IL
I hear JB Weld works perfect for this! Pick some up at Home Depot and give it a try. Just smear some in the holes, the brakepads will polish it smooth. Make sure to drive REALLY fast your first time out to "bake" the JB Weld with heat.
Let us know how it goes!~
Let us know how it goes!~
drill rotors take away mass of the rotors, therefore your making your heat sink smaller=higher operating temperature. In addition, drilling makes rotors weaker, they are prone to crack around the drills.
so yes, drill rotors are mainly for looks (posers), if you want real performance get slotted
so yes, drill rotors are mainly for looks (posers), if you want real performance get slotted
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Intermediate
Joined: May 2011
Posts: 483
Likes: 4
From: AZ
Per Wikipedia:
"Many higher performance brakes have holes drilled through them. This is known as cross-drilling and was originally done in the 1960s on racing cars. For heat dissipation purposes, cross drilling is still used on some braking components, but is not favored for racing or other hard use as the holes are a source of stress cracks under severe conditions."
"On the road, drilled or slotted discs still have a positive effect in wet conditions because the holes or slots prevent a film of water building up between the disc and the pads. Crossdrilled discs may eventually crack at the holes due to metal fatigue. Cross-drilled brakes that are manufactured poorly or subjected to high stresses will crack much sooner and more severely."
"Cracking is limited mostly to drilled discs, which may develop small cracks around edges of holes drilled near the edge of the disc due to the disc's uneven rate of expansion in severe duty environments. Manufacturers that use drilled discs as OEM typically do so for two reasons: appearance, if they determine that the average owner of the vehicle model will prefer the look while not overly stressing the hardware; or as a function of reducing the unsprung weight of the brake assembly, with the engineering assumption that enough brake disc mass remains to absorb racing temperatures and stresses. A brake disc is a heat sink, but the loss of heat sink mass may be balanced by increased surface area to radiate away heat. Small hairline cracks may appear in any cross drilled metal disc as a normal wear mechanism, but in the severe case the disc will fail catastrophically. No repair is possible for the cracks, and if cracking becomes severe, the disc must be replaced."
"Many higher performance brakes have holes drilled through them. This is known as cross-drilling and was originally done in the 1960s on racing cars. For heat dissipation purposes, cross drilling is still used on some braking components, but is not favored for racing or other hard use as the holes are a source of stress cracks under severe conditions."
"On the road, drilled or slotted discs still have a positive effect in wet conditions because the holes or slots prevent a film of water building up between the disc and the pads. Crossdrilled discs may eventually crack at the holes due to metal fatigue. Cross-drilled brakes that are manufactured poorly or subjected to high stresses will crack much sooner and more severely."
"Cracking is limited mostly to drilled discs, which may develop small cracks around edges of holes drilled near the edge of the disc due to the disc's uneven rate of expansion in severe duty environments. Manufacturers that use drilled discs as OEM typically do so for two reasons: appearance, if they determine that the average owner of the vehicle model will prefer the look while not overly stressing the hardware; or as a function of reducing the unsprung weight of the brake assembly, with the engineering assumption that enough brake disc mass remains to absorb racing temperatures and stresses. A brake disc is a heat sink, but the loss of heat sink mass may be balanced by increased surface area to radiate away heat. Small hairline cracks may appear in any cross drilled metal disc as a normal wear mechanism, but in the severe case the disc will fail catastrophically. No repair is possible for the cracks, and if cracking becomes severe, the disc must be replaced."
Thread Starter
Joined: Sep 2002
Posts: 4,669
Likes: 359
From: TX
vraa is right. The rest of you guys are funny. The holes are for appearance only because other sports oriented cars have holes. Slots are not significantly better than solid discs in severe use. The milling to create the slots also promotes cracking where the tool begins and ends the cut. It's inescapable and it's simple material science.
Yeah, Porsche's drilled rotors don't show up on their hardcore track cars for a reason. They know they'll crack prematurely.
You might also want to reference Stoptech, Brembo, Wilwood, and other brake system manufacturers for their recommendations on drilled rotors. Every single one of them says do not use drilled rotors on a car used at the track.
Yeah, Porsche's drilled rotors don't show up on their hardcore track cars for a reason. They know they'll crack prematurely.
You might also want to reference Stoptech, Brembo, Wilwood, and other brake system manufacturers for their recommendations on drilled rotors. Every single one of them says do not use drilled rotors on a car used at the track.