GLAMOUR ROTORS

GLAMOUR ROTORS

 

by Pat Goss

 

So you want some racy cross-drilled or slotted brake rotors? But do you really? After learning the pros and cons of glamour rotors

most drivers decide not to spend the extra money. The positives of slotted and cross drilled rotors are mostly great looks when the car

is standing still. They may also have some advantages at the track — but even that’s limited because slotted and drilled rotors have

more negatives then positives when used with modern ceramic based brake pads.

 

Specialty rotors do not make a car stop in a shorter distance because what actually controls how well a car stops is its tires. As long as

the brakes can lock up they’re doing all brakes can do. Drilled and slotted rotors may actually increase stopping distances because

they reduce the contact area between the pads and the rotor surface.  More holes less rotor surface for the pads to grab. But do the

holes help dissipate heat? No!

 

The rotor is a metal heat sink that dissipates braking heat. Drill holes in the rotor and you reduce the amount of metal to absorb and

dissipate heat. More holes less heat transfer. Some say the holes create air cooling — WRONG! Metal transfers a lot more heat than

air. So — if you want the look buy drilled or slotted rotors but don’t buy them thinking your car will automatically stop better.

 

© Copyright 08/19/16 Pat Goss all rights reserved

8 comments

November 4, 2017 at 7:36 pm

Great info, Pat. Always appreciate your talks on Motorweek.

John Dedman said:

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November 5, 2017 at 6:46 pm

Some rare common sense regarding brake changes and upgrades. Thanks Pat.

Donald Roy said:

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November 6, 2017 at 9:45 am

Wow! Thanks Pat for this great info.

Vincent Hill said:

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November 6, 2017 at 9:47 am

I have Cross Drilles Rotors on my Motorcycles and A Few Cars. My understanding was the Holes did “2” Things. Decrease the Gas that can build up under a Pad and in rainey weather allow for more dissipation of the Water Faster. I am using Carbon Metallic Compound Pads.

charles woznak said:

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November 6, 2017 at 9:53 am

I’m glad I didn’t spend the money when I did my truck. Thank you for all the great education you provide pat.

Art Barte said:

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November 6, 2017 at 4:02 pm

This explanation makes good sense – more metal does mean better heat dissipation over air cooling. Also, I wondered about the holes and slots weakening the rotor’s rigidity and increasing wear on the pads. Thanks, Pat!

November 6, 2017 at 6:12 pm

Pat, I forgot to mention I put slotted rotors on my car abt 4 years ago. I have no problems stopping with them, however, I also fitted 18″ wheels and performance tires at the same time. I think one has to have a balanced approach and go full force when adding exotic items to a vehicle. Still liked your comments, though.

Marcy said:

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November 7, 2017 at 11:31 am

David:

Balanced approach is something I tell drivers about all the time. Adding bigger breaks does nothing (other than give more resistance to fade) for stopping distance because they do not change the grip of the tires. Regardless of the size or quality of the breaks unless you do something with the tires they will lose traction at the same level of force and the car will take the same distance to stop. Best approach is to modify tires first and see what happens to stopping distance then if needed modify the brakes. If the car is used at the track big brake, slotted rotors and cross drilled rotors can be a must have but on the street in normal driving they are mostly cosmetic.

My big gripe with these kits is that many brake shops are selling them to customers who don’t need them, don’t modify tires or other factors that effect braking yet are told they will have much shorter stopping distances and be protecting their family.

Pat

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