Re: [DML] mixing cross-drilled brake rotors

[Mark Noeltner <mark@xxxx>]

I won't claim to be a brake system engineer or anything, but here is what
I've picked up during my membership in the SCCA and spending some time
hanging around the track and helping to crew a car:

You might get more oversteer if the cross-drilling does increase the
performance of the front brakes, but only under extreme circumstances. I
doubt that you'll notice much of a difference in normal street driving,
assuming that you had very good brakes on the car before. If you do find
that the brake feel isn't quite what you want you can adjust it by changing
to different pads. You WILL notice quite a bit of difference in the brakes
if it's been a while since you last did a brake job on the car, and the
natural tendency is to credit that change to the drilled rotors. But, in
back to back tests that I have seen, the difference between cross-drilled
rotors and a set of new non-drilled rotors was very slight under normal
driving.

Usually you will only get INCREASED braking force from cross-drilled brakes
under extreme heat conditions when the cross drilling will allow the rotors
to cool quicker. That was the whole idea behind this; to cool the brakes
faster on the track. The street guys picked it up because the drilled
rotors look cool. But on the street you don't normally get the high heat
situations that you do on the track. You can actually decrease braking
force slightly by having reduced the swept area by drilling holes.

Anyway, I would say to put them on if you like them. Try it, then adjust
the brakes using different pad compounds on the front vs. the rear to fine
tune it.

Mark N


At 01:45 AM 4/23/01 -0400, you wrote:
>I specifically want to know if the braking characteristics of having
>cross-drilled rotors only on the front will interfere with the front/rear
>brake proportioning. If the front brakes worked better than designed, and
>the rear brakes worked normal, then could that make the car more prone to
>oversteer?
>
>Walt Tampa, FL
>
>