RZ28

Do cross drilled rotors improve wet braking?

mitchntx

iTrader: (14)

No ... tires will slide on wet pavement way before your braking performance is degraded by water intrusion.

trackbird

iTrader: (4)

<~~~~I'm with Mitch!

LS1Maniac

They couldn't hurt!

RZ28

I figured they would help wet braking because upon initial application of the brakes in the rain, any water on the surface of the rotors and pads would be immediately pushed into the holes and the pad would make quicker contact with the surface of the rotor. Without the holes, water trapped between the rotor and pads would have to be squished out the sides of the pads, this would delay braking until the water was removed and then the pad material can make solid contact with the rotor surfaces.
Please explain why this wouldn't be the case?

technical

The only way water will get on the brakes/rotors is if you are going very slow through a deep puddle. At speed, your tire will disperse the water. Unless you are running slicks, then you'll just hydroplane.

RZ28

I think water must be getting on the brakes/rotors during rains, otherwise
1) I wouldn't feel the loss of brakes upon initial application while driving on an expressway,
2) many experts tell drivers to tap on the brakes once in a while to dry them off in the rain,
3) some new Mercedes models (SL600) automatically apply the brakes once in a while when the car senses rain to dry off the rotors:
SENSOTRONIC BRAKE CONTROL
The future of automotive braking technology is here. With electronic control of
high-pressure hydraulics, Sensotronic automatically determines the most effective
braking force to apply at each wheel, adding up to better handling and composure
when you might expect drama. Even under normal braking, Sensotronic precisely
modulates the brake pressure to bring you to a smooth stop. Turn on the windshield
wipers, and Sensotronic periodically and imperceptibly
applies the brakes to keep them drier and ready for
action. Sensotronic can even respond before you touch
the brake pedal. Lift your foot off the accelerator quickly,
and Sensotronic sets the brake pads closer to the discs
for instant response.

jRaskell

iTrader: (1)

^ Gimmicks.

John95Z28

^ German techno-crap. I bet you need a 2nd mortgage on your summer cottage in the Hamptons just to get the brakes serviced. Mercedes should concentrate on engineering a sedan with a curb weight under 6000 lbs, and leave the bloated, over-wrought gimmics to Lexus. Enough with the motorized cupholders and air-conditioned glove boxes!!

mitchntx

iTrader: (14)

Have you ever put clothes in a washing machine?

What happens when they finish washing and rinsing?

They go through a spin cycle ... why?

So that centrifugal force will force the water out.

At 50mph, how much water do you think is actually on the surface of the brake rotor? Just how far off the surface of the rotor do you think the brake pads ride?

VIP1

Exaclty. The pads are prety much in constant (although no pressure) contact with the rotors. Plus the centrifugal force will sling off the water.

Here is some more info on slotted/drilled rotors:
https://ls1tech.com/forums/showthrea...ighlight=rotor
http://home.columbus.rr.com/trackbir...led_rotors.htm
(Thanks trackbird)

trackbird

iTrader: (4)

No problem. I'm glad to see it has been useful.

CaptUSA

iTrader: (5)

[QUOTE=VIP1]Exaclty. The pads are prety much in constant (although no pressure) contact with the rotors. Plus the centrifugal force will sling off the water. [\QUOTE]


I'm going to have to dis-agree w/ that one. What a waste that would be. The pads don't ride on the rotors. And to the poster, your logic is solid don't let em shake you..... HOWEVER.... The water is going to be pretty much vaporized the second contact is made anyway. Any improvement from drilled rotors would be minimal. And one could actually make the argument that the holes would trap the water, which would vaporize, and put outward pressure on the pads, ergo DECREASING the effectivness of your breaks. LOL It's all Just get what you want. Whatever you get has to be certified by D.O.T. first anyway, so it'll be safe. Just my $.02

technical

[QUOTE=CaptUSA]Have you ever changed brake pads? The pads do touch the rotors at all times. Even when you are not applying the brakes. It is a waste, but it does happen. Floating calipers are the worst, but even fixed calipers do it.

mitchntx

iTrader: (14)

You people crack me up ....

jRaskell

iTrader: (1)

I like your washing machine analogy Mitch. I wanted to comment on that myself, but couldn't come up with something easily understandable off the top of my head at the time. Kudos.

RZ28

I think on cars with thin spoke wheels exposing the rotor to the elements are more prone to losing that initial bite in the rain. Some of you must have experienced that faded brake feeling the first second you hit the brakes when driving on the highway in the rain, that's why they teach you to periodically tap the brakes in the rain to keep the rotor/pads dry.

Certified by D.O.T. ???? Yes, the ones from large companies such as Raybestos and Brembo and maybe the virgin blank rotors are DOT certified, BUT I DOUBT ANY of the rotors drilled and cut by the sellers on ebay and sponsors are DOT certified. (Who knows if they drill through the internal vanes and decrease the structural integrity of the rotor.)

[QUOTE=CaptUSA]

mitchntx

iTrader: (14)

Who is "they"? High School DE or some driving school you've attended?

I've never heard of such a thing. BUt that doesn't mean much.
I'm certainly no expert ... I like learning new things ...

NOBR8KSS

iTrader: (12)

I think most people who are really hard on brake rotors and pads (road racers) will agree that drilling the rotor really doesn't add a measurable performance advantage to braking effectiveness. Additionally, on the street where pad and rotor temperatures will (hopefully) never reach the level they will on a road course, they would show even less of a performance advantage.
Slotting the rotors has been shown by the big brake companies such as Baer, Stop-Tech, Brembo, and SSBC to add performance in extreme conditions where the pads begin to vaporize and develop a layer of gas between the pad and rotor. Slotting allows this gas to escape. I am referring to very hard, repeated braking...nothing that would ever occur on the street.
On a street rotor, slotting and drilling is for appearance. I think one of the best setups going right now is the Brembo OEM replacement rotor with a quality ceramic pad. It's not flashy, but it's inexpensive and serves it's purpose.

What a lot of people don't understand is that TIRES are the weak link in most braking systems. If you can lock up your tires with your brakes, then you need better tires. Of course, that only goes so far on the street, as street tires aren't near as sticky as a track tire.

technical

"They" are those people in front of you who keep tapping their brakes and making you late for work.