2012 Chrysler 300 SRT8 Special White Edition

By Russ Bond

When the roads are wet or snowy, the braking distance for any vehicle increases. That is because the grip of the road surface is lower than it is on dry pavement. But a closer look at brakes reveals that there is also another issue at play.
You see, the water isn’t only on the road. As you travel down the road, the water gets washed up into the car’s underside and can cause some problems — one of them being cold brakes.
To understand the problem of cold brakes you have to understand just how braking systems work. Braking is much more than just the brake pad coming in contact with the brake rotor: there is a thermal element that has to work properly. Brakes don’t work as well cold as when they are hot. They also don’t work very well when there is water on the disc, which a) cools the disc down and b) gives it even less grip (read: stopping power) than if it were dry.
Chrysler has come out with what it calls Rain Brake Support. New for 2011, the system uses the Electronic Stability Control (ESC) pump to occasionally push brake pads lightly against brake rotors in rainy conditions in order to keep rotors dry and assure maximum braking performance under wet conditions.
The main computer receives a signal from a sensor that lets the computer know that the car is travelling in wet conditions. Then the computer sets the Rain Brake Support program in motion, which actually applies pressure to the brake system — like you stepping on the brake pedal — which moves the pad out to the rotor and lightly scuffs the rotor so that the moisture is removed.
The key here is that when the pad hits the rotor it generates heat, and that heat is used to absorb any further water that comes in contact with the rotor. This process is repeated for as long as the rain sensor detects moisture.
The benefits to you, the customer and driver, are twofold. First, should you need the brakes, they are in the optimum working temperature range. Secondly, a brake that is instantly ready to work will shorten your braking distance in wet conditions.
You will really feel the effect if you travel for a long distance on a highway (where the brakes aren’t used) and, when you come to the off ramp, your brakes are at the best they can be because of the Rain Brake Support system.
Cars and drivers are at their most vulnerable when the outside weather conditions are wet or icy, and with the Rain Brake Support system, you are just that much safer.

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Tags: brakes, braking systems, Electronic Stability Control, ESC, Rain Brake Support system