Dear Tom and Ray:

My wife's grandfather drives like an idiot. Specifically, he never touches the brake pedal until the very last second, at which point he slams on the brake, throwing everyone forward and sending various objects hurtling about the car. Someone finally asked him what he is thinking, and he replied that he is prolonging the life of the brakes. His theory is that if he slams on the brakes, lurching the car to a fast, screeching halt in a second, it means less time for the brake pads to be rubbing and thus wearing down. If he gradually eases the car to a nice, sane stop, it means all the more time for the brakes to be wearing down. Of course, he's crazy, right? Or could he be on to something?

-- Ian

RAY: Maybe he doesn't like you guys, Ian. Perhaps his real goal is to get you all to stop riding with him. In which case, it's not working yet. Tell him he needs to wait a few seconds longer before slamming on the brakes.

TOM: He's nuts, Ian.

RAY: The amount of wear on the brake pads can be calculated by multiplying force times distance.

TOM: So, using more force over less distance (like he's doing) is really the same as using less force over more distance (like the rest of the sane population does).

RAY: In other words, he's making you bang your foreheads on the dashboard for nothing.

TOM: In fact, he even may be shortening the life of his brakes. By repeatedly causing a rapid rise in temperature from all that friction, he could cause warping or cracking of the brake lining material.

RAY: He's also damaging other parts of his car by jamming on the brakes. By making what essentially are "panic stops," he's stretching things like suspension parts and motor mounts to their limits, and shortening their lives.

TOM: Not to mention all the extra money he's going to have to spend on carpet cleaner after he makes you guys carsick.

RAY: Tell him that if he really wants his car to last a long time, the best way to drive it is gently. Start gently, anticipate turns and stops, and slow down gently.

TOM: And tell him this also increases the likelihood that his progeny will come to visit him occasionally when he's in "the home."