Driving down a steep hill, which is better: braking or downshifting?

Dear Car Talk | Aug 01, 1992
Dear Tom and Ray:
Mary
RAY: Our advice is to keep doing exactly what you're doing, Mary. When you're coming down a long, steep hill, it is not just advisable, but almost imperative that you put the car in a lower gear. When you do that, you use the compression of the engine to slow the car down. That means you don't have to stand on the brakes all the way down the mountain.
TOM: If you constantly ride the brakes down a long, steep hill, there's a real danger that the heat from the friction of the brakes will cause the brake fluid to overheat and even boil. That's very serious, because it can cause complete brake failure.
RAY: So what you're doing is absolutely correct The sign really should advise trucks AND cars to shift to a lower gear. They probably figured that car drivers would be smart enough to figure it out for themselves...but after hearing about your friends, I guess they're going to have to reconsider.
Mary
RAY: Our advice is to keep doing exactly what you're doing, Mary. When you're coming down a long, steep hill, it is not just advisable, but almost imperative that you put the car in a lower gear. When you do that, you use the compression of the engine to slow the car down. That means you don't have to stand on the brakes all the way down the mountain.
TOM: If you constantly ride the brakes down a long, steep hill, there's a real danger that the heat from the friction of the brakes will cause the brake fluid to overheat and even boil. That's very serious, because it can cause complete brake failure.
RAY: So what you're doing is absolutely correct The sign really should advise trucks AND cars to shift to a lower gear. They probably figured that car drivers would be smart enough to figure it out for themselves...but after hearing about your friends, I guess they're going to have to reconsider.
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