When is it correct to down-shift?

Dear Car Talk

Dear Car Talk | Dec 01, 1991

Dear Tom and Ray:

A friend and I have been arguing about the long term effects of constantly down-shifting to slow a car rather than applying the brakes. My argument is by down-shifting, you put unnecessary strain on the engine and transmission. My friend's argument is that he's saving himself a brake job, and that the engine and transmission are made to withstand such treatment. Who's right?

RAY: Neither one of you is entirely right, Larry. You're right that downshifting is NOT an economical substitute for braking. But you're wrong about the reasons why.

TOM: The engine and transmission ARE made to withstand this kind of treatment. In fact, they couldn't care less whether you downshift or not. It's the CLUTCH that your friend is going to wear out.

RAY: Downshifting, even if done very carefully (and most people don't do it carefully), puts a lot of wear and tear on the clutch. Your friend may be pleased to find out that he doesn't need brakes next time he visits his mechanic, but he's going to be awfully grouchy when he finds out he needs a $400 clutch.

TOM: Buy your friend a copy of our new book, CAR TALK (better yet, just take him into a bookstore and get him to read it there...don't actually waste your money buying it). Get him to read chapter 9, which is called "Making It Last." If he isn't convinced after that, walk him over to the "Self Help" section of the bookstore and get him something like "The 12 Step Program to Stop Being a Knucklehead." That one worked pretty well for my brother.

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