While driving, when is better to slow down by applying brakes vs. shifting into a lower gear?
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Anonymous
ANSWERS: 2
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Slowing down using brakes uses all 4 wheels and includes parts designed to keep the rear wheels from locking up. If the rear wheels lock up it is very easy for a car to spin out. Slowing down by down shifting only uses the rear wheels and can lock up the rears causing you to spin out. On top of that the brakes of a car are relativity cheap and easy to replace. If you slow down by down shifting you are using the clutch which is much more expensive and harder to replace. Short answer.. Use the brakes! EDIT!! After discussion with several co-workers I will change my answer slightly. Af sar as wear and tear, I have been assured that downshifting makes little difference in clutch wear. If this is the case, then the braking effort is free and can save on brake pads. I will still stand by on the spin-out issue for a rear drive vehicle. On a front drive, downshifting can lock the fronts, causing loss of steering. Downshifting also has no ABS function (with a very few exceptions). My revised answer would be. Downshifting can reduce brake wear when used properly but should be used VERY carefully if it is slippery.
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Engine braking from downshifting isn't nearly as efficient as using the brakes. Brakes work on all 4 wheels, usually have ABS these days, and can slow you down much more rapidly than engine braking. Where engine braking becomes useful is maintaining a lower speed and minimising the use of brakes on downhill slopes - hence part of the reason semi trucks have jake-brakes (exhaust brakes). Going down a hill in a higher gear and riding the brakes to keep your speed down will overheat them and cause them to eventually fade. If you combine engine braking and occasional brake application to keep your speed down, your brakes will last much longer. Some automatic cars do have decent engine braking if you shift the lever down to '2' or 'L' (depending on how fast you're going - don't over-rev the car by selecting a gear too low).
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