JMSudela

From time to time, I downshift (gradually) when approaching red lights to reduce speed as opposed to just applying the brakes. Are there any downsides to this practice?

GSteg

iTrader: (15)

Unless you're going down a long hill, just use your brakes. It's cheaper to wear out your brake pads than transmission.

mmarshall

With heavy brake use, it might not just be an issue of pad wear, but also of rotor-warp from heat buildup. Turning brake rotors on the lathe (providing there is enough metal left on the rotors to safely do so) can run into some money...new rotors, even more. But I agree, in most instances, it is less than a new or rebuilt transmission.


If you DO decide to downshift and let engine-compression hold your speed back, unless you have one of the few newer vehicles with automatic rev-matching downshifts, blip the throttle lighty as you downshift to try and match the engine-speed to the transmission-speed as much as possible. This will minimize driveline-shock as the engine-RPM bumps sharply from the downshift....it is similiar to what is called a heel-and-toe downshift (or double-clutching) in a manual-transmission vehicle to save wear on the synchronizers.

Also, as GSteg correctly points out, there are some long steep hills where, because of their length or steepness, it is preferable NOT to use the brakes, but simply to downshift and stay in a lower gear all the way down (like some heavy trucks do). In the Eastern part of the U.S., Pennsylvania and West Virginia, in particular, have some noted long, steep grades in the Appalachians. One of the most notorious is the famous 3.5 mile, 9-10% grade-descent of U.S. 40 into Uniontown, PA from the top of Chestnut Ridge/Mt. Summit. This hill is an absolute beast, even for some regular cars, and will simply destroy your brakes if you don't downshift at the top before starting down.

chikoo

it depends. if you are downshifting to gears that are appropriate for the speed of the car, it works. but downshifting aggressively from 6 to 4 while at 40 mph, and then 4->3 at 30mph is not good.