morris39

I live in a mountainous region with lots of snow at the higher elevations e.g. ski hills. I shift down the DSG on down-slopes to slow and minimize brake use, usually to no more than 4000 rpm. This is an old habit which I have held w/o questioning. I see many (most?) people using their brakes on long down-slopes. So is it economical to downshift, maybe more wear on engine and gear box? It feels safer, particularly on very twisty and icy roads.There is a saying that " the engine is not a brake" Agree or no?

Darryl Johnson

I don't know if it is safer to use brakes or engine braking, but I can offer this statement from a mechanic several years ago: It costs a lot less to replace brakes than to replace an engine.

My personal take is to use engine braking on shorter, less steep hills and to use brakes on longer and/or steeper hills.

XMetal00

My vote is for the safer and more controlled method on icy slopes, which is to use engine braking no matter the cost. What good is saving your engine if your car is off a cliff?

The saying that "the engine is not a brake" applies to those that constantly does it on a regular basis when slowing to a halt on lights - to me this is excessive unless you know the light will turn green when you get there. The statement should not apply to a controlled downhill descend.

Those people that you see using their brakes on long down-slopes are most likely driving slushbox that may not have a clue on what "engine braking" is.

morris39

@ Darryl
The question is really subjective as it is not possible to calculate the relative cost of each choice. The take away here is maybe how confident people about things which are not possible to estimate. Here is an tongue in cheek/absurd thought experiment: Assume trouble free engine life is 100 k miles, wear is proportional to rpm, you engine brake 2% of the time at 4000 rpm vs 2000 normal. How much engine life is lost? 2000 miles (this is a really crazy calc.) Worth considering if it is even remotely correct?
My feeling of greater safety comes from the smoother operation of the car, being able to change the speed gradually and able to accelerate if need be in a tight situation. I could be dead wrong.

dreadlocks

the brake pedal is for slowing down, not maintaining speed.. use your engine on a grade and your brake pedal at the lights.

some of the passes in Colorado will have you riding your brakes at 50mph for 30mins+ if you dont use the engine.. best case you cook your pads and have to re-bed them to get em to stop squeaking, costing a ton of wear and tear on em, worst case you end up not having any way to stop when you need it the most, in many places if nobody saw you go off the road they might not find your remains for years.

superswiss

The general guideline is to be in the right gear to be able to accelerate immediately if you need to make an evasive maneuver and to be ready to accelerate out of a turn. Back when I learned to drive, it was with a manual transmission. Pretty much everybody in Europe gets their driver license by learning with a manual transmission. I was taught to use the lowest gear possible that closely maintains speed on a downhill slope. It's not about whether brakes are cheaper to replace than an engine, the main issue is that hot brakes don't work as well and eventually start fading and you lose all ability to stop the car. Keep in mind that the e-brake in these cars uses the same rear brake pads, so if your rear brakes overheat, not even the e-brake will stop you. That's more important the longer the downhill slope and the heavier the car, but you never wanna run the risk of heating your brakes to the point where they start fading. Brakes are meant to be used briefly to slow down or stop the car, not to be ridden constantly to maintain speed. That's a ton of friction and heat that gets generated if you frequently stand on your brakes. I grew up in the Swiss alps, and still remember when my parents bought a Mustang. It was an automatic and had terrible engine braking. My dad regularly ended up overheating the brakes and lost stopping power towards the end coming down a mountain. It was truly treacherous at times. Luckily, we never went down a cliff, but that was our family's one and only American car ever, and the only car with a torque converter automatic.

morris39

Yes, what SS said. Actually in the winter when conditions include snow or ice I drive in manual mode. This is probably the only time I use the paddle shifters. I don't seem to have the correct reactions (were is the paddle when when the wheel is not centered?) when driving briskly for fun, so use the stick in manual.

tjacoby

The car engine brakes automatically to try and hold speed on hills - I figure if it's programmed to do it, go for it. we have lots of 10-15% grades here and I use a mix of both techniques. always trying to give time for the brakes to cool down.