# Forum > Discussion > Mad Science and Grumpy Technology >  Car Brake question

## Traab

I had a question for the gearheads out there. When going down a long steep hill, whats the best way to handle it in a standard car? Shift into lower gear, coast till you hit whatever your max allowable speed is, then brake firmly to slow down, release the brake and coast again? Or keep light to medium pressure on the brake full time to maintain the same speed? Which degrades brakes more? As an example, the hill i go down, I generally shift to a lower gear, coast to 55, brake to 45, then coast till 55 again. Im pressing the brake for like 3 seconds each time to drop the speed then coasting for roughly 15 seconds before I repeat. Is hitting the brake harder but less often better for maintaining brake life than less but constant pressure?

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## veti

I'm not a petrolhead by any means, but I know how to search for this kind of question...

Answer seems to be "it depends".

With prolonged, soft braking, there's a danger of something called "brake fade" caused by overheating. If it's a blazing hot summer's day, and you've been in stop-go traffic for a while, and you've got a particularly long hill to coast down, then that may be something to worry about. (I've experienced it myself in those conditions, and it's frickin' scary.) But in other conditions, it's probably unlikely to be a factor. 

As for maintaining brake life - I have no idea. I would focus on the most reliable way to maintain control of the car, because even a minor accident is likely to cost a lot more than some new brake pads.

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## Aedilred

> I had a question for the gearheads out there. When going down a long steep hill, whats the best way to handle it in a standard car? Shift into lower gear, coast till you hit whatever your max allowable speed is, then brake firmly to slow down, release the brake and coast again? Or keep light to medium pressure on the brake full time to maintain the same speed? Which degrades brakes more? As an example, the hill i go down, I generally shift to a lower gear, coast to 55, brake to 45, then coast till 55 again. Im pressing the brake for like 3 seconds each time to drop the speed then coasting for roughly 15 seconds before I repeat. Is hitting the brake harder but less often better for maintaining brake life than less but constant pressure?


I was taught to shift to lower gear and rely primarily on engine braking, reserving the footbrake for adjustment and control, principally I believe out of concern over brake overheating as mentioned by veti above. If I find that I'm still going so quickly I need to apply the footbrake a lot, I'll switch down to a lower gear. I have no particular qualms about taking a hill in second gear if necessary.

I don't actually know which method is better for preserving the brakes, but as a matter of common sense, if you have no engine braking and are relying entirely on the footbrake for speed control, I would have thought that is always going to wear the brakes more, so always switch to the lowest gear you feel comfortable with anyway, regardless of what you end up doing with your foot.

Edit: Under the UK highway code at least, "coasting" is defined as driving _not in gear_ and that is always a bad idea. From context I assume that here you mean "driving in gear but without applying accelerator or brake" which is obviously perfectly fine (context-dependent).

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## Yora

You can always just drive with the foot on the clutch pedal. I do that all the time when slowing down on flat ground. Nothing sketchy about that.

Doesn't engine breaking put stress on the clutch and gearbox? If I were concerned about wear on my car, I'd be a lot more worried about those parts than on the break pads and disks, which are specifically designed to handle such stresses and much cheaper to replace when they are worn out.

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## Radar

> You can always just drive with the foot on the clutch pedal. I do that all the time when slowing down on flat ground. Nothing sketchy about that.
> 
> Doesn't engine breaking put stress on the clutch and gearbox? If I were concerned about wear on my car, I'd be a lot more worried about those parts than on the break pads and disks, which are specifically designed to handle such stresses and much cheaper to replace when they are worn out.


No more stress than when the engine pushes the car forward. Most likely even less than that. Engine breaking also saves fuel as the minimal rotation speed of the engine can be maintained without any fuel being used.

edit: also keep in mind that on a long and steep downhill you really do need engine breaking - otherwise the risk of overheating the brakes is pretty high.

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## factotum

I use as low a gear as possible. My car isn't red-lining in third until 70+ mph and there's usually enough engine braking in that gear that I don't need to even touch the brakes, so that's what I do.

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## tomandtish

I actually submitted this question to Mythbusters back in the Jamie/Adam days. Unfortunately it was during their last season so never heard anything.

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## Lord Torath

And Click'n'Clack retired over a decade ago.  There might be something in their archives.

I generally come in on the side of "brakes are much easier and cheaper to replace than transmissions."  I tend to hit the brakes hard enough to get me a few mph under the limit, then release until I get a handful of mph over the limit, and repeat.

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## Aedilred

> You can always just drive with the foot on the clutch pedal. I do that all the time when slowing down on flat ground. Nothing sketchy about that.


This is the same as true coasting, i.e. driving not in gear. While you can often get away with it, it's deprecated in practice because you have less control due to lack of engine braking.





> Doesn't engine breaking put stress on the clutch and gearbox? If I were concerned about wear on my car, I'd be a lot more worried about those parts than on the break pads and disks, which are specifically designed to handle such stresses and much cheaper to replace when they are worn out.


Yes, engine breaking is bad for your car. Engine _braking_, on the other hand...  :Small Wink:

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## Storm_Of_Snow

Go down the hill in the same gear you'd come up it. Using the brakes alone means you're relying on the brakes not fading or totally failing, and the road surface not suddenly becoming slippery.

Really steep hills and you're driving a manual transmission, then also keep your hand on the gearstick to make sure it doesn't jump out.

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## sktarq

> Doesn't engine breaking put stress on the clutch and gearbox? If I were concerned about wear on my car, I'd be a lot more worried about those parts than on the break pads and disks, which are specifically designed to handle such stresses and much cheaper to replace when they are worn out.


Yes but many cars with manuals are designed for that as part of their expected use along with the other stresses expected. For quite a while US car companies didn't do this as a priority and so the idea that "engine breaking bad" got into the car culture but those days are decades ago. That said HEAVY engine breaking can be very damaging if you mess it up, it is much less actively taught, and so a trickle of horror stories keep things going. 
Engine breaking is good for mild longer term speed changes. . . keeping your car from accelerating as it rolls down down a moderate hill is almost an ideal case for it.  

Go down same as you up is a generally good rule of thumb but does require getting used to (you will start to speed up when you push the clutch and may spend little time with the throttle depressed)

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## Traab

Just to add that my car is an automatic so no clutch pressing for me. Also being an automatic, the gear labeling is squirrely. I go D, S, then 2 and 1. (Or is it 1 and 2? I forget, I never use them) So I shift from drive to S when going downhill for the engine braking effect then put moderate pressure on the brake to slow it down a good 10-15 mph then take my foot off the brake and let it slowly reach the max speed im traveling at and repeat. I knew brake fading was a possible issue, though the hill im on isnt THAT bad, its basically a mile downhill in a straight line with a sign at the top warning truckers to use a lower gear. I just was more concerned with long term brake longevity and what the better option is there. Sounds like nobody is really sure about that. Guess I will just stick to my usual then. Seems like a better habit to be in overall anyways.

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## Imbalance

The one long hill on my daily commute drops a good 900 feet in elevation, with traffic lights and a roundabout.  The longest stretch without a stop is also the steepest.  There are rare mornings where I do not have to stop due to timing the greens, but there is naturally always cause for both wheel braking and engine braking.  I can tell you after seven years with the same car that front pads usually last almost two years, and that the drive train has over 180,000 miles with no major issues, for whatever that's worth.

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## Witty Username

What would heavy engine braking be in this context?

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## gbaji

> What would heavy engine braking be in this context?


I'm assuming that's dramatically down shifting (trust me, you'll feel it). This can be damaging, since it puts a lot of stress on the system. You're basically shifting the speed/torque ratio (which will feed back from the transmission to the motor) so you want to do this gently. There's always a range of speed/rpm that you want for any given gear on the transmission, and you want to stay inside that range, but leaning towards one side or the other depending on whether you are slowing down or speeding up. And yeah, you mostly just do this by feel.

Also drive an automatic these days, though I can manually shift if I want to (6 speed, sport and manual modes). Honestly? Unless you are driving a largish truck and/or carrying a heavy load, there isn't a whole lot of risk to just using the brakes when going downhill. They are designed to stop the car completely, and yes, even while there's some engine force pushing forward (trust me, my car will move forward/backwards while idling on a flat).

I would recommend the "brake for a bit, slow down, then release" method though. It serves two purposes:

1. Reduces/prevents brake overheating and fading. Honestly though, with modern braking systems on a standard sized passenger car, unless you are holding the brakes down for a long time (several minutes) while also accelerating (pushing both gas and brake at the same time), you're rarely ever going to run into this problem. But yeah, on long steep hills, it's a good idea to not just have the rotors and pads sliding along in contact the whole time. You know. Just in case.

2. Gives clues to the folks behind you as to when you are actually braking. Holding them down lightly the whole time is basically riding your breaks, which gives no information to the person behind you as to how *quickly* you are breaking. Nothing worse than being behind someone who's had their brakes on constantly for the last 30 seconds or so, maintaining a consistent speed and then suddenly they break hard. The brake lights give a clue to the person behind you that you are changing speed. Periodically pressing on the brake creates an interrupt to the person behind you, which will (hopefully) cause them to check relative speed and adjust. Holding them down lightly all the time while driving gives them no information at all. You may as well not have brake lights on your car.


Honestly. I put 2 as far more important than 1. But both are valid reasons for doing it this way. Again, assuming we're using our brakes in addition to whatever else is going on (which could include engine braking). Also, if we're being complete, we should consider electric cars and regenerative braking, in which you're actually technically engine braking anyway (but using the resistance of an electric motor to do so). I'd still also use the "brake then release" method here (for the same reason in 2 listed above). If you've ever tried to drive behind someone on a downhill who is riding their brakes the whole time, rarely do you think "darnit, they're going to wear out their pads". It's always "darnit. I can't tell if/when this idiot is actually going to slow down", which usually results in a pretty white-knuckled trip down the hill, requiring extreme vigilance on your part "just in case" the person in front of you suddenly stops.

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## Hof

While I cannot say anything to the science of the matter, I do have some anecdotal information.

Some years ago I was on holiday with several friends in the Belgian hills using three cars. One of the drivers was a bit green, having gotten his license only recently.
He used his brake all the time, not shifting down in gears. The rest shifted down one or two gears, depending on what they felt the engine could easily take.

At some point we needed to make an emergency stop, because one of the brakes was actually burning.

All in all I'd say use the brakes when needed, but don't rely on them alone.

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