Does Downshifting (Engine Braking) Cause Extra Wear and Tear?

Question

Does the act of downshifting to slow your vehicle down have any negative side affects?

I don't downshift more than one or two gears at a time and I let out on the clutch slow enough that I don't rev very high. My red line is at 5.5 and mine are around 3 - 3.5 when I do it. This process makes my brakes last much longer but I'd like to ensure it's not at the cost of something else.

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Edit:
Thanks everyone for your answers, but I'm seeing very conflicting information. I found this on wikipedia but then again it's wikipedia. Does anyone have anything to support their thought one way or another?

Engine braking passively reduces wear on brakes and helps a driver maintain control of the vehicle. Active use of engine braking (shifting into a lower gear) is advantageous when it is necessary to control speed while driving down very steep and long slopes. It should be applied before regular disk or drum brakes have been used, leaving the brakes available to make emergency stops. The desired speed is maintained by using engine braking to counteract the gravitational acceleration.

Answer 1

Most of the time when you drive, you're putting a load (and causing wear) on what I'm going to call the "forward" face of each tooth on each gear in your drivetrain. The front of a tooth on the crankshaft pushes against the back of a tooth on the next gear in line, which pushes the next gear, etc. When you use "engine braking", all you are doing is engaging the teeth in the opposite direction, and putting force and wear on the faces that normally are just along for the ride.

Now, does that mean you're wearing your engine out faster? Marginally... but the parts you're wearing out would normally have to be replaced (if at all) because they'd worn out from the other side; you're wearing surfaces that would usually be thrown out with hardly any wear at all. To borrow a phrase from the medical field, your engine/transmission will die with that wear, not of it.

To the people who say that you're transferring the wear from your brakes to your clutch, all I can say is... you're doing it wrong! If you downshift as quickly and smoothly as you upshift, then the added wear and tear on your clutch will be a statistical blip - seriously, how many times do you downshift for this reason, as opposed to normal shifting? (If your answer is "at every light", then the poster who advised you to calm down your driving habits had a point.)

Having said that, there's a seriously wrong way to do this; I used to do it when I was first learning to drive stick, and it was incredibly stupid: pushing the clutch all the way in and letting the RPMs fall to idle, then letting the clutch out and allowing the engine to slow the car down in the same gear. If that's how you're doing it, STOP IT! That way wears out the clutch very fast (which might be what the other posters had in mind), drops your speed dramatically without lighting up your brakelights (I confess, that's why I started doing it - trying to sneak-slow past a cop), and runs a high risk of stalling the engine and seriously ^&*@ing something up. Don't be that guy.

Answer 2

Most of the time you won't need heavy braking in traffic.

You can avoid stopping and starting by:

• Driving more calmly
• Leaving plenty of distance between you and the vehicle in front (even at low speed)
• Simply taking your foot of the accelerator early

If you let the car slow down, and use the gear until it is no longer appropriate (too slow that the engine starts to struggle), then change down, you will always be in the right gear. This will transfer very little shock through the clutch or transmission. You can still use the brake but you don't need as much.

Brake pads wear out much quicker than any gear box will, and the number of brake pad and rotor changes will probably add up to one gear box (over the life of that gear box.) I drive the same way to work everyday. I rarely have to stop and I always beat the lane changers and racers. Drive calmly, and accelerate and brake smoothly. You will get there sooner, with much less stress on your vehicle (and you.) Leaving earlier helps.

I'm a driver trainer/examiner.

Answer 3

If you downshift into a gear at a RPM that is within the norm of driving then no, no harm done. When you downshift what is slowing you down is actually the compression stroke and is recommended over hard braking. Like another said, it is a bit of a mix of the two but engine braking is ok as long as the engine stays under redline, so do not go from 5th to 3rd.

Answer 4

Which would you rather change - your brake pads or your clutch?

By downshifting to decelerate you are trading wear on your brake pads for wear on your clutch (among other things).

Brake pads are much cheaper and easier to replace than a clutch. Personally, having done both, I'd rather do 50 brake jobs before I'd do one clutch job.

Answer 5

First, everyone who said that the braking effect comes from the compression stroke is wrong...the air in the cylinder is compressed which takes energy, yet after top dead center acts as a spring and helps force the piston back down, returning the exact same force as was put into it in the first place. Probably more, actually, since the compression heats the air charge up and causes it to expand, like a very minor version of a power stroke.

No, the braking effect comes from the INTAKE stroke, from the engine drawing air through the closed off throttle-body. It's like trying to suck air through a tiny straw. Braking is from vacuum, not compression. That and a bit of engine friction, which is less significant with modern engines than it used to be.

As for using engine braking, using it mildly for keeping speed on downhills isn't really bad for your car. I'd avoid driving like a rally racer and aggressively downshifting to slow down for every turn or stoplight, but when done right, it doesn't effect anything any differently than driving normally. Yes, it causes more engine revs, but they are no worse than the revs you get accelerating onto an on ramp. If you're planning to keep the car for 250,000 miles, yeah, you might want to keep the revs to a minimum, but otherwise, assuming nothing is wrong with the motor itself, the car will be done-for long before you wear the engine out by adding revs.

The same applies for the clutch...yes, every time you use it, it wears a little, but no differently than using it during normal driving. If you're worried enough about the clutch that you try to keep your car in one gear as much as possible, sure, avoid engine braking. But if you're like most people, you use the clutch 5 times every time you get up to speed, two or three times every time you leave a stoplight. A few more engagments isn't a big deal. And you don't always have to use the clutch; often you just have to let off the gas and leave it engaged and it will work to slow you down.

It will add some wear and tear to the drive train, but like the above, you could consider it the same as driving an extra half-mile every day, only without the fuel cost. If that wouldn't scare you, neither should engine braking.

The only thing that wears out differently is, as the other poster said, the rear faces of the gear teeth, and that really doesn't matter. You use them every time you back up, the rest of the time they do nothing. IF they should wear significantly, the only effect will be that the transmission will be louder when your reverse. And you'd have to put a lot of wear and tear on them to get them that worn out.

Answer 6

Donovan's is the only answer that has any truth in it.

• Downshifting and engine braking will have NO effect on the clutch, as you don't slip the clutch
• it doesn't wear out the engine, as you use the compression stroke
• and it is far better on tyres and handling as any advanced driving instructor would tell you.

It is just more difficult, as you need to coordinate a number of factors, so not suitable for beginners.

Answer 7

You are 100% putting wear and tear on your engine plus transmission. Not only that but you're also increasing the wear on your clutch. Having said that, I rev match every time I downshift. This still puts wear and tear on the components but not as much as physically slowing the car down when bringing it down a gear.

Brake pads are cheaper and easier to replace than a clutch!

Answer 8

I agree with MT_Head's and Donovan's answers, but I'd like to add that the downshift itself can be quite heavy on your synchromeshes if you don't do it right.

When you up-shift, the input shaft drops in speed by ordinary friction, and the synchromeshes don't need to work much in order to match it to the speed of the output gear. However, when you down-shift, not only does all the work of getting the input shaft revolutions up to that of the output shaft fall on the synchromeshes, but they also have to counteract that same friction which normally helps. This is why cars often develop a bad second gear over age (since the second gear is the one most commonly down-shifted into).

If you want to downshift frequently without wearing out your synchromeshes, you should learn to double-clutch correctly and as such RPM-match the transmission against the engine manually instead of letting the synchromeshes do that work for you. When you downshift, do as such:

1. Disengage the clutch once and let the transmission into neutral,
2. Engage the clutch again.
3. Rev up the engine to the approximate revolutions you'll need on the new, lower gear; or perhaps a little higher to give yourself headroom for the next step. (This is preferably overlapped with steps 1 and 2.)
4. Disengage the clutch once again (hence double clutching) and shift into the lower gear. If you've RPM-matched correctly, you'll feel the gear just falling effortlessly into place, rather than needing time to rev up the input shaft.
5. Engage again and continue driving.

If you're not used to driving like this, it may sound a bit burdensome, but it doesn't take a vast lot of training to get used to it, and once you do, you'll find that you can actually downshift faster than without anyway, since this method of downshift synchronization is usually faster than what most synchromeshes are capable of. And it really does make your transmission age a lot better, especially if you downshift a lot.

Answer 9

If you double-clutch the downshifts and ensure that the engine is running at exactly the right speed before you engage the clutch, any additional wear will be insignificant. Double-clutching will, if done properly, eliminate any additional wear of the synchronizers and if the engine is running at just the right speed before you engage the clutch after the downshift, the clutch will not have to drag the engine up to speed.

Here's how to double clutch:

Declutch and shift to neutral.

Engage the clutch and, at the same time, use the accelerator to bring the engine up to the proper speed for the gear to which you will be downshifting.

Declutch and shift to the lower gear

Quickly engage the clutch.

If you do it just right (which may take practice), the shift lever will easily move to the selected gear and engaging the clutch will be totally smooth. Eventually, the operation will become totally automatic.

Answer 10

Short answer is yes. You are running the engine through more revolutions that you would have done if you had used your brakes. This is adding wear and tear to your engine. Not sure about the transmission.

Now from a cost savings perspective the wear that you save on your brakes might actually be more than the small amount of wear that you add else where. There might even be a fuel savings by having the vehicle momentum power the engine.

One negative of doing this is that drivers following you have no visible warning that you are slowing down. (Using your brakes will engage your brake lights).

Answer 11

Just some anecdotal evidence. I downshift at least a few times a day. Only one gear at a time and never send my tach anywhere near the red, BUT I NEVER RIDE THE CLUTCH. Unless it is an emergency I'll downshift and come off the clutch almost as quickly as I do when I upshift, If I'm going to fast for this I don't downshift yet, UNLESS IT'S AN EMERGENCY.

Ok all that being said here's my anecdotal evidence. I have 180000 miles on my pontiac vibe and from what I hear the clutch goes on average around 90k. Mines still going strong. I'll regret posting this if it goes tomorrow.

Answer 12

Some answers correctly identified wear of synchronizers as a possible concern on manual transmission cars, but then they offered double-declutching as a solution. However, it is very hard to correctly judge the amount to press the gas pedal, making it very likely that you're either over-revving or under-revving the engine. Thus, there is some wear on the synchronizers unless the driver has magical ability to estimate how much to press the gas pedal. Yes, double-decluthing does save some synchronizer wear but not all synchronizer wear.

My recommendation is the following:

• Don't shift down during engine braking to avoid unnecessary transmission wear. After all, transmissions are more expensive than brake pads, discs or drums. If you need to accelerate after you have engine-braked, then do the double-declutching procedure and shift directly to the gear you want to use during acceleration.
• When shifting down due to other reasons such as needing acceleration when you have low RPMs, execute the double-declutching procedure to save the synchronizers from extra wear.
• When skip-shifting up, execute the double-declutching procedure without pressing the gas pedal to save the synchronizers from extra wear. I used to have a 1989 Opel Vectra where I skip-shifted from second to fourth without double-declutching, and I quickly learned that skip-shifting can cause noticeable synchronizer wear in less than 10 000 km. 20 year old transmission oil might have been a factor in this quick wear.
• Only when shifting one gear up you don't need to double-declutch.
• Do use engine braking as much as possible without downshifting and press the clutch only when the RPMs are slightly above the fuel injection point. The benefit is that you save some fuel and some brake wear with no extra cost.

Modern cars have the ability to do engine braking down to very low RPMs and even then you don't hear strange sounds from the engine when the RPM falls down like you used to hear on old cars. My 2011 Toyota Yaris starts fuel injection a bit above 500 RPM, and if you accidentally let the engine speed fall to the injection point, the injection at these low RPMs is smooth with no strange sounds from the engine that you could hear on older cars. So, the only effect you see is that the engine braking stops and the car continues to go forward at a constant speed.

Some answers theorized that the additional revs cause additional engine wear. Yes, they do, but only marginal additional engine wear. Maybe the engine has had 1% more revolutions if you engine brake often, but then again does that matter? It's only 1%. Besides, on a modern car, the engine is one of the last components to fail.

One answer said to keep engine revs above 1200RPM. That might be good advice for old cars, but my 2011 Toyota Yaris engine brakes smoothly down to 500 RPM.

Answer 13

Using up your clutch to slow down all the time? Replacing your clutch will cost you several hundred bucks, and unless you have a lot of special equipment, you won't be able to do it yourself.

Any time you use your transmission for accelerating, you wear down the clutch, throwout bearing, gears, synchros, and bearings. If you use the transmission to slow down, you're close to doubling the wear. Try shifting a transmission with worn or chipped gears, a toasted clutch, and worn syncros. You'll sound like it's your first time.

Transmission work doesn't come cheap. You can use your brakes all day long and the most it's going to cost you is 200 bucks for a brake job. You can do a complete brake job, front and back if you have ever handled a tool, you can do it for under a hundred bucks yourself. Keep stopping your 2,500 pound car with a clutch disc that is smaller than any one of your brake discs and start saving for that new clutch you always wanted.

Plus, try that "slow down by downshifting" trick in the rain and watch helplessly as your car swaps ends right into a wall because there's no such thing as "anti-lock clutching", and if you don't have full-time 4-wheel drive you're only slowing down with 2 wheels.

So FOR THE MOST PART... Brakes are for slowing or stopping the vehicle. Use them for that. Save the clutch for making the vehicle MOVE.

To answer the question: Does Downshifting (Engine Braking) Cause Extra Wear and Tear? Yes.

Answer 14

I would agree with the previous posters but I'd like to add that in my audi's handbook they actually advise downshifting early to save fuel.

They also make plenty of money on parts though don't they! Also from my experience their gearboxes don't last long these days at all.

Answer 15

Engine braking doesn't cause more wear on the engine if it's done properly. You should never downshift to a gear that is incorrect for the current speed. It varies significantly on each car.

If you want to save more fuel, combine coasting on neutral and engine braking when approaching each stop and anticipate in time. Release clutch smoothly when downshifting and keep calm. Keep revs over 1500 or at least above 1200rpm. (Depends on your car.) Sooner you downshift, more longer time the fuel shut off will be engaged.

Shifting to a too low gear will cause wear and damage to the gearbox and clutch. Expect gearbox and clutch failure to occur sooner. Engine braking simply doesn't mean downshifting to an incorrectly low gear so that your car jumps and screams on high revs. That's abuse.

Also remember to use the brakes hard at least once or twice a weak (when possible) because otherwise they become jammed or start dragging.

Answer 16

Ok, personally to me the best thing you can do is find out what your car idles at, downshift at the lowest rpm possible to maintain traction and engine quality. Brake when needed but try and predict when you need to have already let off the accelerator.

Answer 17

Well, if you engine braking is done in a way to causes your car to over-rev, you can look forward to picking up a rod on your passenger seat.

All the engine is doing under regular engine braking is suffering from a vacuuming effect as the pistons are moving downwards while the throttle is closed. So vacuum wants to pull the pistons up and the momentum of the car continues the rotation of the crank and fights against this vacuum.

Low compression ratio engines are marginally poorer at engine braking.