Is it better to brake only or down shift and brake on a manual transmission? I have always had this question on my mind for years.

I have always heard
 

it is better to brake because brake parts are cheaper than tranny/drivetrain parts.
Jim
'85 300D
'95 E320
'97 CRV

Thanks Jim. About how much would it decrease the manual life?

Tut, Tut, Gentlemen...
 

The reason you have gears to shift in the first place is to maintain the proper RPM for optimum performance of your engine. That applies to acceleration as well as braking.

I always downshift prior to applying the brakes. You will be able to maintain better control of your vehicle, and you will be in a better position to accelarate sooner if and when the situation calls for it. The only exception to this, is if some bonehead does something that forces me to brake first, and then pick the correct gear.

There is nothing wrong with correctly downshifting to aid in braking, or even in lieu of braking, if you do it correctly. This applies to manual as well as automatic transmissions. And there should be no excessive wear caused by correctly downshifting your car. The key is doing it smoothly, and being aware of what gear you should be in at a given speed, and them matching the RPM to those two factors. Speed+RPM+correct gear.

Next time you drive your car, make note of the RPM range you run in before shifting. What is the high RPM when you shift, and what is the low RPM after you shift (when you let out the clutch)? Then, keep track of your speed range in all of the gears (this is easier if you have someone write it all down while you are driving), For instance, 1st gear, 0 to 15 MPH, 2nd gear, 15 to 30 MPH, etc. So if you know, for instance that you are going 25 MPH in 2nd gear at 3,000 RPM, you will know that if you want to shift down to 2nd from 3rd, that you need to do so when you are going 25 MPH, and will need to increase your RPM to 3,000 in order to do a smooth shift. Then, after you do that, you can decrease throttle pressure to slow down smoothly.;) Just remember this: Whatever speed you are going when you shift into a higher gear, is just a different RPM for either gear. 25 MPH in 2nd = 3,000 RPM; 25 MPH in 3rd = 1,200 RPM, get it?

Again, the purpose of shifting is to keep your engine operating in the optimim power curve for the drive train on your car. I hope you follow what it is I am saying, and understand that all of the numbers I am using here are simply hypothetical examples and not absolute guidelines of any sort. :D

This stuff takes time and practice to get it right, and high performance driving schools actually charge you money to learn how to do this correctly.



[Edited by longston on 03-03-2001 at 07:32 PM]

While I hate to disagree with Scott, I do :D
High Performance driving schools (at least none that I have been to) do not teach to down shift before braking, EVER.
Say you are going 140+ MPH at the end of a straight with a 180 degree curve ahead. You brake before you enter the turn to scrub off speed and shift the weight of the car from rear to front to help steering. When you enter the turn, you use the heel-toe technique (gas & brakes at same time) while you down shift into the appropriate gear. In some situations (never high speed) you could slow the car down by down shifting but you risk the possibility of over-revving the engine and it also throws the car off balance. Not to mention that brakes are MUCH less expensive than a clutch. There is a web site that details HP driving techniques ( I can't seem to find it now), I'll hook you up with the link.

Gary

Its not a either/or thing.......you need to do both at the same time!!!

Yes, And No...
 

OK, fine, you're right, and you're wrong. I'm sorry if I wasn't clear enough, or didn't explain myself sufficiently, but now I'm paying for it aren't I?:rolleyes:

In high performance driving, what Gary is correcting me on is absolutely true. But, what I was talking about was simply the proper technique for downshifting so you don't damage your clutch, drivetrain, or over rev the engine, and can still use the drivetrain and engine to aide in braking.:cool:

The answer I gave was for well thought out safe street and highway driving, not high performance "going 140+ MPH at the end of a straight with a 180 degree curve ahead." And while I understand your example Gary, I gotta ask, what, you were never taught in any instance to downshift strictly for power without braking first? :confused:

And I wasn't saying that high performance driving schools teach people to downshift before braking, I only said that was what I do, and I only meant under normal driving conditions, not while racing. What I was talking about the schools charging you money for was to learn how to shift a transmission the way I was explaining.

When I down shift, I do so in such a way as to not create an immediate braking effect, but to stay within the operating parameters of the vehicle I'm driving (at least I thought I explained it that way). But then, all of my training and experience is being focused right now on defensive driving on normal streets and highways because that't where we drive. That doesn't mean that I don't know how to, or can't heel and toe, drive by the seat of my pants, and power in and out of curves like a champ. :p

The original question from Chicagoland was phrased in such a way that I assumed that this was someone fairly inexperienced with shifting manual transmissions. Let's look at it again: "Is it better to brake only or down shift and brake on a manual transmission?" I don't think he wast asking for high performance racing tips, just about shifting and braking while engaged in common sense driving...;) Maybe I over-answered the question? Perhaps I should have just said, "downshift and brake is better", and left it at that.

But I have to disagree with this concept of driving that says that brake parts are cheaper than drivetrain parts. Initially, yes, but cumulatively, no. How many brakes and rotors does it take to equal a clutch job? And why does it even have to been seen as an either or situation? Why not get the best longevity out of both systems by using them properly? I'd wager that the way I drive, I can make my brake parts last considerably longer than most people without damaging, or even prematurely wearing any driveline components.:D

I prefer to just use the brakes to slow down rather than downshifting. The brakes are cheaper than the clutch.

My dad bought my car brand new and I inherited it. It has 200,000 miles all on the original clutch with no of slippage at all.

My clutch on my 85 Mustage GT is original 179000 miles. I prefer not to downshift to not place addition stess on the crankshaft, driveshaft and U joints.

Longston is quite correct.

Chicagoland,

Don't be limited to either braking or downshifting. You can do both at once. Matter of fact, you can brake, shift gears, AND stand on the gas... all at the same time! :)

*vroom* *vroom*

Kuan

Several questions have always been unanswered in the back of my mind and they seem to apply to this thread so I'll ask.

#1 Does downshifting manually in a Auto transmission do any harm or create any out of the ordinary wear? This is assuming you are not overrevving the motor upon downshifting.

#2 Is is OK to use the heel and toe method in a Auto by blipping the throttle to get a matching rpm just before the transmission responds with the downshift?

#3 And lastly, in a manual transmission is there any harm in upshifting to a random higher gear, such as from 2nd to 4th?

I do practice these techniques all the time I must tell you, every women who has been in the car (and some men) seem to think these are harmful? I have not seen evidence to support either side?

Ah, The Old Skip Shift, Eh?
 

First, your clutch and driveline components wear out from IMPROPER shifting and clutching, not just from downshifting, that is, assuming that the shifting is being done c o r r e c t l y....

But everyone drives differently and continues to drive the way that they have "adapted" for themselves, unless they are taught to drive by a professional instructor. BTW, The hardest part of that learning process for both the student and teacher is the first stage where the student must un-learn all of their old bad habits.

Ross, you either need to learn to drive better, or to not let stupid people ride in your car anymore!:D

Seriously, as I already wrote in this thread, manually shifting an automatic transmission is pretty much the same as doing it with a manual transmission. Read my original comments on this thread, but record the speeds and RPM' while allowing the transmission to operate in fully automatic mode. Then you will know what the normal operating range is for each position on your automatic transmission selector. So, just stay within those operating ranges for those gears, and you will not harm, or prematurely wear out anything other than the patience of those less enlightened than you.

Now as for your last question, I haven't seen anyone do this in a car in years. We used to call it "skip shifting". You mainly see it done in big trucks with more than 5 selectable gears when the truck is driven unloaded, and on a flat stretch of road. Still, you must stay within the operating range of the engine. If you, in your Mercedes, shift from 2nd to 4th, you are probably not operating the engine and driveline within the correct operating range, are likely to be "lugging" the engine, and if you have any load (slight grade for instance) on the engine, using heavy throttle will cause undue wear. However, that said, if you're entering traffic on a downhill grade, like a velocity ramp, and you don't push the car past the correct operating range, gradual accelleration will get you going faster than hitting 3rd first, and under those circumstances, will not do any harm.

See, what you're doing when you skip-shift is just creating a kind of "false overdrive" where the smallest amount of RPM can be translated into a faster speed, because you're "overdriving" the engine / transmission relationship. Older cars used to sometimes have overdrive transmissions to help save fuel. Once you shifted to the highest gear, you'd activate the overdrive which would let you cruise at high speed, but also at a lower RPM. It was like having a 5th gear.:cool:

Rule of thumb, if it feels right and smooth, it probabaly is. If it feels like you're lugging it, if the vehicle is bucking, if the tires screech, or if the car feels like to just ran into the world's largest block of gelatin, that's bad. Go to a library and see if you can check out a couple of books on driving by Bob Bondurant. He's the guy who encouraged me to shift automatics just like manuals...;)

Oh, and tell your passengers to: "Get in, Sit down, Buckle up, Shut your yap, and Hold on". :p

In regards to the "skip-shifting", this is in a manual tranny car.

My dad always used to do it and that of course brought on the comments from my Mom, "Oh Roger, stop doing that! You are ruining the car." Well he never paid much attention to the advise and now I do the same thing.

I ask because I usually do this in our Toyota Tacoma at stop lights, 1st, 2nd to the speed I want then 4th to level the speed off quickly.

As for the automatic transmission downshifting, I am mainly addressing a situation where you may be cruising at a steady speed (60 mph) and then may have the need to downshift for a little passing, its faster to already be in the gear than to wait for the auto-kickdown from the transmission.

I have always let the engine so some of the breaking on down grades and even when coming to a stop (good practice of Heel-and-Toe technique even to first gear) so I want to avoid any potential long term damage, hence my questions.

There's performance driving and there is economy driving. If you are driving for economy, you will be able to stop much, much cheaper with the brakes.

If you're talking about performance driving, I'll let the Michael Shumacher's(sp?) on this site argue that point.

Have a great day,

downshifting without matching revs also contributes to gear synchronizer wear. And if you force it, not only will the driveline be subjected to shock, but you will also upset the car's balance because of the sudden engine-braking.

once you have downshifted and are engine-braking, you are also wearing off the opposite faces of your gear teeth, especially the rear axle hypoid gear. Of course these could be negligible, but contribute to additional wear nonetheless.

but when i downshift from 5th to 4th to 3rd on an offramp (with proper rev-matching of course), i tend to forget that because of the glorious sound that inline6 makes when engine-braking in 3rd at about 4000rpm.

rev-matching is especially needed for the benz because of the wide spacing between ratios, and the high rotational mass of the engine/flywheel.

My vote
 

Having changed clutches and brakes, my vote goes to using brakes. Last clutch I changed lasted 220,000 miles and took three days to do. I could change lots of brakes in three days.

Using both the engine and the brakes to stop is like stopping a motorcycle where you have seperate controls for the front and back brakes, and you can still downshift.

blackmercedes,

Since I'm the only Larry that posted before you, I'm doing my best to see where I indicated anything about staying in fifth gear while braking. I simply indicated that it's more economical to stop the car with the brakes than with engine compression.

I'm not a clutch rider by any stretch of the imagination. If I am slowing to a complete stop and know that I'm going to slow to a complete stop, I kick it in neutral and stop the car. When I'm sitting at a light, I sit with gearbox in neutral until the light turns green then slip it in first and go. I'm partial to the throwout bearing, it's as much trouble to replace the throwout bearing as it is to replace the clutch or transmission.

I've never had a manual transmission failure of any kind with this procedure.

Just as I guessed, there are many ways to "skin a cat" and the same applies to this Topic, sorry cat owners.

Even if there was a significant amount of wear involved I would still heel-&-toe regardless. Its part of the whole driving experience to me that is satisfying. I am not hard on my clutches as the last one that was replaced was on my Integra GS-R. I drove that car very hard through every gear change, when the clutch was replaced the mechanic said that the surface was in excellent shape. In fact he asked if I was a "gentle" driver as the surface had a lot of life left in it, the reason for the replacement was because of the a bad bearing BTW.

I was always taught through reading and my Father that it is safer to always be in a gear when moving, for instance if you are braking and coasting out of gear at the same time and then a hazardous situation suddenly appears, you no longer have the instant "power on" option without selecting the gear with a shift change.

I think Jackie Steward also advocates always being in gear before entering any corner, otherwise you will disturb the suspension with a gear selection, I imagine this to be more important at race speeds as you are at the limit already.

Of course, every Heel-&-Toe shift I am referring to also means proper rpm matching, otherwise its not Heel-&-Toe to me, its just plain sloppy.

Sounds like the manual transmission might as well be from another planet in the US. As previously noted, there are many ways to skin a cat. High performance or advanced drivers will always use a manual gearbox in a different fashion to the ordinary driver. It is for the former that the heel and toe technique will be important. If you are the latter type of driver, you just won't be interested.

The simple driver is advised to use his brakes to slow down the vehicle to the desired speed, prior to engaging the correct lower gear for his new, reduced, road speed. There are many flaws in this approach, but it is appropriate for a simple driver. It does not matter whether that involves going from 5th to 2nd without stopping at gears in between, so long as gear ration is matched to road speed.

The advanced driver, as he reduces his speed using the brakes, will shift down through the box. This involves the heal and toe technique. With the clutch in, heal of right foot on brake pedal, toe on accelerator (or is it the other way round?), he blips the throttle to bring the engine speed up, while maintaining constant brake pedal pressure. As the clutch comes out, the engine speed should be perfectly matched to brake speed to avoid any sudden change in the balance of the car caused by engine compression. Of course, engine compression contributes to the decelerative effort, but this method ensures that it does so smoothly, without stress on the components, and also ensures that the driver is always in the correct gear for his road speed in the event that he needs to pick up again. Many drivers also prefer to have the engine engaged with the driveline as this enhances both their feeling of control and their actual control of the vehicle. Heal and toe is very difficult and should be practised either on a private road or where you are sure there are no following drivers. I'd be interested to know who can do it; I can't; also a lot of cars do not have their pedals arranged very conducively; the old floor hinged 911 pedals were ideal as are the pedals in a manual BMW.

It has been suggested that a driver may choose to slow the car using only engine braking. This is dangerous as following traffic is given no indication that he is braking. Use of the brake pedal lights the brake lights, obviously; crashing down the gears does not.

There is absolutely nothing wrong with skipping gears on the way up or down the box. The important thing is to be in the correct gear for your road speed and intentions. By way of example, when joining a major road with fast moving traffic from a standstill, a driver may use maximum acceleration in first, second and third gears in order to reach the speed of the traffic as quickly and safely as possible. Having reached that speed, it is entirely appropriate to slot the car from third to fifth or sixth (if your vehicle is so equipped): he has got to the speed he wants to cruise at, so there is no need for intermediate gears. This can be a smooth and efficient way of driving.

Using engine braking to slow the car doubles the number of times the throwout bearing has to carry a load, and it also places a heavy opposing load on the drivetrain parts. Lots of automatics do a good job of using engine braking, but they don't do it with the severity of the average manual transmission user who is practicing downshifting for engine braking.

Another thing I would like to point out while speaking of clutch wear is about sitting at a traffic light. Some people will sit at the light with their foot on the clutch for the entire cycle of the light. This will significantly reduce the life of your throwout bearing.

Blackmercedes,
Love that "Baby Benz" !!

95 R129
98 W163

And then there's people who sit at red lights on a hill and hold the car with the clutch.

What about shifting without a clutch? I rarely use it on my motorcycle, seldom on an old VW bug I had, and too frequently have to on my Peugeot cause the hydrolic clutch is acting up, although matching engine speed with that diesel is real easy. I've only tryed putting it in gear once with my 190, although I frequently take it out of gear without the clutch.

Ahh clutchless shifting.

I've done it, but I'm not perfect at it, and I don't have a manual car anymore, so I can't practice it. and even if I did I would not do it more than a few times if that.

But My dad is a pro at it. and can shift smoothly thourghout the gears.

We used to go racing around in a 68 vette he had, using the clutch only for first gear. Though that car did not have a hydraulic clutch either. But the hurst shifter on it was very solid and shifted clean.

Alon

I'm amazed that there are so many people on this forum that are old enough that they developed their manual transmission techniques in a car with a sliding gear transmission.

Have a great day,

Since the talk is about clutches I have a little story to tell. One time after putting an engine in a P-car we decided to go test drive the thing. The boss said okay let's go, so we went. The thing all of a sudden died on us so we of course check everything and stand around on the side of highway 118 scratching our heads looking real stupid. All of a sudden my boss asks, "did you put gas in the thing?" I'm like.. uh, uh... well errr no! After getting dopeslapped Italian style we get in the car, put it in first gear, crank the starter, and roll down the highway and UP onto the onramp to the light. It was all downhill to the gas station. That was about as close to an electric vehicle as I've ever been! This is one good use for a clutch!

Kuan

Clutchless shifting... it's easy enough going up the box, but coming down is another matter altogether!!

Wow! Thanks for the many replies!

Chicagoland