down shifting vs. netural drop use brake

[Larry0233]

i hear from different people that downshifting to stop is bad and will mess up your transmission and wear out your clutch.

yet i hear from other people that netural dropping and using your brake to stop will mess up your transmission

are either one of these true?

 

[DSMSpyder99]

you cant mess up the trans because that why they invented syncros. But you can wear out your syncros after a long time by just downshifting. THat is why I double clutch when i down shift to keep the syncros healthy. WHO EVER SAID PUTING IN NEUTRAL AND BRAKING MESS UP THE TRANS SLAP HIM That makes no sense you common sense man.

 

[Jimmy Jr.]

Screw downshifting. Between all the clutch wear, tranny grinding and syncro mashing your just better off using the brakes, and how much is a set of new pads anyway? $100? Anytime the tranny needs to be worked on it either costs you a lot of time or a lot of money.

 

[bosljeff]

Screw downshifting. Between all the clutch wear, tranny grinding and syncro mashing your just better off using the brakes, and how much is a set of new pads anyway? $100? Anytime the tranny needs to be worked on it either costs you a lot of time or a lot of money.

Amen!!! I used to downshift a lot, then after replacing my first clutch (I know downshifting isn't 100% responsible for clutch wear) I figured the same thing: brake jobs are easier than any clutch/tranny/syncro work anyday.

Drop to neutral and use the brakes. Hell, even if you hate brake jobs, go to Midas and get lifetime brakes for under $100.

Boz

 

[Defiant]

Egad, ONLY go to neutral when you're stopped. Leave it in gear, leave it engaged and use the brakes. 5th won't bog until you're down to 1200 rpm or so, and by then you're in another gear anyway.

 

[dynatos]

as stated, when you need to downshift, rev the engine to where you're shifting to. (i.e. you're at 2500 in 5th so rev in between the shift to 3500 to shift into 4th and you're doing the work of the sychro.) But even that is using the clutch - brakes are cheaper and easier to work on.

 

[ldstang50]

mer personally having a torquey motor i downshift, do the whole goose the gas to match rpms for the lower gear. but as stated its more work on the clutch and tranny. i'm not gonna say which is better or worse, thats just my personal way of driving.
when it comes to performance driving such as road racing, you better bet your downshifting.

 

[dynatos]

and it's just good practice to learn to double clutch and use that skill. If you need to get into 3rd at 68mph, do your synchros a favor and match the rpm. But for daily driving, just use your brakes more.

 

[nutshot]

Acceleration is hard on your motor, it wears the rotating parts out.

Cornering is hard on your tires, it will wear off the tread.

Climbing into and out of the car is hard on your seats, it will wear out the fabric and thigh bolsters.

Wearing shoes in your car is hard on the carpet, the rubber soles are harder than your socks.

Taking your car outside is hard on the paint, UV rays will erode and destroy it.

Putting fuel in the tank is hard on your car, the tank will become filled with harmful deposits.

Changing the oil filter on your car is hard on the block, the threads are worn each time.

Please, don't tell me that maintaining proper control of a vehicle is too high a price for wear and tear. If you don't want to downshift, sell the car to someone who will and leave the driving to us.

 

[ldstang50]

nicely said!
as far as double clutching. double clutching is an old technique used on old cars and trucks to get the gears to match up when they were UP shifting. you dont' double clutch when you down shift
double clutching goes like this. you're in 2nd gear you want to get to third. you press the clutch in pull the shifter out of 2nd and into neutral then release the clutch. the shifter still in neutral, press the clutch back in, while the clutch is in goose the gas, the press the shifter up to 3rd gear and release the clutch. double clutching is just that, pressing the clutch in twice (hence the double). you do not double clutch when you downshift

 

[DSMKevan]

Yes you do doubleclutch when downshifting.....its called rev-matching. Its basically an easier way of heel-toe downshifting. Lets say youre in 4th gear going 80mph and you want to brake and shift down to 3rd. If you dont revmatch the car will buck due to the difference in engine speed and tranny "speed". This is hard on the car. In order to prevent this, you have to double clutch, but while doing it you have to "match the revs".

Heres a guide:
http://www.nasaproracing.com/hpde/heelandtoe.html
http://www.edmunds.com/ownership/howto/articles/45792/article.html

 

[ldstang50]

Yes you do doubleclutch when downshifting.....its called rev-matching. Its basically an easier way of heel-toe downshifting. Lets say youre in 4th gear going 80mph and you want to brake and shift down to 3rd. If you dont revmatch the car will buck due to the difference in engine speed and tranny "speed". This is hard on the car. In order to prevent this, you have to double clutch, but while doing it you have to "match the revs".

Heres a guide:
http://www.nasaproracing.com/hpde/heelandtoe.html
http://www.edmunds.com/ownership/howto/articles/45792/article.html

once again NO you do not double clutch when downshifting. Double clutching=pressing the clutch in twice. If you read the guides YOU posted, it never says to release the clutch until rpms are matched. Thats one press of the pedal. You can post all you want about these little classes on line. Its too bad I DID go through Skip Barber Driving School up in Lime Rock Connecticut.
http://forum.mpt.org/messages/9/444.html?1023977576
anyone with any knowledge will tell you, you do not double clutch when downshifting. The act of downshifting is similar but it is NOT double clutching. Double clutching, I'll state this again, was primarily used in older cars and trucks that did not have synchronizers. The double clutch technique is used when upshifting. The reason for pressing in the gas is because when you press the clutch, pull the shifter into neutral, release the clutch the press it again, the rpms have dropped. You need to goose the gas to get the engine off idle speed so the gears can engage.
When downshifting, you press the clutch in and as you are pulling the shifter into the lower gear you pressing the gas. There is a SINGLE press of the clutch, the clutch remains disengaged when you are moving the shifter to a lower gear and while you goose the gas. Then you let out the clutch.
http://www.thefastandthefurious.com/
here click on the sight it'll improve your knowledge, and remember, you dont' race for money, you race for slips and respect!

 

[Defiant]

Simply wrong. A double-clutch downshift is:
Clutch in, shifter to neutral
clutch out, throttle blipped to bring gearbox up to road speed of lower gear.
Clutch in, shift to lower gear, clutch out.

It matches crankshaft, flywheel and layshaft to the roadspeed of the lower gear, and -besides obviating synchro wear- assures that the rear wheels don't break traction as the clutch is left out.

I have no idea what Skip is teaching these days, but what you described was not double-clutching.

I double-clutch every downshift, and have since my first car -a 1960 Sprite with a non-synchro first gear.

"Rev-matching" is blipping the throttle before the clutch is let out, but it doesn't do anything to bring the gearbox layshaft up to speed, and relies on the synchros to do all the work. Which is why DSM 2nd gear synchros die so often.

http://www.driversedge.com/dblcltch.htm

http://www.triumphspitfire.com/healtoe.html

 

[kpt4321]

To back up the people who are correct in this thread:

In order to rev match properly AND minimize synchro wear, you need to double clutch. End of story.

 

[deez90awd]

as ldstang50 said, you do not double clutch when you downshift. its a single press of the clutch. why you are pressing your clutch in twice in unbeknowest to me. you're simply doing it wrong and wasting time. you should not have to press in your clutch twice for downshifting, if you do, something is wrong with your tranny. you double clutch on upshifts with transmissions that do not have synchronizers.

 

[deez90awd]

This is ldstang50. I can't log in on this comp. Anyways, since we are doing the who can post more sights thread here on 'proper' double clutching, here's another. I've read it, so don't flame me for saying it goes against what I've said. I will simply say this, double clutching is meant for upshifting on trannies without synchronizers. I have never heard of double clutching for downshifting. If you all think about it, it takes too long to do so. The proper way to downshift only requires one press of the clutch not two. I have no idea where these people get these ideas. But here's the sight
http://www.urs4.com/technical/miscellaneous/Igor.html

 

[DSMKevan]

Simply wrong. A double-clutch downshift is:
Clutch in, shifter to neutral
clutch out, throttle blipped to bring gearbox up to road speed of lower gear.
Clutch in, shift to lower gear, clutch out.

It matches crankshaft, flywheel and layshaft to the roadspeed of the lower gear, and -besides obviating synchro wear- assures that the rear wheels don't break traction as the clutch is left out.

I have no idea what Skip is teaching these days, but what you described was not double-clutching.

I double-clutch every downshift, and have since my first car -a 1960 Sprite with a non-synchro first gear.

"Rev-matching" is blipping the throttle before the clutch is let out, but it doesn't do anything to bring the gearbox layshaft up to speed, and relies on the synchros to do all the work. Which is why DSM 2nd gear synchros die so often.

http://www.driversedge.com/dblcltch.htm

http://www.triumphspitfire.com/healtoe.html

Thats EXACTLY what I was trying to explain. I was wrong about the rev matching part, but the double clutch info was exactly what I meant to say. I guess I was trying to explain "double de-clutching"

 

[kpt4321]

This is ldstang50. I can't log in on this comp. Anyways, since we are doing the who can post more sights thread here on 'proper' double clutching, here's another. I've read it, so don't flame me for saying it goes against what I've said. I will simply say this, double clutching is meant for upshifting on trannies without synchronizers. I have never heard of double clutching for downshifting. If you all think about it, it takes too long to do so. The proper way to downshift only requires one press of the clutch not two. I have no idea where these people get these ideas. But here's the sight
http://www.urs4.com/technical/miscellaneous/Igor.html

So wait. You can double clutch on an upshift, but not on a downshift? It takes "too long" on the downshift, but it doesn't take too long on the upshift? Think about that terrible logic for a second.

Explain to me why you need to double clutch on an upshift, please. Oh wait, you don't. The input shaft's speed will slow down naturally, and therefore you just need to wait before you put the transmission in the next gear. You don't need to do it on an upshift.

On he other hand, on a downshift, the input shaft will begin spinning at the rate in the higher of the two gears. The input shaft is spinning at the engine speed in the higher gear, but you want to go down a gear. Going down a gear will have the end result of a faster engine speed as well as a faster input shaft speed. Without double clutching, there is no way to accelerate the input shaft up to the newer faster speed. None. Zero. The synchros will do this for you, on a transmission with them, but on a tranny without synchros, or if you want the least wear and the smoothest shift possible, you need to double clutch.

Don't come back with some stupid argument. Those are the facts, and unless you can prove one of them wrong through real world examples and facts, I don't want to hear from you again.

 

[kpt4321]

Secondly, some comments about that site that you linked to:

First of all, at the bottom of it there is an explanation of why, exactly, you need to double clutch on a downshift. Do you not understand that?

Second of all, the guy who wrote it seems to be somewhat of a moron. For example, he thinks that hitting the brakes would cause a car to lose traction, but downshifting wouldn't? There is the same goddamned traction force avaliable in both situations, so the only issue is modulation, in which case the brakes are much better. That guy is dumb.

 

[Defiant]

We're in a tailchase here, and to save the feelings of the people who are wrong, and the blood pressure of the people who aren't, I'm ending this trainwreck of incorrect posts.