'..clutch in...' Thats completely illogical!!!

Factual Questions
1

OK I just got into a hideous arguement with Mrs.Phlosphr about her clutch burning out and the reason it did so. Please time honored friends help me prove my point, or prove me a complete ass. Is it better to leave the clutch in or out whilst sitting idle at a stop sign or in traffic etc…etc…???

I have driven my GM standard shift car for 4 years and never, ever, had a problem with the clutch!!! Mrs.Phlosphr has driven her three year old GM car and has already had to have the clutch changed because she burned it out.

I have driven with her obviously many many times and she does not really ride the clutch (well ok yes she does) but come now, she also always keeps the car in gear with the clutch in whilst stopped!! I never do this, and I have never smelled a clutch before… please let me know what that keeping the clutch in is a bad thing when sitting idle…Even if my particular point is wrong I’d like to know whats up and why…

2

It doesn’t matter, unless the clutch does not completely disengage while all the way to the floor. If it a hydraulic clutch, she is probably low on fluid (if the clutch is not disengaging completely). My guess, she’s not putting it all the way to the floor when she’s stopped. Either that, or she just rides the clutch too much.

Bottom line is:
If the car is in good working order, it shouldn’t matter. If the car is not in good working order and the clutch is not disengaging all the way, then your way is better. Although if that is the case, it would probably be causing excess wear on the transmission when shifting.

3

Leaving the clutch pedal pressed down at a stop puts extra wear on the pressure plate and throw-out bearing, not the clutch disc. Niether the disc nor the transmission is adversely affected by doing this. And try as you might, there is no way you’d ever wear out a pressure plate from doing this (though you could possible prematurely wear out the TO bearing).

Riding the clutch however, is a sure fire way to wear out the clutch disc prematurely.

4

I still remember from my driver’s ed class nearly 25 years ago, “NEVER sit at a stop light in neutral. If there’s an emergency, you don’t want to have to take additional steps to MOVE when you need to.”

I put 150K on my Chevy Nova 5-speed, always had the clutch in and the gear in first at all but really long stops, and never burned out the clutch. I also downshift to slow down.

If the clutch is burning out, it’s for some other reason. Most likely she’s a lousy shifter, or it’s a lousy transmission.

5

I am here to dispute all of the above. This is what is taught at the Bob Bondurant School of High Performance Driving. While sitting for more that 10 to 15 seconds, place the vehicle in neutral and release the clutch. Keep the brake applied fully. Keeping the clutch pedal depressed significantly reduces the life of the pressure plate and throw out bearing. This can also lead to premature clutch failure and excessive wear. A weakened pressure plate allows more clutch slippage because the tension between the pressure plate and flywheel is lessened. Driving at slow speeds in heavy traffic, ie, stop and go traffic, is the only thing worse on a clutch.

And the claim that keeping the car in gear in case of an emergency has no merit. How often does one have to suddenly get out of the way when sitting in traffic. Almost everyone stops too close to the car in front of them and would be unable to perform an emergency manuver anyway. If your vehicle is struck while engaged in gear and your foot is knocked off the clutch pedal, away you go. If the collision was to incompacitate you, your car could move on its own causing other potential injury or property damage.

6

Another thing that kills clutches is a leaking rear main seal. Put a little oil on an object that depends on friction to do its job, it will shorten the life concederably. Step up and do a compleate replacement job. Disc, preassure plate, throw-out bearing. pilot bearing, re-face the flywheel.

7

Overall, Philosphr, you are not seeing the forest for the trees. The key to this lies (basically) entirely in your wife riding the clutch. That is what is wearing out the clutch. The clutch in/clutch out at lights thing is an irrelevancy, largely, unless she is only putting the clutch out part way, which is unlikely. The only difference it makes is to marginal wear rates on components that aren’t going to wear out until well after the friction plate does anyway.

8

In the auto repair field, I’ve not heard the case made that keeping the pedal down at stops will weaken the pressure plate, though it does sound plausible. Regardless, this habit will definitely subject the release (throw-out) bearing to a lot more use and wear than is necessary. And that in itself can lead to a premature need for a repair, which will almost always be a complete clutch job (because it’s usually false economy to only do part of it).

But whether it’s from riding the clutch (a little is FAR too much), keeping the pedal down at stops, or releasing the pedal too slowly (allowing slippage), wearing a clutch out in three years is a remarkable feat. In my experience, clutches in modern vehicles typically last about 140,000 miles. I’m thinking, this car has what, less than 50K on the clock? The inescapable conclusion–that clutch has been badly misused. Somebody needs to change her ways.

9

I know the trick of putting the car in neutral, releasing the clutch and applying the brake. I do that usually when slowing down at stoplights, etc.

But what does “riding the clutch” mean? I’ve heard it before, but never really understood what it meant. Maybe I’m doing it and just don’t know.

10

Riding the clutch is basically keeping your foot on the clutch pedal while your not shifting. It engages the clutch ever so slightly and causes lots of wear. Others may come in with a different definintion, of course…

BTW, I would not recommend the slowing down technique you described, though I do occasionally myself. I believe it is preferred to downshift while you slow down, even if you keep the clutch down. That is so you can have the car in an appropriate gear if you need to maneuver.

11

Okay, here is how both my father and I drive standard cars. My father got 315,000 miles (yes, really!) out of the first clutch on his Accord.

It’s always nice to your passengers to try to be a smooth, easy driver. But with a standard, don’t ride the clutch on accelleration to be smooth; just get the car going. Usually, just about as soon as the car starts to roll at all, you can release the clutch all the way and the car will still drive smoothly.

Downshifting to come to a stop saves wear on your brake pads, at the expense of your clutch. That is stupid. On my '92 Firebird Formula, brake pads at Pep Boys range from under $20 to a high of $46, and I replace them myself in about 45 minutes, with maybe $30 worth of tools (not including jack and stands). A clutch replacement costs $400 (on an easy car, at a cheap shop), and often a lot more. And most people can’t replace their own clutch.

I also read somewhere that to just throw it in neutral and cruise to a stop isn’t good either, but I don’t know why.

Let’s say you’re driving along in fourth gear at about 45mph, and you want to stop. Let’s also say that your car idles at 700RPM. Leave the car in fourth, release the gas, and use your brakes to stop. When the tachometer goes down to about 800-900 RPM, release clutch; continue to stop. Once you’re stopped, shift to neutral, release clutch. When you see the light on the other side of the intersection turn yellow, shift back into first and get ready to go.

There’s also another cool thing you can do; I forget the name of it.

Let’s say you’re driving at 45mph in fourth gear, and your tachometer shows 1800RPM. You see a hill coming up, so you downshift to third, causing the engine to immediately speed up to, say, 2300 RPM. Everyone with me so far?

Next time, do it this way: Release gas, release clutch, move lever to third. Step on gas to rev engine to 2300 RPM, then smoothly but quickly release clutch. Of course, you’ll never get it absolutely perfect; the idea is to just be close. Now, there will only be like 50-100 RPM of difference for the clutch to have to deal with, rather than the usual 500.

And of course, she shouldn’t be riding the clutch. She my not know that the car has a dead pedal for her left foot; teach her that it is useful and comfortable.

Also, a good standard-shift driver will always be observing traffic patterns ahead: If you see a red light ahead, don’t just fly up to it and stop. Rather, slow down, but not so slow you have to downshift—possibly, the light will turn green again before you reach it, and that’s another shift you’ve just saved.

12

Actually, I’ve seen a lot of drivers wear out clutches because they were too abrubt. Relatively high-powered cars can burn clutches really fast if you just let them pop after changing gears. I guess the moral is: find the right amount of clutch for your car. My car has a tiny 1400 cc engine, so I tend to use a tad more clutch to get it going, and to get smooth pickups after gear changes. I’m sure I can be easier on the clutch, but it’ll be at the expense of my comfort, and that’s more important to me. Also, because of its low torque, my car needs more revs to get off the line smoothly than, say, a 3 liter BMW with twice the torque.

Chris: I think the reason to always keep a car in gear even when slowing down is a safety one: a car with no drive on the wheels is going to be harder to control in an avasive manoeuver.

13

Sounds like “double clutching”; but I haven’t had coffee yet. I used to have to double-clutch to shift from second to first in my old 1966 MGB. This being a pre-caffeine post, I’ll have to think about how I did it. It wasn’t something I thought about at the time – I just did it.

14

no, the maneuver he is talking bout is rev-matching:
clutch in, downshift, blip throttle, clutch out

double clutching involves an intermediate clutch release in neutral and a blip there to match the speed in an intermediate drivetrain part that would be missed by simple rev matching… i forget which one, but racer72 could probably tell you:

only race cars and people obsessed with race cars use double clutch because modern cars don’t have the straight cut gears anymore and have synchros to take care of most of the rev matching.

15

I think what Chris is getting at is, instead of having the clutch/transmission change your RPM from 700 to 2,300 when downshifting, use the accelerator to get the RPM close, to save wear and tear on the clutch.

Double clutching is clutching once to get out of a gear, and clutching again to get into the next gear. I think that is often necessary for unsychronized gears, your MGB’s 1st may have been unsynched. I’m stretching the extent knowledge here, so I may be wrong.

16

Well folks Mrs.Phlosphr has infact burned her clutch out, she insists she is a good driver “yeah yeah I’m a good driver” she says. I thought it completely crazy to burn a clutch in 90k miles…she uses her car for work and basically she rides the clutch day in and day out… she ‘thinks’ she’s drivnig well all smooth like, when in fact she is riding the clutch all the time…(you should smell our garage now) Anyway…I think a weekend lesson with her new clutch is in order. There is a very steep hill close to oiur house that we can prasctice on. But I think the overall picture on what to do when stopped is to have the clutch out in neutral…right? Thats how I always do it… thanks all…

17

Once per lifetime is often enough.

18

I think the conscencus is that the neutral thing at stoplights is a lot more irrelevant than clutch riding. I wouldn’t worry too much about it, and focus her re-education on keeping her damn left foot off the pedals whilst driving. :wink:

19

related thread: While stopped: clutch in, or clutch out?

20

kryptonite2: Yeah, that sounds more like what I did in the MG. I put in the clutch and shifted into neutral, then blipped the throttle, put in the clutch, and shifted into first. I don’t know if the 1966 MGB had synchro between second and first, or if it was just worn out. The 1977 MGBs didn’t need to be double clutched when shifting from second to first. (MGBs are fun cars, BTW. Usually two of mine were running.)