Clutch wear prevention and technique

Hi guys,

First post

I have some quite specific questions regarding clutch wear and clutch technique.

It started off me wanting to know how fast I should press/unpress my clutch when changing gears. After reading a mass of articles on clutches i'm confused! I'm now under the impression I shouldnt use any throttle when changing gears (as revving when between open/closed clutch causes wear and referred to as riding the clutch)


I've tried changing gears this morning on the way to work without using ANY throttle and found it jerky and impossible.

The technique I normally use is *foot completely off gas - depress clutch - revs drop to 1000 - select gear - start to unpress clutch - around half way point on clutch use throttle to add revs of around 1100-2000 - unpress remaining half of the clutch - once then fully in gear add more throttle as required*


Am I causing wear by doing this?

How fast should you actually press/unpress if someone could count in seconds on a drive today would be much appriciatied - obviously 1st gear is an exception to get the car rolling - should 2nd gear upwards be a controlled 5-10 seconds press, then same on unpress, or a swift 2 second in out job?




Sorry for a complete noob post LOL


P130

Takes me about 1 second to shift from first to second and same for other gears. Anything longer is dragging. If you leave your foot on the clutch peddle while driving you are riding the clutch and it will wear faster.

You will get many different answers on how to do this.

My answer: You should press/depress the clutch in one single, fluid, motion. It should be smooth. And synchronize your shift to take place as you depress and let up on the clutch. The clutch pedal should be on the floor for only a fraction of a second, just long enough to ensure the next higher gear is selected before you let out the clutch to prevent a gear clash. (leaving the clutch pedal on the floor longer won't hurt anything, though).

Do not worry about trying to change the RPMs between shifts. When you let off the accelerator, the engine will slow naturally and if you time it correctly, will be turning at about the same speed that the transmission input shaft will be spinning in the next higher gear. This is what you are shooting for, and honestly, it just takes practice. You will get the hang of it sooner than you think.

Shift at an engine RPM that when after you shift to the next higher gear, will put the engine at near maximun torque (diesel only). That RPM in the next higher gear will be 1800 - 2200 and then ease into the accelerator after the shift (dont just stomp it). Road grade, gear the car is in and your desired acceleration speed will determine the actual shift point.

The clutches are so rhobust in these cars, they will last at least a couple hundred thousand miles, even in heavy traffic use, so do not worry about wearing out the clutch. But, the only time you should slip the clutch AT ALL is when starting out in 1st or reverse gear. If you time the shifts correctly you will not wear the clutch between shifts hardly at all, since the engine and transmission speeds will be almost identical.

--Nate

Ok, yer thinking too much here, no good can come of that, sorry it's a Law.

So here's the simple and safe technique: practice shifting as quickly as possible and as smoothly as possible. Your discovery that NO throttle during the shift was jerky is right on: don't DO that, it's also horribly wearing on the clutch plates.

Your goal should be to fill a glass with water to within 1/8th inch of the brim, set it in the cup holder, and drive around on flatland without ever spilling a drop. This will give you fabulous mileage as well as both clutch and brakes that last the lifetime of the car. Yeah, I know, this is impractical in real-world traffic, so make it a mental water glass and strive to keep it smooth.

Doing this without thinking is the goal. If you think about it too much, it will slow you down, and that is bad. All you need to do to get this right is practice quick and smooth. This is simple and it will work for you.

Know this: the wear on a clutch is directly proportional to the amount of work it does. Work is defined as the number of revolutions of slippage times the clamping force on the plates.

What this means is that for optimal (ie, low) wear rate, you need to minimize the number of revolutions that the clutch slips AND the amount of difference in speed between the two sides the clutch is attempting to equalize. (The speed difference is indicative of the forces involved.)

So, if you want to preserve your clutch, start from rest with minimal throttle and get your foot off the pedal fairly quickly. And when you shift up a gear, don't be in a big hurry to get your foot off the throttle, as you want the clutch to open without spinning and the engine revs to match the new gear when the clutch closes. When shifting DOWN, the same rule applies, recognizing that this time you want the engine revving faster than it was before when you take your foot off. This is also the prescription for both shifting without using the clutch at all and for shifting so smoothly nobody notices you've done it.

Shifting without the clutch at all is a bad idea for most folks, noobs especially, as it leads to VERY rapid loss of the synchronizers in the transmission if you are at all off on the throttle position.

Once you perfect the up shift, going to higher gears, start working on downshifting.

One source of wear that may not be evident is downshifting. Many people downshift, but have to let the clutch out slowly to match engine-transmission speed differences. ANytime you let the clutch out slowly and there is a speed difference between the trans and engine, you are unduly wearing the clutch.

I prefer to 'double clutch' on downshift. downshifting, going down one gear, (5-4, 4-3, etc.) is needed when approaching or going into corners, and in traffic, to get around some slow-poke.

Double clutch:
1) Let off the accelerator
2) Depress clutch
3) Move shifter to neutral
4) Release clutch
5) depress accelerator slightly and quickly to keep engine rpm up
6) Depress clutch
7) Move shifter to next lower gear
8) Release clutch

Ideally, there should be minimal engine rpm change from step 5 to step 8.

This all happens in ~1 second; it's really quite quick and should result in no bucking and no 'gradual' releasing of the clutch to match engine to trans speed.

After it is mastered, this keeps the engine RPM up (and rotational energy) between downshifts and reduces shock on the driveline and wear on the clutch.

Tony

Guys thanks!

Went for a drive tonight and taken everything onboard, smooth fluid clutch motion, gear change, fast out on the clutch with throttle to match and WOW! 110% better than my attempts at babying the car and changing gear so slowly and ridgidly.

I've drove manual transmission for several years but only old bangers and picked up bad clutch habits. Only got my Passat 2 weeks ago and want to drive it right from the offset

Most people don't double clutch anymore, but it helps with wear and tear on the tranny. Here's a link that may help you understand what's going on.

http://en.wikipedia.org/wiki/Double_clutch

Look up heel and toe downshifting if you want to rev match and downshift a lot. If you have small, narrow feet it might be tough on the MKIV's though.

I personally have recently begun to limit my downshifts when coming to a complete stop to save the clutch. I'll downshift from 5th to 4th but never below that when coming to a stop; it's not really worth it. Idle speed is only like 25-30 mph in 4th. I'll just put the clutch in when I get to that point and keep it in until the stop.

I prefer double clutching. One clutch 1/2 to the floor out of gear.
release 1/2 to the floor in gear. throttle to speed as you release. doing that got me to 229k miles on a 1997 toyota tercel stock clutch!

eb2143 said:

Look up heel and toe downshifting if you want to rev match and downshift a lot. If you have small, narrow feet it might be tough on the MKIV's though.

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Heel toe downshifting on these cars is impossible for practical purposes. The throttle is locked out when there is a brake switch input to the ECM. The only way to defeat it is to pess the accelerator, let off completely and then get back on it. By this time its almost always to late for the heel toe to be useful. I really wish a chip tuner would figure out how to delete this "safety" feature.

Matthew_S said:

Heel toe downshifting on these cars is impossible for practical purposes. The throttle is locked out when there is a brake switch input to the ECM. The only way to defeat it is to pess the accelerator, let off completely and then get back on it. By this time its almost always to late for the heel toe to be useful. I really wish a chip tuner would figure out how to delete this "safety" feature.

Click to expand...

Not all model years are locked out. The '96 Passat's, at least mine, are not. I've been trying to coordinate heel-toe shifting and am able to 'blip' the throttle.

Tony

Matthew_S said:

Heel toe downshifting on these cars is impossible for practical purposes. The throttle is locked out when there is a brake switch input to the ECM. The only way to defeat it is to pess the accelerator, let off completely and then get back on it. By this time its almost always to late for the heel toe to be useful. I really wish a chip tuner would figure out how to delete this "safety" feature.

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I also have no problem doing heel toe downshifting in my 02 golf. The throttle lockout is not immediate in my car for some reason (haven't driven any other tdi's before, so i can't speak for others), but in the time that the ecm takes to cuts back the rpm, I have plenty of time to match rev's.

Matthew_S said:

Heel toe downshifting on these cars is impossible for practical purposes. The throttle is locked out when there is a brake switch input to the ECM. The only way to defeat it is to pess the accelerator, let off completely and then get back on it. By this time its almost always to late for the heel toe to be useful. I really wish a chip tuner would figure out how to delete this "safety" feature.

Click to expand...

My '01 is normal, no lock out whatsoever

One good way to prevent wear is to not let anyone else drive the car, especially if they're used to gassers.

Also, don't let your significant other drive the car, because if he/she's driving and you complain about their clutch technique......

robhegedus said:

I also have no problem doing heel toe downshifting in my 02 golf. The throttle lockout is not immediate in my car for some reason (haven't driven any other tdi's before, so i can't speak for others), but in the time that the ecm takes to cuts back the rpm, I have plenty of time to match rev's.

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Every one I've driven and tried heel tow with cut the thottle between 1500 and 2000 RPM then won't rev again until you release the pedal completely or take your foot off the brake. It is possible that pre 2002 cars don't have this glorius feature and It may act different on different cars but if anyone knows how to get rid of it let me know.

Sorry for the mini hijack. As you were.

Basically.... dont slip it!

I think we should be more concerned about our syncros than our clutch... Gotta rev match especially on downshifts!

Nothing like kicking an LS1 up to 5500 rpm to drop 2nd gear at 45mph!

Not sure how to do it at all... I've been driving manuals way too long, its like asking me how I move my finger to a pointing position...I just do it. I must not be doing it wrong as I have 430,000kms on my original clutch. I do know that I don't double clutch or match revs with accelerator on downshifting.

Great advice so far thanks guys

A question on reverse gear does anyone actually bring the clutch all the way out and just reverse with *really* low throttle, or treat is the same as first gear and use biting point to brake/reverse

robhegedus said:

I also have no problem doing heel toe downshifting in my 02 golf. The throttle lockout is not immediate in my car for some reason (haven't driven any other tdi's before, so i can't speak for others), but in the time that the ecm takes to cuts back the rpm, I have plenty of time to match rev's.

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All TDIs have this feature to save of fuel while braking . When ever the brake is depressed the throttle is disabled .

On shifting smoothly , Every time you shift there are two points of "Zero Resistance" , the point when the rpms sync up with each gear and no force is being applied from the wheels or from the engine through the drivetrain . This point of No torque from the wheels or engine is the perfect point when shifting can be done without depressing the clutch .

A good way to get a feel for this is to let up on the throttle and pull the trans out of gear without depressing the clutch . Now once you get this down you can wait for the rpms to sync up with the next gear ratio and it will slide into that gear with little if any effort . With practice all the gears can be shifted without depressing the clutch . And even if you don't use the shift without the clutch this knowledge can make for better smoother lower resistance shift reducing clutch wear .

When shifting without the clutch 1st to 2nd are the easiest because of bigger difference in ratios . 4th to 5th are the hardest due to closeness of ratios . 2nd to 3rd the next easiest with 3rd to 5th is a little easier than 3rd to 4th or 4th to 5th .

You move the throttle up & down shift gears just as before timing each shifting perfectly at the two points of "Zero Resistance" only difference is you don't depress the clutch . With practice this can be done without thinking about it , I've been doing this for close to 35 years in all types of vehicles from 18 wheelers to motorcycles . Many call this form of shifting "speed shifting" for it's exact timing at a precise speed of shifting .

On reversing? Depends how far/fast you're needing to go.

If in doubt, remember this: a slipping clutch is wearing.

Minimize clutch wear? Learn to shift without the clutch on all but start from stops.

Accelerate to desired shift speed, go to minimum power/throttle and bump into neutral. If power/throttle is properly minimized then there will be little reistance into neutral. Blip throttle to match speed and revs for next gear to save the synchros and smartly snap the lever to the next gear and get on it.

So save a ~$400 part and wind up with a $1500+ transmission rebuild instead when the syncros and detents are shot.

VFchicago88 said:

I think we should be more concerned about our syncros than our clutch... Gotta rev match especially on downshifts!

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Someone correct me if I'm wrong, but isn't it true that rev matching won't do anything to prevent synchro wear if you're not also double-clutching.

You really don't have time to double clutch when rev matching. Double clutching is depressing the clutch, into neutral, clutch out, depressing the clutch again, then into gear. Rev matching typically means no clutch use at all. Though I like to rev match and use the clutch.

CopaceticMind said:

Someone correct me if I'm wrong, but isn't it true that rev matching won't do anything to prevent synchro wear if you're not also double-clutching.

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The only thing double clutching does on modern transmissions is double moving parts wear.

It helps if you are a poor rev-matcher or need it to help time your shifts. It won't increase or decrease synchro wear on its own, however.

...of course, if you need to slam into gears then you must double clutch...

I drove my mkiv Jetta with a failed pressure plate for 30 miles and had to rpm match my shifts, and these cars don't like it. All the Hondas, Mazdas and Subarus I've owned did this trick without complaint, but the vw likes you to use the clutch for up shifting.

Also, double clutching will wear out your throw our bearing at double the rate. So, basically something has to wear out, I vote clutch plate because they last a really long time.

My advice is smooth shifts with little slipping up shifting, down shifting holding in the clutch and blip the throttle to get rpms close to where they are going to be when you let the clutch out. Don't bother down shifting past third unless there is a crazy downhill. Brake pads are cheap.

The faster you accelerate the faster the clutch wear too.

If you're looking at fuel economy and longevity of parts, clutch wear due to downshifting can actually pay for itself so long as you realize that you want to release the clutch quickly as to reduce the heat input.

Using the engine to control speed versus the wear parts (brakes, clutch).

This also decreases the fuel being injected with fuel shutoff above 2000 rpm

Not jamming it into gear and not using the clutch for heavy, or super heavy, acceleration are inmo the best ways to preserve the components involved.

Clutch and brake pads are made in the same manner, just different shapes and functions.

Fancy clutch plates have springs to moderate the forces applied to the plate and reduce the risk of the center snapping under heavy acceleration.

High friction clutches tend to employ higher pressure "pressure plates" to limit slipping and improve greater acceleration capabilities (mainly recommended for tuned vehicles over powered for stock clutches).
I also recommend higher grade clutches for stock vehicles as it is capable of more and will last longer overall.

My $0.05 worth of free advice. I've driven manual trannies all my life and never worn out a clutch. Current record is 305K miles on my '02, OEM clutch. I agree with pretty much all what's been said so far. Double clutching, however, is unnecessary on a synchronized gearbox. This is a holdover from the old "crashbox" transmissions, but also still 100% necessary on transmissions in big trucks as they are all non-synchronized. These do take well to non-clutch shifting and rev-matching (just watch Youtube), but they have almost nothing in common with our little boxes aside from gears and oil.

Downshifting on our cars is pretty useless. Save the clutch and use the brakes. Maybe if we had an exhaust brake or a little set of Jakes....LOL

The biggest "feature" I love about the TDI is the ability to get away from a stop with NO throttle at all. Just let the clutch out to the engagement point, hold it until the car and engine catch up and then let it out the rest of the way. I can even pull my little fishing boat (14' aluminum with 25 hp motor) up the ramp with no throttle at all. Just a very small bit of clutch slipping. Granted, it's a rather modern ramp and quite a shallow slope, but still, it's sooo easy with the TDI!

Chris

Chris B said:

My $0.05 worth of free advice. I've driven manual trannies all my life and never worn out a clutch. Current record is 305K miles on my '02, OEM clutch. I agree with pretty much all what's been said so far. Double clutching, however, is unnecessary on a synchronized gearbox. This is a holdover from the old "crashbox" transmissions, but also still 100% necessary on transmissions in big trucks as they are all non-synchronized. These do take well to non-clutch shifting and rev-matching (just watch Youtube), but they have almost nothing in common with our little boxes aside from gears and oil.

Downshifting on our cars is pretty useless. Save the clutch and use the brakes. Maybe if we had an exhaust brake or a little set of Jakes....LOL

The biggest "feature" I love about the TDI is the ability to get away from a stop with NO throttle at all. Just let the clutch out to the engagement point, hold it until the car and engine catch up and then let it out the rest of the way. I can even pull my little fishing boat (14' aluminum with 25 hp motor) up the ramp with no throttle at all. Just a very small bit of clutch slipping. Granted, it's a rather modern ramp and quite a shallow slope, but still, it's sooo easy with the TDI!

Chris

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The only thing I would add to that is torque matching is essential also to reduce clutch throwout bearing wear. What that means is when the engine throttle settings and the torque coming from the wheels match, you can pull the transmission out of gear without engaging the clutch when coming up to a stop.

The other thing is it's a little harder to take off without throttle input on the TDI's from the PD engine forward, but it still can be done because I have done it many times .

And The current cr engines also are throttled down to the point with a similar raised up minimum speed kill rpm so low that they can be only be one taken off with extra care without extra throttle input from a stop.