Shifting without using the clutch
 

Anyone else do this? Y'all know what I'm talking about or does anyone need a primer?

For me the higher the gear, the less often I'll use the clutch. going into 1st - almost always :D 2nd - usually, 3rd if I'm trying to accel quickly, and 4th/5th only if I'm going up a hill or in a big hurry :rolleyes:

I never use it to disengage from gear. Even when shifting quickly, my throttle lift does the trick while I'm pushing in the clutch pedal.

Now that I'm using it more both bump starting and downshifting to stay in DFCO, it's probably good that I don't...

(In my truck I'll go so far as to rev match downshift, engine brake in 1st to my 'stopping speed' ;) but it has a seriously noisy drivetrain, and in particular the clutch. I think a U-joint is in order. Before you say 'use the clutch and that won't happen' see my truck pic in the garage :p )

I'm almost embarrassed to admit it... But I just haven't been able to figure out how to do it - that is, get into gear without the clutch... I know it involves matching tranny speed to engine speed - but I'm either missing something, or just haven't figured it out yet.

But I too don't use the clutch to come out of gear :D Saves a bunch of footwork for P&G :P

That said, cartalk had a funny analogy/pun about shifting without a clutch... It's like catching a softball with your mouth - it's possible, but you're more likely to break a few teeth in the process :D

:D Nah, that's what the syncros are for. Just makes a little farting sound :D

OK. Upshifting: as the revs go down, kinda sorta push the lever into the next gear, and when the speeds match, it'll push right in. If you're close, it'll get noisy. Be ready with the clutch the first few times, and your first few tries in the higher gears and/or under low speeds/loads. If you have a tach and with some experience you can better predict when to apply pressure.

http://auto.howstuffworks.com/transmission3.htm has a really good explanation of the sync process.

This advice free with the purchase of the standard disclaimer.

Why would you bother? compare the cost of replacing the tranny to the cost of a clutch, if you get good at it, and still use the clutch then both the tranny and the clutch should last 1,000,000 miles.

Well I've been doing this since I was a teenager so it's really become a habit. I've never had either a clutch or a manual trans go out on me. (OTOH, both autos that I've owned, crapped.) So it's easier for me, one less leg to get involved. That and less clutch wear seem to be the main benefits.

Cons: slower to shift, possible trans wear that I've never seen evidence of, can be jerky. Anyone got any evidence of this?

Im sure if I tryed to do this in my car taht already has tranny issues/schro issues it could spell bad news, ive always been curious though

I've always found whether you can do this successfully (no grindy grindy) depends a lot on the individual vehicle. Some are more forgiving than others.

The ForkenSwift has no clutch, so all up/downshifts are done with revmatching & holding your tongue just right...

treb: that's an awesome Click & Clack quote. :)

Clutchless shifting in the ForkenSwift:

http://www.youtube.com/watch?v=Liqv3KgXThk

In an electric Delorean:


http://youtube.com/watch?v=mCwXfqua84k

I don't use the clutch on the motorcycle to upshift, except to get going. It is smoother that way when done right, basically a quick forward twist of the wrist to slacken the drivetrain and a lift of the toe at almost the same time, takes maybe 1/10th of a second before I'm back on the gas.

Occasionally I do it it a car, not usually though, seems to take to long and my momentum gets wasted. I know the big rig drivers dont use the clutch to shift.

I think it all depends on how many miles you expect to keep your car.

If you drive often and want longevity, I'd use the clutch all day and rev-match...little clutch wear, no synchro wear. If you drive sparingly, then saving the effort might be worthwhile...but when synchros do need to be replaced, they'll probably be expensive.

Personally, I'd use the clutch and rev-match all day, including double-clutching, but I drive sparingly and mostly freeway so it's easier to tolerate anal driving habits.

I've heard about that too, but read somewhere that it was illegal. I have no idea why, but I can understand why it's done: 18 gears and a stiff clutch pedal must suck...Clutchless shifting, dual logbooks, what other illegal things do truckers do? :p

- LostCause

I've done it.
Sometimes "just cause", sometimes because of a broken clutch . . .
Not very hard, but some skill is required.

The question is, do you think that you are saving fuel by doing it?

I try and shift fast enough so that even though I have released the throttle the engine is still spinning somewhat faster than the disk . . . I think that saves some fuel, not sure though . . . . Quicker time to speed without using more fuel for sure . . . .

Ditto. I work in the gearing industry. We go to great pains to grind gears to an incredibly high precision to provide maximum torque capacities out of these kind of things. Of course there is a saftey factor built into everything so you can get away with it. But, as Ryland said, why do it when there is a perfectly capable system already in place to do it better?

I discovered this years ago by accident, but I don't do it.

You'll burn out the syncroes. It's a lot cheaper to replace the clutch than it is to crack open the tranny and replace them.

So, will the electric DeLorean go 88 MPH? :p

I agree with the clutch issue -- use it.

RH77

I think most bikes have "dog" cut gears, and are designed to be shifted with out the clutch. Cars are designed to be shifted with the clutch and, on most vehicles, you will quickly wear the synchros out. Some makes (Hondas especially) will shift without the clutch well, but thats a rarity instead of a standard. I wouldnt do unless you are ready to rebuild a tranny soon.

Ya, but it needs 1.21 Gigawatts of power...:D

I believe all manual transmissions use dog teeth since shifting is done by engaging a gear through sliding collars splined to an input/output shaft.

All manual transmissions (that I know of) are designed to be used with a clutch. Motorcycle transmissions usually don't use synchros, so technically the driver must double clutch when deccelerating. I don't know why motorcycle transmissions are more forgiving, but since double-clutching is a pain, most just shift higher gears clutchless (which increases wear).

- LostCause

So I've figured out how to get 4th and 5th.... 4th is a slow shift - 5th is a super fast extra firm shift (the difference in rpms is 500). Can't quite figure out third - and I won't try second until I get third :p

I'm not looking to just stop using my clutch - I figure it's a good skill to know in the event a hydraulic component decides to crap out on me :p

One thing I noticed.... If I slightly miss - then hit the clutch and continue with the shift - the dogs don't mesh. They continue to interfere and I can't get into gear until I pull back near neutral and retry.

This technique is easiest to do in an older car with a sloppy, worn-out gearbox, which is precisely the type of car which is more likely to experience a clutch cable, hydraulics, or arm failure.

my trucker shifts without a clutch. I watch. non-synchronized tranny's work best for this. separates the men from the boys. :)

OK, thanks for all the info and free internet advice! :D

I agree that the clutch is a wear item and synchros aren't. I'm not recommending it as a daily practice, but it's why I can still drive my truck so it's good to know just in case. :thumbup:

This has nothing to do with FE...although everything affects FE, it would be hard to find it in a test.

Hondas do this very smoothly...if I grind it's surprising. My truck is RWD and has a long throw shifter, so it's harder. Takes longer too, prob the large flywheel. OT, the Honda is easier to bump start too. :hmm:

It's much harder in the lower gears since you want the revs to drop at a very low rate. I basically save this technique for the higher gears, when I'm at cruising speed, not accelerating.

It does save fatigue. All of the driving that I do involves nothing but accelerating and decelerating. I often don't make it into 4/5 with a more than one traffic light per mile.

OK, does anyone use the clutch to come out of gear? Coz I never do that :rolleyes:

I used to, until it killed the synchor in the Neon... With only 20,000 miles on it! Lucky me though, when the dealer tore down the transaxle (under warranty at the time!!!), the diff pin was about to slide out. One new transaxle later, and I have 50,000 miles on the replacement.

boxchain: I never use the clutch to come out of gear in the Firefly/Metro, though I always do on upshifts.