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Old 04-18-2008, 02:03 AM   #1 (permalink)
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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 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

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 )

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Old 04-18-2008, 02:08 AM   #2 (permalink)
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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 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
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Old 04-18-2008, 02:23 AM   #3 (permalink)
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Nah, that's what the syncros are for. Just makes a little farting sound

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.
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Old 04-18-2008, 02:26 AM   #4 (permalink)
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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.
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Old 04-18-2008, 02:49 AM   #5 (permalink)
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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?
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Old 04-18-2008, 08:36 AM   #6 (permalink)
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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
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Old 04-18-2008, 10:35 AM   #7 (permalink)
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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:




In an electric Delorean:


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Old 04-18-2008, 10:53 AM   #8 (permalink)
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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.
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Old 04-18-2008, 04:23 PM   #9 (permalink)
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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.

Quote:
Originally Posted by dcb
I know the big rig drivers dont use the clutch to shift.
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?

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Old 04-18-2008, 04:28 PM   #10 (permalink)
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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 . . . .

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