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This may be a dumb question, but I gotta ask. What is double shifting?
I remember seeing in the forum a few times, and even on F&F (even though that doesn't mean much).
 

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Double-clutching?
-Shifty
 

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its double clutching, and thats when you clutch in, shift out of gear to netural, clutch out, clutch in then shift to the next gear. Its really nice on the syncros. You used to have to shift transmissions this way, waaaaaay back in the day
 

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Double clutching is used to match the speed of the primary and secondary shafts in the transmission. Its used mainly for when coming into a corner and slowing down, so that when you downshift it doesn't upset the handling of the car (which can cause a spin) .
 

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You're confusing double-clutching with rev-matching. The former is done if your transmission has no synchromesh (eg big trucks, but this used to apply to cars decades ago), while the latter is used mostly by racers to prevent unbalancing the car on downshifts. They're very different techniques for very different purposes. :)
 

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I used to drive a 60's vintage troop bus in the military for awhile back in the 70's. I had to double clutch with every shift. No synchros - sometimes you could strongarm it into the next gear if you got the engine rpms just right while the shifter is between gears.
 

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i thought double clutching was when you were in a gear and then in the middle of the gear you engage the clutch for a second to let the engine rev higher and then pop the clutch back in.
 

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Norbie said:
You're confusing double-clutching with rev-matching. They're very different techniques for very different purposes. :)

You have to rev match to double clutch. You don't have to double clutch to rev match. And while rev matching doesn't upset the balance of the car, it still isn't as nice to your transmission. Many people still double clutch newer cars just to keep the synchromesh nice. Quite frequently I hear people complain of their cars grinding when shifting into second -- or that they can't go into first gear unless they come to a complete stop. If they (or the previous owners) had double-clutched, the transmission would behave like new even with 200,000 miles on it.
 

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ma71supraturbo said:
Norbie said:
You're confusing double-clutching with rev-matching. They're very different techniques for very different purposes. :)

You have to rev match to double clutch. You don't have to double clutch to rev match. And while rev matching doesn't upset the balance of the car, it still isn't as nice to your transmission. Many people still double clutch newer cars just to keep the synchromesh nice. Quite frequently I hear people complain of their cars grinding when shifting into second -- or that they can't go into first gear unless they come to a complete stop. If they (or the previous owners) had double-clutched, the transmission would behave like new even with 200,000 miles on it.
You don't have to rev match to double clutch. If you rev matched you wouldn't need to double clutch. Rev matching is where you match the revs on the engine with the revs of the gears in the tranny so you don't need to use the clutch. I'll agree that it's not nice on the tranny though, learning where the revs match is where you will cause all the damage. And of course when you screw it all up...

You don't have to double clutch to keep the tranny in good shape. To be honest double clutching is basically pointless on modern cars, that's what the synchros are for. If you look after a tranny properly, and don't *ever* grind it, it wil last well past 200k. If you abuse the crap out of it, it won't last. And, IMO, it's a bad idea to jam your tranny into first when doing anymore than a couple of kph(or mph). So you'll prob find those beat up gearboxes had owners who would jam it into a different gear when they weren't supposed to :p
 

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rev matching with normal clutching and shifting helps alot, especially on old beat transmissions. I've been driving old toys with crapped out 3rd to 2nd gear syncros for so long that I always rev match on downshifts now. It without a doubt helps get the tranny into gear sooner and smoother.

Double clutching is kind of pointless now but may still be easier on the tranny in the long run, but not really worth the bother. Lucky Bob Sully's new car is a 1 owner deal, and the PO was an older gentlemen and always double clutched since day one lol. The tranny is sure in nice shape though, feels like new still.
 

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ma61_turbo said:
And, IMO, it's a bad idea to jam your tranny into first when doing anymore than a couple of kph(or mph). So you'll prob find those beat up gearboxes had owners who would jam it into a different gear when they weren't supposed to :p

On tight autocrosses you have to. But put the clutch in, go neutral, clutch out rev match, clutch in, downshift to first -- and all is gravy
 

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Old thread, but a subject that came to mind when driving today - and based on these older replys and my driving habits here are my comments:

* double clutching is easier on your trans when downshifting
* originally used when a "gear" (like 1st) was not fully synchonized (67 Mustang 6 banger 3 speed - first car)
* "rev matching involved"
* I do it as a habit - to be gentle to the tranny internals
* basically you - clutch - rev the gas - clutch again - then down shift (the revving of the gas/engine "matches" the speed of the lower gear that you are shifting into so there's no grinding - and you have smooth downshift
* I'm pretty sure this saves the tranny and prevents "bad things" from happening

Does anybody else "double clutch"? (or is it just us old guys)
 

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My first car was a rusty Mustang that always wanted to stall so I got damn good at half-footing the gas while braking. Because of that I've learned to rev-match my downshifts, thought I rarely go into 1st when downshifting (I'm usually almost stopped by then).

I've run forklifts and yard buddies that had straight cut gears and I always had to double clutch those puppies but don't bother with any of my modern cars. On that note, my 1990 Toyota truck is the sweetest trans I've ever owned. It's syncros are beautiful... I can pop it into first easy as pie when downshifting.
 

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Not unless I have to. And if I have to I know it's time to rebuild my transmission! Seriously, there's no reason to be shifting your Supra like it's some giant 22-wheeler.
Well to be honest, with that 6 foot tall stock Supra shifter it almost feels like driving a big rig with a split gear trans :)
 

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I aways double clutch I have a pretty mint Supra and I plan on keeping it that way. I had to do it when I was driving an old van without syncromesh and some old Minis with dodgy gearboxes. I agree that it may not be necessary to do it on newer cars or even our old Supras. But it's definately easier on the synchromesh, after all synchromesh involves metal on metal friction to match the speeds so the less these contacting components have to interact the better. Also it's pretty satisfying when the car slides into gear with no resistance at all, particularly when you are coming hot into a corner while also heel and toeing. Personally I feel it's silly not to double clutch.
 

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i would double clutch in 1st to 2nd and 2nd to third once in a while, cuz my synchro's were iffy and the trans wouldnt go into gear smoothly. or, not as smooth as id like it, (i dont like to make my passengers bob their heads too much) but double clutching and rev matching? thats pointless...waste of time on a time'd course if u ask me.
 

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Yeah - it's a waste of time on a timed course, but for those of us concerned about preserving the MKII, it's a good thing!
 
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