I have been reading up on this, I have heard of it but never seen any one do this.

Is this something that with some pratice any one could do?

And what is it exactly?

Any one know, I am looking for info as I type this.

Very interested to know.


Thanks.

 

Double clutching is how you shift a large truck (18-wheeler). You have to push the clutch in to take it out of gear, then again to put it into the next gear.

There is a way to shift without using the clutch at all, but I'd think you'd toast your trans practicing. You basically have to know what engine speed your vehicle will go in each gear, so that when you go to shift into the next gear, the transmission and the engine are already spinning at the proper rpm's to engage. I've done it on dirt bikes before, but I don't want to trash my car trying it out.

 

Double clutching is most useful in downshifting and especially when shifting into 1st if you're doing a rolling stop, not a complete stop, (and your first gear is not synchronized).

The fundamentals of double clutching: The clutch separates your engine from your transmission. Neutral separates the countershaft in the transmission from any of the drive gears. With your clutch pedal out, the transmission countershaft is connected to the engine. The idea of double clutching is to get the speed of your countershaft to match the speed of the drive gear that you are about to go into. Stay with me here.

If for instance you find there is some grinding when you're downshifting from 4th to 3rd for instance, even with the clutch all the way in, then double clutching will help you.

The way to do it (continuing with the 4th-to-3rd example, but works for any gear change): While in 4th and driving, put the clutch in, put the shifter into neutral, let the clutch out. Goose the throttle for a split second to race the engine, put the clutch back in, put it into 3rd, let the clutch out.

Since, at a given speed, the revs in 3rd gear will be higher than the revs in 4th gear, what you've accomplished by double clutching is matching the countershaft speed to the 3rd gear revs before you actually put it in 3rd gear, thus making the transition into 3rd smoother. It takes a little practice just to get used to it, but then it becomes second nature.

I collect old jeeps, where you must come to a complete stop to get it into 1st because 1st is not synchronized, so I became very adept at double clutching to allow me a rolling stop getting it into 1st. I now double clutch wehn downshifting any time, even in my '06 Mazda.

Double clutching when upshifting is less useful. You would do the same steps as above, but just don't goose the throttle. Since you want the 4th gear revs to be slower than 3rd when upshifting, you're intent is to slow the countershaft down closer to idle.

Long-winded response, but double clutching is fun, and it also lengthens the life of both clutch and transmission by making the transitions smoother.

Mark in MA

 

Cool thanks Mark