what id "double clutching"? how and why does this increase your performance?

Answer 1

Double clutching

When you are ready to either upshift or downshift:

1) push in the clutch
2) shift to neutral
3) let out the clutch (you are now coasting)
4) a) (applies to downshifting) rev up the engine to match drive shaft rpm
4) b) (applies to upshifting) let the engine rpm slow down to match drive shaft rpm
5) push in the clutch
6) shift into your intended next gear

You do this all real fast without thinking, like a reflex. It takes practice.


For the performance benefit:

As all racers know, you want to run at high rpms because you get more manuverability and control. If you are bogging down, you downshift to get your engine rpms up. So, double clutching increases your performance if you are downshifting because you can get back in gear quicker (you get back in the race quicker, so to speak)

For truckers, the performance benefit is critical. If you are going up a steep incline very slowly with a heavy load and have to downshift, you double clutch and get in the next lower gear before you loose you brief upward momentum thereby keeping torque and power to the rear wheels without rolling back downhill or getting stuck. Again, like in racing, you double clutch because you can get back into gear quicker and maintain control of your truck. I used to do this alot with 1937 and 1946 Chevrolet 2-ton dump trucks because these old trucks had 216 cu.in. six cylinder engines and they were not powerful enough to cross-country with a load if you could not double clutch and keep the rpms up.

There's no performance benefit to double clutching when you upshift.

But if you have no syncromesh when you are either upshifting or downshifting, you have to double clutch to avoid grinding gears.

Answer 2

It really doesn't increase performance. Double clutching is used on heavy (trucks, dump trucks, etc) vehicles that have a manual transmission. When the driver wants to shift from one gear to the next, he depresses the clutch and as he moves the shifter through the neutral position he releases the clutch and again depresses the clutch and shifts into the next gear. This helps spin up the gears in the transmission so that there is less gear clash when he moves the shifter to the next gear.

Answer 3

Double clutching is when you increase your engine speed to match the transmission speed when you are downshifting. For instance, if you're doing 60 MPH in 5th gear, and you want to go to 4th gear, you first push the clutch in and add a little gas to bring the RPMs up to about where the engine would be for 4th gear at that speed. Shift to 4th gear, then release the clutch.

I don't know if this increases performance as much as it saves your transmission. You have synchronizers on your gears that allow you to downshift easily without having to double clutch. If you abuse the synchronizers by downshifting too fast or too often, you wear them out quicker. Some transmissions, like heavy duty trucks and older cars have some gears that are not synchronized. When this happens, you must double clutch to downshift or else you will grind your gears in the transmission.

Answer 4

Double clutching doesn't help performance at all. When you shift from one gear to another, you momentarily let the clutch pedal out while you are in the neutral pos. This makes the trans. gears spin closer to the speed of the eng, so the gear change will be smother and not cause grinding of the gears.

With modern syncro transmissions, (in cars and small trucks) double clutching is not necessary at all. Truckers do it all the time.

Answer 5

First two answers are good.

karrivasara described rev matching, not double clutching.

Double clutching = hitting the clutch once as the shifter is removed from a gear, letting it out, and hitting it again as you enter the next gear.

Rev matching = using the gas pedal during a down shift in order to match the engine speed to the faster gear speed of the lower gear.