The Easy Way to Double Clutch
The Easy Way to Double Clutch
This is a easy approach to learning how to double clutch. The
double clutching technique allows downshifts from higher speeds
without any synchroniser wear. If you want to drive really
quickly and keep your transmission intact for extended periods
double clutching is very important!
Double clutching is the proper way to downshift at speed
without placing excessive wear on the transmission's
synchronizers. This allows you to select a much lower gear
without the tell-tale lurch you normally get when the clutch is
let out after downshifting.
When downshifting 4th gear to 2nd at 50 mph, you need to raise
the engine speed from 2200 rpm to 5000. To prevent excessive
synchroniser wear, the clutch is depressed and the shifter is
moved to neutral. The clutch is then released, and the gas is
depressed to bring the engine speed up to where it needs to be
for the lower gear. The clutch is then depressed again and the
shift lever moved into the lower gear. When the clutch is
released the second time, the engine is already turning the
proper speed . While this sounds complicated, it's easier done
than said, and only takes about a second to double clutch.
To better understand how the double clutch process works, a
little background on transmission fundamentals will help.
A typical transmisson has two shafts, one connected to the
engine through the clutch, and one connected to the rear wheels.
There are usually four to six sets of gears on these shafts and
they are selected with the gearshift lever inside the car. When
changing gears, the clutch is depressed to disconnect the engine
from the transmission so there isn't any stress on the moving
parts. Since the output shaft is permanently connected to the
rear wheels, the only way to match the speed of the two shafts
is to use the throttle to adjust engine speed.
Once the engine is turning the right rpm, both shafts will be
turning the same speed, and the gear lever will fall into gear
WITHOUT using the clutch! (Although most of the time you are
shifting too fast to be that accurate)
EXCERCISES
1) With the car idling in neutral, slowly step on the gas until
the engine is turning 3500 rpm. Do it again bringing the rpm's
up more and more quickly until you can give the pedal a quick
stab and have the revs stop where you want . As you shorten the
time allowed to match revs, you will notice it takes more
throttle. In fast driving, you will be shifting so fast 4 will
take full thottle! Now try matching revs at 4000 rpm.
2) Find a deserted road, and maintain 40 mph in 4th gear. Now
shift into 3rd, and see how many rpm's the engine speed
increased. At this speed, the difference won't be very much -
maybe only a few hundred rpm. Go back into 4th gear. This time
put the clutch in, push the lever to neutral and let the clutch
back out. You are now coasting with the clutch out. Raise the
engine speed to where it will be in third gear. Quickly push the
clutch in, select 3rd gear, and let the clutch out. There should
be no perceptible lurch if you accurately matched revs. Try the
same thing at higher and higher speeds. As the road speed goes
up, the speed difference between gears will go up as well. When
going from 5th to 3rd a highway speeds, you may end up within
1000 rpm of redline. The easiest way of determining your maximum
downshift speed is to watch the tach and speedo as you are
shifting up at redline. If you shift at redline from 2nd to 3rd
at 60 mph, subtract 10 mph, and that becomes your effective
maximum downshift point for 2nd gear. If are within 10 mph, you
are better off staying in the higher gear.
HEEL AND TOE DOWNSHIFTS
This combines double-clutching and braking into one event.
Place your foot on the brake as far to the right as you
comfortably can. While braking, roll your ankle so you can catch
the left edge of the gas pedal with the right edge of your foot.
If the pedals are too wide, try placing the ball of your foot on
the brake, and the heel on the gas (This is where the term
heel-and-toe originally came from). Now try gently slowing down
and downshifting. With practice, you can brake hard and
downshift in one smooth motion. This will prevent the wheels
from locking when the clutch is let out in the lower gear, and
you will be ready for a burst of acceleration coming out of your
favorite corner!