A skill which makes car driving smoother is the double clutching technique. The execution of this technique is far from simple, but it can be mastered with practice and time. It's a technique which can be used in cars with manual transmission. It's a trick which cannot be pulled off, if you have automatic transmission gear. Reason? Duh, because its automatic of course! One of the benefits of manual transmission is, that you can play a more active part in driving the car.
The double clutching technique is actually a maneuver used by race car drivers, that is not that popular among us lesser mortals or 'civilian' drivers. However, it's a useful technique to be mastered, as it can save your motor and clutch from wear and tear, which it would otherwise go through. This technique will make your driving smoother, especially on highways, where you can race at high speeds. To pull it off, it's vital that you have thorough knowledge of your car's power band and a feel for its RPM response.
Shifting Gears With the Double Clutching
If you have been observant, while driving your car with a manual transmission gear box, you may have noticed how the car lurches forward, when you downshift gears and the tachometer dances. This is in no way good for your clutch disk, motor or pressure plate. What can you do to prevent this? You shift to double clutch shifting!
When you make a gear downshift directly, the car gets a bump, which is a bit rough on your clutch. Repeated direct downshifting like this, will wear out the clutch very fast. Now, we don't want that, do we? Don't worry, all it takes to prevent this, is a paradigm shift in your gear changing philosophy. There is nothing very exotic about it. All it needs is some quick hands and a series of deft maneuvers, as we shall see. This technique can save some bucks, which you would normally have to spend in car repair, once the clutch succumbs to its wear and tear.
So, without further delay, let me give you the low down on this double clutching transmission technique. You can call the double clutching gear change philosophy a 'neutral' philosophy. That's because, it involves shifting to neutral gear, in between making a transition between two gears. What does this achieve? If you shift to neutral, between making the gear transition, it allows you to do some 'rev-matching', that is, it allows you to adjust the speed of motor between two gears. This lining up of motor speed makes the double clutch downshifting very smooth. It saves the clutch from the mauling it gets from direct gear downshifting.
Examples of Double Clutching Technique Usage
Let's revise with a live example. I have broken down the double clutching downshifting technique into steps for you.
Step # 1: Shift into Neutral and Disengage
Consider the gear downshifting from fourth gear to third gear. Try this on a trial basis first. Say, you are driving the car in fourth gear at about 35 miles per hour (i.e about 56 km/hr). Begin the double clutching downshifting maneuver, by pushing the clutch and shifting the car into neutral gear. Then slowly let up the pressure on the clutch pedal, until it finally disengages. Don't worry about the speed, for a moment.
Step # 2: Blip the Throttle
Once the clutch is disengaged, then RPM (revolutions per minute) begins to drop. Next, while your car is still in neutral gear, step hard and 'blip' the car's throttle by pressing down on the accelerator pedal very quickly. With that done, the once dipping RPM, will rise to a higher value. This happens because, the car is in neutral gear and there is no connection with the drive train, which would otherwise eat up the generated power of your car.
Step # 3: Change in to Lower Gear
Keep a check on the RPM dial and once it crosses or is around 4000 RPM, rapidly engage the clutch back again and change the gear to third. Then release the clutch. There you are, safely into third gear, without the normally nasty bump from direct gear change and without mauling your clutch disk by holding it down for long! That is one car problem less for you.
Okay, I know that must have been quite a lot to take in, in one go. Read it back again and write it down if you want. Try it out on your own and practice, until you can do it with consummate ease. Once you have practiced it long enough, you will get used to it and perform it on an instinctive level while driving.