Have you ever done double-clutching on your car? Double clutching had been used for old cars and some race cars a long time ago. But this technique is still widely used today for manual vehicles. Do you ever wonder why?
Continue reading and we will tell you later.
If you still don’t know how to double-clutch, then this article is for you. You should know by now that fast driving is all about the stability of a vehicle when turning, skidding, or braking.
Using the double-clutching technique to change to a lower gear, the driver will have firm control of the car even at higher speeds. Sounds better.
A double-clutching, also known as ‘double de-clutching’ in countries outside of the US (such as the UK and other European countries) and ‘double shuffle in’ Australia, is a driving technique used in manual transmission vehicles. Interestingly, before the advent of automatic transmission systems, double-clutching on manual transmission vehicles was a normal thing.
Furthermore, before car engines could precisely match the speed of the gear with that of the shaft, doing a double-clutch was widespread. When doing double-clutching, your feet will be utilized simultaneously in such precision that you shift gears while accelerating.
To put it simply, double-clutching is a driving skill of shifting gears from high to low (and vice-versa) gears that enable a smooth and prolonged transition. This is the reason why double-clutching is so popular in car racing where overtaking at high speed is common.
This question always pops up whenever double-clutching is talked about. A clutch is designed to act as a cushion between the engine and the transmission. When speeds are mismatched, the clutch merely synchronizes the two systems.
While the rotating speed of the transmission shaft is entirely dependent on what gear the transmission is, when you use the lower gear, the gear rotates faster than the transmission output. However, in high gears, the transmission output shaft will rotate almost the same as the engine’s speed.
The relationships between the gears and the engine speeds correlate with each other, so you have the following reasons on why the need for double-clutching:
Doing a double-clutching assures that when you do a downshifting, the driving speed remains constant. This will coincide with the gearbox and the vehicle’s acceleration.
Double-clutching is the best way to do when you want to shift from one gear to the next by by-passing gear or gears in-between them. This is especially if you want to shift to a lower gear (from a higher gear) to slow down without banging on the brakes.
In ordinary conditions, if you try to shift a gear when downshifting, it may result in a jolting movement that could slow you down or even stop your car.
The prolonged transmission is ideal for race cars. This is because, in normal circumstances (no double-clutching), shifting gear to the next takes some time for the system to be synchronized.
On car racing, this waiting time may cause you to lose the competition. Utilizing double-clutching eliminates this waiting time so you have a smooth and quick transmission while you avoid using the brakes.
You might wonder what happens to the system when you double-clutch. The series of events corresponding to double-clutching is not really rocket science.
When shifting your manual transmission into gear, a collar that has a ‘dog teeth’ engages with the gear. The engine shaft then turns the layshaft rotating the engaged gear.
The gear then transmits its power through the collar into the driveshaft. The remaining gears drift until each is engaged.
As double-clutching was a norm years ago, some race cars still used this technique until this day. To double-clutch shift, the clutch pedal is pressed to free the engine from the transmission.
At this time, pressing the clutch pedal allows the collar to move into neutral even without engaging the ‘dog teeth’ in the side of the gear. When the pedal is released and the gas is hit to get the engine into the appropriate speed (RPM), the system is ready for the next gear. At this instance, the collar and the next gear are rotating a the same speed enabling the dog teeth to engage the gear.
When the engine hits the right RPM, this is the right timing to depress the clutch pedal for the second time. What happens here is that the collar is locked into place for the next gear. But you must remember that double-clutching should not be the reason behind a whining noise or other unusual sounds in your car when accelerating.
More car enthusiasts are claiming that double-clutching is not necessary for a vehicle with a synchronized transmission. But they also believed that the technique can be advantageous for smooth downshifting. Doing this technique to accelerate and done without a hitch, it avoids tear and wear on the synchronizers.
To prove our point, these are just some of the advantages of doing double-clutching, whether you have a synchronizer or not.
Starting normally with your current gear, if you want to shift from one gear to the next, you must first engage the clutch. Before moving to the next gear, let the gear stays at the neutral position and then move to the next gear in a smooth operation.
If you are doing the double-clutch for the first time, you should practice in a safe place, like an empty parking lot. It’s best to train in a place not frequented by people to avoid any untoward incident.
While doing double-clutching is not a difficult task, you might want to minimize the chances of something going wrong while you practice. Here’s how to do a double-clutch:
Continue driving then accelerate up to the third gear, as an example, and press the clutch in preparation of a normal gear shift. At this point, you are not yet accomplishing anything.
As the clutch is depressed at this time, move the gear into neutral then release the clutch. At this moment, you might be traveling at 25mph (about 40kph) while the transmission is in neutral.
While the car is still in a neutral position, you can press the gas pedal (accelerator) to increase the speed (RPM) of the engine. Hitting the gas briefly at this time will accelerate the RPM a little bit higher than the speed when you will be in the lower gear. In this condition, there will be a balance between the transmission and the engine speeds.
Without doubling-clutching, you could imagine what will happen when you just drag the transmission from the third to the second gear. The RPM will eventually shoot up faster than the speed of the gear which will have tremendous pressure and stress in the transmission. The aim here is to set the RPMs as close as possible to what they would be in downshifting before it happens.
At this point, your foot should be off the gas pedal. Then, press the clutch the second time (hence the name “double-clutch’).
Once you press the clutch again, shift the gear from neutral to the next gear (usually a lower gear).
Once you shifted to the lower gear, let your foot off from the clutch pedal after you have chosen the next gear. Releasing the clutch should be done in a quick succession unlike what would you normally do.
There you have it! Double-clutching is not really as hard as you think. However, it takes a lot of practice to master this technique which could bring more benefits to your car than harm. Double-clutching may also save you precious money as parts (such as brake pads, synchronizers, and clutch) will last longer than usual.
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Currently, almost all modern manual transmission cars are fitted with synchronizers which makes double-clutching sounds unnecessary. But as we go through history, large freight truck transmissions don’t have synchronizers.
What do synchronizers got to do with modern manual transmission cars? You see, synchronizers match the speed of the gear you are selecting to shift to the speed of the transmission output shaft.
The modern synchronizers eliminate the need to double-clutch which is primarily pressing the clutch pedal twice and rather than shifting the transmission to neutral, you can go straight to the next gear of your choice. However, there are certain conditions that a driver needs to double-clutch.
One specific condition is during a stop on a red light with the transmission in neutral. When the light turns green, you might find it hard to bring the vehicle into the first gear.
The reason for this is that the transmission output speed is not in sync with the engine and clutch speeds. Using the double-clutch technique at this instance, you will find it easier to maneuver your car.
Watch this video for a more visual explanation on how to double-clutch:
We firmly believed that this write-up will make your day right. So, you now know how to double-clutch, but are you doing it right? As we have said above, practice will make it perfect. Moreover, even if you have a brand new car, doing doubling-clutching earlier, the better for your gearbox.
However, double-clutching is more useful in a racing environment than doing it on regular cars. But it seems that double-clutching is also recommended for certain conditions to also prolong the life of your synchronizers (if your car has them), brake pads, and have a smooth ride and transmission without slamming your brakes.
Moreover, you have to understand and know the limits of your engine before you try doing a double-clutching. Also, remember that some cars tend to have a lower RPM range than other modern cars.
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