(Updated on September 23, 2022)
Double-clutching is a specific method of shifting the gears of the car. This type of shifting is used for vehicles with unsynchronized manual transmissions and it requires a certain technique.
In the past, this technique was used for old cars, mostly heavy-duty trucks or even some racing cars. Nowadays, double clutching is no longer required, as most vehicles have a synchronized manual transmission which makes this technique no longer useful.
However, there are still some situations in which it may be useful.
Why Double Clutch?
For example, if you are travelling with the transmission in neutral and you are going to soon stop your car at a red light, but suddenly it turns green and you want to get the car in the first gear, it won’t be a smooth process.
This happens because your speed is higher for the gear to accept it. In this case, by double clutching your car, you are able to get your car in the first gear in a much smoother way and without damaging the synchronizers in the transmission of your car.
The aim of the double-clutch technique is to assist in coordinating the revolving speed of the input shaft being driven by the engine to the revolving speed of the gear the driver wishes to proceed with.
On the other hand, the output shaft in the transmission is directly driven by the revolving wheels, and individually, the gear set is a different contrasting ratio. Therefore, in order to move down, the 4th gear needs to be static, leaving no gears connected to the input shaft.
Three main reasons why you would need to use the double clutch:
- You are driving a car with unsynchronized transmission
- You have an old car with worn synchronizers (in this case double clutching is only needed for downshifting)
- You are driving an old-school racing car
How to Double Clutch
Here’s how to complete a proper double-clutch shift in 7 easy steps:
- Push in the clutch pedal
- Place your shifter in N (neutral)
- Release the clutch pedal
- Tap the throttle
- Push in the clutch pedal one more time
- Place the shifter in the desired gear
- Release the clutch pedal
Basically, this technique requires pressing the clutch pedal once more between every shift. A good example of when to use this is:
If you are in 4th gear and you want to downshift into the 3rd gear, by following the steps mentioned above, you can make the shift smoother and at the same time prevent the synchronizers from being damaged. Even though it may seem difficult in the first place, it is actually something you can get used to very quickly.
- More efficient shifting
- Smoother shifting
- Extra step when shifting the gears
- No longer needed for synchronized manual transmissions
- Takes more effort, especially with a stiff clutch pedal
If you have a regular manual transmission, it most likely has synchronizers, so the process is much easier and it is no longer necessary to use double clutching. However, if the synchronizers of the transmission are worn, the option of double clutching may still be come in handy.