Double-clutching may be a nearly obsolete term today, as it is a method of shifting gears that largely applies to vehicles with an unsynchronized manual transmission, and is not necessary for vehicles with synchronized manual or automatic transmissions. However, it can be a useful technique to learn in certain situations.

The technique has become popular among truckers, as it can be difficult to shift gears in trucks. It can help prevent wear and tear on certain parts of the transmission and give drivers a boost of power. On top of that, double-clutching is beneficial as a backup plan when clutch linkage fails. Overall, double-clutching is about smoothly downshifting in order to accelerate.

Read on to find out more about how double-clutching works and in which scenarios double-clutching proves the most useful.

What Is Double-Clutching?

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While regular shifting describes the process of methodically sequencing up or down through the gears, other techniques exist for changing gears in certain situations, which can speed up or otherwise improve changing gears for more speed.

One of these techniques is double-clutching, which engages the clutch twice in a row while changing gears. It isn't used to shift up because the process involves matching the engine speed with the desired gear as a goal. However, the engine's speed can only be directly affected when it isn’t in gear by increasing it using the accelerator.

For upshifts, the process of pressing the clutch and lifting off the accelerator drops the engine's speed sufficiently, followed by continued acceleration with a nearly unchanged transmission speed. While the wheels are still traveling nearly as fast as before, the reduction of engine speed matches the wheels to the gear desired to engage.

For downshifts, the speed of your engine needs to be higher than that of the wheels and transmission. This is when double-clutching proves ideal, instead of immediately shifting into the next gear, drivers would put it in neutral and release the clutch. Then tap the accelerator to increase both the engine and clutch speed, followed by the usual clutch press and gear selection. When practiced properly, the whole technique only takes about half a second.

Related: All 2021 Porsche 718 Models Available With PDK Dual Clutch Transmission

Avoiding Overheating

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In most cars, the actual gears are in constant mesh and the vehicle's synchronizers decide which pair of gears to connect to their shaft.

However, most trucks and some racing cars showcase a non-synchromesh gearbox. Trucks tend to do this because they have so many gears and efficiency is actually increased by not having all of the gears in mesh continuously. By 2019, many models of cars no longer featured a manual transmission, making the point moot in most new vehicles. Trucks, on the other hand, retain their manual gearbox even as other cars are ditching theirs. Therefore, truck drivers still have to pay attention to the gears being balanced.

As a result, double-clutching is mandatory for shifting to occur in both trucks and racing cars. Speeds must be synchronized for the vehicle properly arrive in gear, and by doing so, not only is it more efficient, but overheating will be less likely, as the process will run much more smoothly and use less energy and heat.

Related: Ford's PowerShift Dual-Clutch Transmission Lawsuit: Full Story

It's A Solid Backup Plan

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Double-clutching is known to be a reliable backup plan for drivers to arrive home safely, as it can be effective when other methods fail.

For example, should the clutch linkage ever fail, drivers can still shift and get home by double-clutching, getting the engine and gears' speeds synchronized, and then easing the shifter into the right gear.

Clutches can malfunction approximately three times for every 1,050,000 miles driven, so depending on how long a driver owns a vehicle, they run the risk of this situation occurring. Electrical systems on a car can also malfunction and double-clutching can prove useful in that scenario as long as the electrical system hasn't completely shorted out.

Powering Into A Corner

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via MAT Foundry Group

Nowadays, double-clutching is considered to be largely redundant with transmissions advanced enough to incorporate the process into their mechanics through the use of synchronizers. These sit between the gears and the clutch to help match their speeds without the need for advanced shifting techniques. Double-clutching can be used for unusual circumstances such as powering into a corner or when overtaking a vehicle, both requiring the need to downshift quickly to accelerate. 

Coming up to a red light in neutral with the light turning green before stopping is one case where it's difficult to get the car into first gear. Double-clutching puts the transmission in first gear when the car is already moving, and it also may extend the life of the car's synchronizers.

Sources: electronicdesign.com, standardshift.com, matfoundrygroup.com, roadandtrack.com,

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