Double Clutching: The Other Half of the Story

By Steve Tom

In his article, “Heel and Toe, and Double Clutch Techniques” (Moss Motoring Spring 1994), Chris Ball took the mystery out of this ancient British art. However, by describing only the technique for downshifting, he left out half the fun!

Double clutching (or double declutching, as the Brits call it) is a technique that can be used when either upshifting or downshifting. The purpose of double clutching is to match the speed of your gears to the speed of the car as you shift to the next higher or lower gear. In theory, this is done automatically by a device called a synchronizer.

Modern synchronizers work very well, but the classic British sports cars from the ’40s and ’50s came from the factory with synchronizers that could charitably be described as “anemic” at best, and only the top three gears were synchronized! Time has not improved their performance any, and the result is you have three choices when upshifting. You can grit your teeth and grind it into gear with a sickening “grunch,” you can shift v-e-r-y-s-1-o-w-l-y to give those tired old synchros time to do their thing or you can double clutch. (Very old sports cars, and cars with some racing gearboxes, have no synchronizers at all. Double clutching is essential for cars with these crashboxes.)

The key to understanding double clutching is to realize you are adjusting the speed of the input gears, which are connected to the engine through the clutch, with the speed of the output gears, which are connected to the rear axle. If you’re upshifting, say, from first to second, you need to use the engine to slow down the input gears. Push in the clutch, pull the gearshift into neutral and then let the clutch out again. Since you want to slow down the gears, take your foot off the gas and let the engine and the gears slow down. Now push in the clutch again (understand why they call it double clutching?), pull the gearshift into second and let out the clutch. If you’ve done it right, the gears and the engine will be spinning at the right speed for second gear and the shift will be smooth and noiseless.

Unfortunately, very few people get it tight the first time. Most likely, the car will lurch and grind much worse than if you had just yanked it from one gear to the next. Keep trying, and with a little practice you’ll be amazed at how much smoother, and faster, this is than trying to upshift without double clutching.

When downshifting the technique is almost the same, but the purpose is to speed up the gears. When shifting from third to second, for example, you push in the clutch, pull the gear lever into neutral, let up the clutch, blip the throttle (rev the engine briefly) to speed up the gears, then push in the clutch again, pull the gear lever into second and let out the clutch. Sound simple? Try it!

Ouch!! Like upshifting, it takes practice to get it right. Blipping the throttle just the right amount is part of the secret, as is doing the whole procedure quickly enough so the gears don’t slow down again before you shift. With a little practice, your shifts will be smooth, quiet and effortless. You can even downshift into first without coming to a complete stop!

Once you’ve mastered the art of double clutching, you’re ready to move on to the heel-and-toe downshift technique Chris described. This will definitely put you in a league with the pros, and you’ll have mastered an art that Datsun drivers don’t even dream of.

Of course, if you drive a modern car with good synchronizers, you really don’t need to double clutch, but then again, there’s no reason why you can’t do it anyway. I double clutch my MGTC out of necessity, and I double clutch my MGB for the pure fun of it. It makes a lovely sound as I head into a tight hairpin, and I just might be helping my under-worked synchronizers live to a ripe old age!