The Art of Cog-Swapping: Double Declutching

Many, many years ago, when UMPH was but a boy, double de-clutching was considered de rigeur for drivers with sporting aspirations (or should that be pretensions?).  The fact that synchromesh had been well and truly invented decades earlier didn't diminish the allure of blipping the throttle on down-shifts, signalling to anyone within earshot that you really knew your stuff.  Or that's what UMPH thought, anyway. 

The fact is that double de-clutching isn't really all that necessary, so long as your car's manual transmission has working synchro.  However, that's not to say that there aren't benefits to the practice and, if you own an earlier classic vehicle, it remains a skill that's pretty much essential if you don't want the ignominy of grating your gears, which will inevitably occur just when your pride and joy's attracted some admirers and you're trying to look nonchalant as you're cruising by.

For the uninitiated, double de-clutching is where you disengage, re-engage, re-disengage and re-re-engage your clutch whilst changing from one gear to another.  Sounds complicated, eh?  

Adding to the complication is that you do not blip your throttle on up-changes.  Doing so would really mark you as the, umm ... , novice that you clearly would be.  The reason?  In simple terms, throttle-blipping serves to speed up engine revolutions so that they are better matched to the lower gear that you're about to select.  Therefore, doing so changing up (to a higher gear requiring fewer engine revolutions) would be counter productive.

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Starting Out ... 

So, how does it work in practice?  Here's the simple UMPH step-by-step guide:  

1. Grab your gear shift whilst simultaneously depressing the clutch, releasing the throttle and moving from the gear you're in towards the gear you require;
2. as the gear shift approaches the neutral position, release the clutch and, if you are down-shifting, also blip your throttle at this point (please see above comments);
3. depress the clutch again; and
4. when the gear shift enters the position for the required gear, release the clutch again whilst reapplying throttle.

What might seem here to be a potentially jerky, unnecessarily complicated process will, with practice, soon become as natural and fluid as any other physical skill (think serving a tennis ball or swimming free-style, not that UMPH is particularly adept at either!).  If you've done it properly, the change will be very smooth.  This is especially true of down-shifts, which can be achieved rapidly and without the need to slowly re-engage the clutch to avoid jerking or snatching as the engine tries to reach the higher revs required because of the lower gear.  

Down-shifting does require a bit of practice to prefect, though, particularly when trying to judge how big a throttle-blip is needed to match the engine's revs to the lower gear that's been selected.  For example, a down-shift at relatively low speed, and thus minimal revs, only requires a small blip; higher-speeds need bigger blips.  When shifting across the 'box - ie: from 4th straight back to 2nd, without going through 3rd -  an even bigger blip is necessary to compensate for the greater difference between the ratios.

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When You're Really Clever ... 

Apparently, some  newer cars - DSG equipped VWs and certain high-performance Nissans, in particular - have a built-in facility that automatically blips the throttle on down-changes.  This is really handy because it allows smooth down-shifts under brakes, without the need for the driver to actually touch the throttle.  

For those of you - UMPH included - that either can't afford a high-spec new VW or Nissan or, quite likely, prefer to do as much as the driving as possible without resort to electronic wizardry, it is possible to replicate the process using nothing more high-tech than your own foot and ankle - what's known as heel / toe double de-clutching.  It works like this:

1. Place the ball of your right foot on the right-hand half of the brake pedal, ensuring that you have good contact and can fully and safely operate the brakes; and
2. double de-clutch, as described earlier, but as the gear shift reaches the neutral position and you're re-engaging the clutch, pivot your foot to the right so that it comes into contact with the left side of the throttle pedal to give it a blip.

This technique is also really useful if your car's fitted with a lumpy race-style cam or is otherwise prone to stalling at idling speeds, because it allows you to manipulate the throttle without having to take your foot off the brake pedal.  Very handy indeed on those frosty mornings when you can't quite get the choke set properly!

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A Note Regarding Footwear ...

Really swanky types sometimes wear sexy little driving shoes, some resembling regular athletic runners (Puma make a range of Ferrari motif versions) or others taking the form of loafers (Salvatore Ferragamo or The Original Car Shoe).  There's no doubt that such footwear does offer benefits, such as increased 'feel,' allowing the driver to receive more feedback from the car's pedals; better grip, to ensure his or her feet stay on the pedal they're meant to be on; and greater flexibility, making heel / toe shifting easier.

However, UMPH has found that a pair of deck shoes offers all the above benefits, without costing an arm and the very limb at the end of which said footwear is worn.  For example, well-known brands like Sperry Top-Siders ($117 - $156), Sebagos ($150) and Rockports all compare very favourably to the Ferragamos at a rather silly $417 (and that's on sale!).

Recommended

Also recommended

Not really recommended

Not even slightly recommended!

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The heel / toe technique will allow you to maintain braking and make smooth down-shifts, with the added bonus that doing so will signal to anyone within earshot, and who can see your brake-lights, that you really know your stuff.  Or that's what UMPH thinks, anyway.

U M P H. 

(uppermiddlepetrolhead.blogspot.com.au).

PS: Thanks to the GMan for his video skills.  Much appreciated.