driving techniques, heel and toe -

Heel And Toe

***DISCLAIMER***

First a quick disclaimer. This technique is aimed at track driving ONLY and works best when heavily braking. We are not responsible if you try this on the road and put your pride and joy in a ditch or worse. Save these things for the track where it’s safe to try them out and learn, to start with at least.

Now the disclaimer is out of the way, this article aims to shed some light on the driving technique known as “heel and toe”. This technique is generally employed by racing drivers while driving on circuits and rally stages. I’ll discuss firstly what the technique actually involves and then more importantly why it’s actually a good idea to employ it on the racetrack.

So what exactly does “heel and toe” mean and why do we use it while driving on track? The technique itself is reasonably simple and is employed under heavy braking where downshifts are required. It allows the throttle to be “blipped” while changing down gears to match the engine speed to the road speed in the new gear. This allows a smooth downshift to take place without any jerky movements or excessive spiking of engine revs.

There are two main methods which people employ dependent on pedal position and foot size among other things. The first method that is used is a rotation of the ankle to the right to allow the driver to apply pressure on the throttle pedal with their heel to blip it, all while maintaining a braking force with the ball of the foot. This is the most conventional technique that most diagrams or videos will show. This technique is generally good for most pedal layouts as it allows for varied spacing between the throttle and brake. This is also the best technique to use when first starting out, if possible, as you maintain a good contact on the brake throughout with a low probability of your foot slipping off the pedal.

The second technique that can be used is a rolling motion of the foot to the right in order to blip the throttle. Here half the driver’s foot remains on the brake pedal to modulate pressure while the outer edge of the foot makes contact with the throttle itself.  This can be a risk, especially when first trying it, as if you try to blip too aggressively your foot can actually slip off the brake pedal altogether (not good!). This technique is more advantageous in cars with closely spaced pedals, or where there isn’t necessary room to rotate your knee (to cause rotation at your ankle) or foot due to the cabin layout of the car itself. A good example of this technique being employed is in the legendary video of Ayrton Senna in an NSX-R at Suzuka.

That’s all I’ll say on the technique itself as there are plenty of good tutorials and videos out there on the internet. What I will now discuss is why it’s a good idea to heel and toe on track.

The first and most obvious advantage you’ll see through heel and toeing is an increase in the clutch life of your race/track car. This is because you’re essentially doing part of the clutch’s job yourself with your inputs. The job of the clutch in a car is to ensure the engine speed (or speed of the crankshaft of the engine) matches the gearbox input shaft speed (the road speed of the car when a gear is engaged). It does this by connecting these two components with a degree of slip, allowing any differences between the two components speeds to be eliminated by wearing the frictional material during slip on the friction plate of the clutch. Put simply the greater the difference between the two shaft speeds the greater the wear on the clutch friction material will be, hence reducing the life of the clutch itself.

On the road this speed differential isn’t usually an issue as deceleration is relatively gentle and maintaining low revs (using a high gear) of the engine isn’t a problem while decelerating.  This means the speed difference between the shafts is low, and therefore clutch wear is minimal. However on track where fast deceleration is necessary while keeping the engine in the powerband, to be ready for acceleration out of a corner, the difference between road and engine speed is much larger, thus creating the need to heel and toe. By heel and toeing you are already largely matching the speeds of the two shafts yourself, therefore reducing the amount of “work” (slipping) the clutch has to do and greatly increasing its life.

Heel and toeing correctly, in addition to reducing clutch wear, removes the large jerking motions generally associated with downshifting quickly. The jerk produced when downshifting without heel and toe is caused by the inertia of the engine itself being accelerated up to the road speed. This acceleration is avoided by utilising heel and toe, reducing fatigue on engine components. This also has a large benefit on reducing the general stresses throughout the drivetrain. This is because it reduces spikes of torque created by the engine inertia, through both the gearbox and driveshafts. This again increases component life and reduces the probability of failures.

So other than the mechanical benefits what other reasons are there for heel and toeing?  The main benefit that is gained is control during the braking phase of a corner, especially in low grip conditions such as the wet. The reason for this is that you as the driver want to be solely in control as to what is happening at the wheels. Without heel and toeing the additional drag from the engine getting up to speed during a gearshift creates drag through the driveline and has an additional braking effect on the driven wheels. So what? You might ask, we’re braking anyway so why is this an issue? The problem that this causes is when you’re in a track environment you’re generally braking to the limit of grip on the pedal anyway. This means there is then no “extra” grip available when additional braking is introduced from this driveline drag. This can cause the driven wheels to lock from this drag, reducing the drivers control over the vehicle at best, and causing a spin or crash at worse.

Also tied into the aspect of the driver being in control; generally going into a corner the driver wants a consistent amount of weight (and therefore grip) at the front wheels to aid braking and turning in. When not heel and toeing, the torque transmitted through the driveline causes a front-rear jerking motion. This creates weight transfer within the car and upsets the balance on corner entry. This lack of consistency makes it difficult to maximize the performance available to the driver, as sudden under or oversteer can be induced due to the transfer. This reduces driver confidence as well as hindering lap on lap consistency.

So that’s a start on heel and toe technique and some reasons why it’s a good idea to use it. Check out some examples of both our drivers employing the technique here, along with some dramatic driving around Donington Park at a preseason test last year. A full lap of Donington with a camera on the driver’s feet is also available here.

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