How to heel toe downshift

Source: T.M.O.F via Wikimedia Commons CC BY-SA 2.0

Hang around car enthusiasts and your ear is bound to catch fancy sounding motoring jargon that will make you just glaze your eyes. Today, I am going to throw another fancy motoring terms that will make anyone who lives and breathes cars weak in the knees - the heel toe downshift.

Is it some kind of dance move I hear you say? Well, pretty much, just not the heel toe flick you see in hip hop dance. Rather, it's a driving technique applicable on manual transmission cars that involve your right foot covering the brake pedal with the toe and your heel blipping (a quick and sharp jab) the throttle without releasing the brake as your left foot dip the clutch as usual during a braking and downshifting scenario. This is usually applied as you approach a corner.

Sounds like a lot is going on within a short time frame. It may sound intimidating, but with practice it should be natural enough that you can do it in your sleep. Before we get on with step-by-step tutorial, let's start with the why behind its application. 

Why Heel Toe Downshift? 

Heel toe downshift saw the light of day due to the working principle of a manual transmission. Observe the tachometer as you dip the clutch and you will notice the rpm drops to idling speed. Select a lower gear and let the clutch out, notice the rpm suddenly spikes up from idle to whatever rpm it should be for the lower gear. Due to the abrupt manner the engine picks up speed, the car will jolt and gives off a sensation like you just slam on the brake hard.

The resultant jerky motion is due to the mismatch between the engine speed and road speed relative to the selected gear. Let me give you a simple scenario.

Say you're cruising down a highway at 60 kph in 4th gear at 2000 rpm. Then, you dip the brake slowing the car down to 40 kph, downshift to 3rd gear (engine speed drops to idle at this point) and let the clutch out. The engine immediately jumps to roughly 3000 rpm as the clutch engages, followed by that all-familiar head bobbing.

This can be explained by the physics that take place inside the transmission when you execute the downshift, as succinctly explained by Jason Fenske of Engineering Explained below:

Basically, as long as you're off the clutch driving as normal, everything from the engine to the clutch plate to the input shaft and finally to the output shaft spins together.

The moment you depress the clutch, you separate the clutch plate from the flywheel (a spinning metal that spins with the engine), causing the latter to slow down. As 4th gear is still engaged, the clutch plate continues to spin at 4th gear speed. Shift the shifter into 3rd and everything in the transmission including the clutch plate speeds up. 

Going back to the scenario I had given above, the clutch plate will rotate at 3000 rpm while the engine, since it's no longer connected to the transmission, drops to idling speed (maybe around 1500 rpm). Mate the clutch plate that spins at 3000 rpm with the flywheel rotating at 1500 rpm, the fast spinning clutch will force the engine to speed up to match the clutch plate's rotational speed. As the transition is abrupt, a 'braking-like' thrust is felt, identifiable from the unpleasant jerky motion.

There's where heel toe comes in. Before you release the clutch pedal, give the throttle a blip while maintaining brake pressure to raise the rpm to match the speed of the clutch plate. If the speed match, you have a nice, smooth, jerk-free downshift.

Before I move on to the steps, a few tidbits is in the card. Heel toe is a misnomer in modern context. I've seen many different variations that don't coincide with the namesake due to varying pedal spacing and the size of individual foot. For instance, some people with big feet blip the throttle by rolling the 'half' side of their foot instead of their heel. My advice is do some experimentation until you find your most comfortable variation.

How to Heel Toe?

1) Apply the brake. In my case, I am using my toe.

2) Clutch in.

       + 

3) While maintaining brake pressure, pivot your right foot over the throttle pedal. Depending on individual and pedal layout, the throttle blip can be done either with the traditional heel on throttle, or the modern 'side of the foot' method. In my case here, I sort of use the latter method. Nonetheless, use whatever variation you're comfortable with, which comes with experimentation.

4) Engage new lower gear.

5) Let the clutch out and continue braking until safe speed has been established. How to know if you've matched the revs? Let the clutch out fast. Yep, don't release slowly as taught by your driving school as that will only mask the effect. You have to let the clutch out as rapid as you can. If there's little to no jerking, you've successfully match the revs. If the car jolts violently, your blip is off.

The good news is your blip doesn't have to be perfect. In fact, don't stress yourself out trying to hit the exact 'magic' number. It's okay if you're off by a small margin like being off by 200 or 300 rpm.

Also, if you're just starting to learn to heel toe, practice the coordination with the car stationary. Once you're comfortable, find a stretch of road sparse of traffic or even better an empty parking lot and put the foot coordination into practice. Throw downshifting into the equation so your body will acclimatise to the hand and foot coordination and to the sound of the engine. 

This will take practice so don't throw in the towel if you don't get it right from day one. With practice, the coordination will become second nature and your ear will just 'know' when the revs match. 

Benefits

1) The most oft-cited upside is arguably the reduction in wear and tear on the clutch as it will experience less slippage (hence less heat production) from the reduction in speed differential between the engine and transmission. However, I believe this depends on the driver skill as a poorly executed heel toe can potentially inflict more damage to the moving parts. 

2) A well-executed heel toe downshift makes for a smoother ride as you and your passenger will endure less head bobbing from a poor downshift.

3) It's damn fun when you get it right!

Should you learn to Heel Toe?

Some skills are nice to have but not essential. Heel toe falls in that category. It's not a requirement for a safe and efficient A to B drive, but there's no harm if you're interested in giving it a shot.

Once you do get it down, it can admittedly be addictive!