The Art of Heel-Toe Downshifting
Why heel-toe downshift? When you are racing a car - or driving it within the higher RPM range during spirited jaunts - downshifting to a lower gear causes a mismatch between engine speed and wheel speed. The engine is spinning at X RPM's, and the driven wheels are spinning at Y RPM's. That X/Y difference in RPM's causes two things:
- The engine to speed up to the RPM's of the wheels if there is more traction than engine resistance, which there usually is. This will be the spike in engine RPM's you'll see and hear from your car (that "vrooooom" sound from the engine). Essentially, this would be like traveling in 6th gear at 70mph on the highway (let's say at 3000RPM) then shifting into 3rd gear and dropping the clutch while maintaining the 70mph. The engine speed will spike (let's say to 6000RPM) and the car will violently slow down and lurch forward. Not a pleasant feeling!
- The wheels to speed up to the engine RPM's if there is less traction than engine resistance. When this happens, the tires will chirp - or worse-off, lockup - when you release the clutch pedal and enter the lower gear. Think of how an airplane comes in for a landing, the wheels on the landing gear are stopped, because they have no momentum. When the tires hit the runway, they immediately are forced to equal the speed of the airplane - which is physically impossible unless the wheels are already spinning - so you always hear a "chirp" and see a puff of smoke as the tires slide for the brief moment between hitting the runway and equaling the speed of the airplane.
This scenario is not a big deal on a heavy aircraft carrying so much momentum that will not even flinch from the brief moment of traction loss. On a lightweight automobile however, the loss of traction in the driven wheels (specifically rear wheels) can cause the car to become unsettled, especially if traveling into a corner with a great deal of momentum and side-load (cornering load), on the brakes heavy, and presumably with no more available traction to spare (Remember the "traction circle"? This is another post's subject matter if you are not familiar!). Barring a lesson in physics, you can probably assume how weight transfer works in terms of automobiles:
- A car under heavy braking will have almost all of its weight on the front tires/wheels, like a 300lb person on one side of a see-saw and a 50lb person on the other end. The heavier person's side will be on the ground, and the lighter person's will be in the air. There is still a little bit of weight resisting the balance change, but not much. This is how an automobile works under maximum braking conditions, so you can imagine how little traction the rear tires will have from the braking imbalance, which translates into how easily they can lose traction if the driver inputs are not smooth and controlled.
It's probably obvious now to you why matching engine RPM's with wheel speed (aka: heel-toe downshifting) is so important when racing, and why our Accel Grip pedal can be so beneficial to those who desire to practice this art. I call it an "art" because it's not something that comes naturally when driving, and most certainly is not something you would ever need to practice in your everyday driving routine, so just like any "secondary" technique that is not subconscious in nature (i.e.: bouncing a ball while walking), it must be practiced until it is subconscious, which means that you "don't have to think about performing the action, you just do it automatically". And as with any "art", the more one practices, the better they get at it. In essence, Heel-Toe Downshifting is the art of "hitting the ground with your feet running" as to provide a smooth transition between the gear you were in, and the gear you need to be in, coming through - and out of - the corner.
So now that you know why you should heel-toe downshift, how does one do it? Here are my recommended steps in practicing heel-toe downshifting:
- Clearly, you need a car with a manual transmission! Automatic transmissions will automatically rev-match when downshifting (Ever notice the smoothness between switching gears as you're slowing in an automatic transmission? This is what you want to achieve with your heel-toe technique!)
- Make it easy on yourself, which includes modifying your accelerator (gas) pedal to extend it closer to the brake pedal. The closer it is to your foot while it is pressing down on the brake pedal, the easier it will be to "blip" the accelerator during a downshift. The easiest way to do this is to add a pedal cover that is designed for heel-toe downshifting, such as our <a href="https://5xracing.com/i-23993215-5x-racing-accel-grip-pedal.html" target="_blank">Accel Grip Pedal</a>
- Find a technique that works for you. The concept is simple: figure out a way to tap the accelerator with a part of your foot at the same time is it holding down the brake pedal. Although this seems a simple task, there are several ways to perform the task, and no method/technique is wrong, as the only thing that matters is you are tapping the throttle to spike the RPM's to match the wheel speed when the clutch is released. How you get there is not important!
- The most widely taught technique is to actually use your heel to tap the accelerator pedal while the ball of your foot presses down on the brake pedal. I personally find this method difficult, as it goes against your knee and ankles natural range of movement. I also do not like this method as it causes you to lift your heel off of the floor, which causes the now floating ball of your foot to have less control and quicker - less smooth - movements, as it's lost its pivot point (your heel). This translates into jerky and quick movements on the brake pedal as the foot has lost its support pivot, which then translates into the car being "jerky" while braking. It also will cause you to over slow the car into a corner when racing, which is time lost. In a worse case, it is also dangerous because the driver of the car following you into the corner will not expect the car ahead of it to stop as suddenly (or jerky), and this "brake check" can cause the car behind you to bump you, especially in classes where the racing is super close (like Spec Miata) and bump-drafting down the straightaway is a very common practice.
- To try this method: Simply sit in a chair, extend your legs, and try to point your right toes towards your left foot. Do you find it easy, or can you feel the muscles in your right leg tensing up as you struggle to move your right toes past the 11 o'clock area? Better yet, sit in your car and try it to see how it feels.
- The method I find works best for me is what I call the "tilt" method. The "tilt method" is a method that I started using naturally before I learned the commonly taught heel-toe technique (as stated above). This method involves keeping your heel planted on the floorboard and simply "tilting" the edge of your shoe (right side of course) down and over to tap the accelerator pedal while braking. To use this method, you'll of course need an extended accelerator pedal to help bring it closer to the brake pedal, as the two pedals are too far apart in stock form to perform this technique, but that's what products like our <a href="https://5xracing.com/i-23993215-5x-racing-accel-grip-pedal.html" target="_blank">Accel Grip Pedal</a> are for! I like this technique because I find it much smoother and controlled than the original technique, as your heel is always planted on the floor and not floating.
- To try this method and to test my theory on smoothness: standing (to simulate the pressure you need to depress a brake pedal under full braking), with your feet flat on the ground, see how fast you can tilt the right side of your right foot towards the floor and back again, or how fast you can lift the left side of your foot and back down again.
- Now to compare it with the original method: remain standing and while keeping the ball of your foot on the floor, try to accurately lift your heel and tap the ground 3" to the right of it, then back to the starting point again.
- Now to compare the two techniques and ask yourself these questions:
- How fast can you do this in a controlled manner?
- Do you hear your heel banging on the floor?
- Did you hear your foot at all with the tilt method?
- Which method starts burning your muscles first when done multiple times in a row?
It should be clear to you that the tilt method is way more controlled and precise than the original method. If it's not and the original method is more natural and comfortable, by all means go with it! As I said above, there is no "right way" to perform heel-toe downshifts; the only thing that matters is that you find a comfortable - and consistent - method of doing it. You'll find that the more you practice, the more subconscious the action will be, leading up to it becoming a natural reflex and not something you need to think about. After a few weeks of daily driving and practicing heel-toe on EVERY downshift I made, it was something (and still is something) I automatically do every time I downshift a manual transmission car. My brain is programmed to do it, which is what you should be trying to achieve as a race driver, or simply as an educated "extracurricular" driver that enjoys advanced driving techniques and that spirited jaunt through the interstate cloverleaf or mountain back road. If you find yourself on the racetrack one day, it is one less technique among many needed to wheel a car consistently around a racetrack lap after lap. And with consistency comes speed as they say!
Here are some examples of heel-toe downshifting. These are great examples to visualize my explanations, and they prove that no technique is "wrong", and what matters most is you find the method that works for you and is smooth. See if you can spot the differences between the techniques and which looks easiest/difficult:
Some of my favorite "pedal cams" come from the Australian V8 Supercars of Australia:
Here's a good look at the amount of heel swing with the original technique in a British Touring Car:
Not all Aussie V8 guys use the original technique! Here's a fantastic example of my "tilt" method used in an Australian V8 Supercar:
And who better to provide an example of my "tilt" technique than the legend himself Ayrton Senna? Expensive Italian loafers and all!
As a bonus, here's an interesting look at a super advanced technique: left foot braking (it's a sequential shift transmission with no clutch required):
Once I can get some video, I'll post my heel-toe technique using our Accel Grip Pedal in our Miata.