Rally Racing Tips From Pro Driver Andrew Comrie-Picard

Photograph Courtesy Rally America

[Editor's Note: This article originally ran in the October 2010 issue of Grassroots Motorsports]

Piloting a rally car quickly and competitively requires a broad range of pretty unusual skills. Not only do you have to race on tarmac, gravel, snow and ice—sometimes all on the same stage—but you must also use some very specific techniques for handling this loose terrain. 

Most enthusiasts probably know the basic orthodoxies for racing on tarmac: Stay within the tire’s friction circle, use smooth inputs, finish your braking before you start your turning, and roll into the throttle while unwinding the wheel.

Great. Forget all that. Now you’re trying to manage a constant, 200-mile-long slide through the woods. Welcome to performance rally. 

Here you must extensively use left-foot braking, trail braking and slide braking. You never, ever lift when on the edge of control, even in a front- or all-wheel-drive car. And surprisingly, front-wheel-drive cars are typically faster than their rear-drive counterparts.

Some of these things may sound and feel counterintuitive to an experienced track driver, and for good reason. The rules are different here.

Slip Slidin’ Away

As soon as you make a serious control input on gravel or snow, you’re almost always beyond the tire’s friction circle and into what I call dynamic or sliding friction. That’s the challenge of most rally courses: The static friction circle of the given surface is very small, almost useless. Add to that the effect of loose gravel and dirt on the surface of the road—essentially you’re always in the marbles—and you’ll see that you’re almost constantly operating in the vast no man’s land outside the orthodox friction circle. 

Think of it this way: Spinning the wheels can be good. For every action there is an equal and opposite reaction, so a lot of your forward movement is a result of the kinetic energy put into those rocks and clumps of dirt thrown behind you. 

Additionally, a rally stage is usually composed of loose gravel or dirt covering hard-pack earth or clay. By spinning the wheels under acceleration, you clean off the surface to an extent and dig down to a better friction surface, achieving more traction.

And once you’re sliding, control inputs don’t have nearly the same effects they had while you were sticking. What does have a big effect while you’re sliding? Weight transfer. 

Since you have so little traction available, you rely on the delicate balance between relative traction at all four corners of the car. That means the steering is much less significant than throttle and brake application. 

The throttle and brakes can be used to transfer weight from end to end in the car. The basic procedure for moving a rally car through a slippery gravel or snow corner is to get it sliding and then manage the angle of the slide by transferring weight back and forth.  You can use the throttle and brake pedals like a pilot would to steer the rudder of an airplane. 

Here’s a typical approach to completing a rally corner: Start with quite a lot of rear brake bias and stand on the brakes—hard—at corner entry. With the weight now on the nose, use trail braking to initiate the turn and let the car’s rear step out and start to slide. The rear brake bias will help you ensure oversteer as well. 

The sliding will help you in your braking, too. Most rally tires feature outside tread blocks with sharp edges that slow the car in two ways: They carve through the loose gravel and also dig down through soft dirt to the harder surface below. 

If you time this braking and sliding just right, you will arrive at your turn-in point with the car at an optimum angle to slide through the corner. What’s the optimum angle? This varies a little with driveline type, but basically the idea is to have the drive wheels clawing into the apex to pull you around. In other words, the steering wheel should generally be pointed at dead center, as you’re relying on the spinning wheels to claw around the corner. Now that you’re pointed in the right direction, get on the throttle, transfer weight to the rear, and dig around the corner. 

Here’s where you really start to play with the weight transfer. When you’re on a race track and sticking, weight transfer will increase the size of the static friction circle and thus increase your thresholds for braking, steering, cornering or accelerating. However, when you’re already beyond those thresholds and sliding, weight transfer will completely change the attitude and direction of the car. This is, essentially, how you steer. 

For example, if you’re mid-corner and you need to tighten the line, you might press the brakes without lifting the throttle. This slightly sheds some speed from all four wheels, slowing the car just a hair. It puts more weight on the front wheels so that, without you steering at all, the car yaws into the apex. 

When the time comes to blast down the next straight, just let off the brakes, stay on the throttle, and let the weight transfer to the rear. Possibly add a little counter-steering, open your line, and straighten out the car. If you’ve accomplished all of this correctly, you’ve probably only done a little steering with the wheel—some at initiation and maybe a little at the end of the corner. The rest of the turning was done with weight transfer.

The throttle can be used to control corner attitude quite effectively. Here are the basics: 1) Minimal steering input on approach begins to set the car in the proper attitude for the corner. 2) When the car slows under braking, weight transfers forward and increases the available grip of the front wheels. 3) The rear wheels now have reduced grip relative to the front wheels, allowing them to step out and point the car into the corner. Photography Credit: Ken Neher

Advanced Techniques

Of course, the corner just described is the ideal. Often you’ll have to work under less-than-rosy conditions. 

In very tight, slow-speed corners like hairpins and switchbacks, for example, you may find it difficult to get enough weight on the nose to initiate oversteer. Here you can use the hand brake to begin the rotation and hang out the back of the car.

However, get back on the throttle as early as possible to restart that forward momentum. Many people over-rotate these very tight turns and slide to a stop. 

Then there’s the famous pendulum turn, also known as the Scandinavian flick. This is when a driver turns away from the corner before turning into it. For me, this move works when I’m going slightly too slow to initiate trail-braking oversteer. It’s also useful for times when I’m carrying so much speed down a narrow road that sliding into the corner won’t give me enough braking before reaching the turn-in point. 

Here’s how it’s done: First, steer away from the corner to accomplish some braking. When it’s time to aim for the turn, get out of the brakes and blip the throttle, transferring weight to the rear and snapping the car into the corner. Then, get back on the throttle to transfer weight back to the rear; hold the line and pull the car around the turn. Modulate the throttle and brake as needed to adjust the line.

Different Surfaces, Similar Techniques

Racing on slippery surfaces is unlike track racing in many ways, but oddly, rally techniques rarely change. For example, a snow and ice rally effectively uses the same techniques found in a gravel rally—except that all of the control inputs have to be done way, way ahead of time, and corrections have much less effect on the more slippery surface.

Think of the differences this way: If racing a formula car is like piloting a jet plane and rallying on gravel is like driving a jet boat, then rallying on snow and ice is like piloting an ocean liner. A wet, muddy rally? Maybe that’s like racing a fast houseboat.

Tarmac rallying does require a shift in technique and, frankly, it’s a hybrid of the rally approach and orthodox track tactics. Sometimes the surface is good and you’re sticking, working the compound of the tire and following traditional track techniques. In reality, though, the surface is usually cold, broken, uneven or dirty. Traction barely exists, and you’re right back into the rally approach. Rally drivers must be versatile enough to handle all of these surfaces, which is why they’re so often respected by racers from different disciplines.

Left-Foot Braking

Most of us in rally use our left feet on the brakes, and there are several reasons for this. First, while delicately sliding through a corner, you want to be able to switch from throttle to brake faster than you can move your right foot back and forth between the pedals. 

Second, quite often you want to apply the brakes while staying on the throttle. This stabilizes the car while at speed and in a corner. It also maintains boost in a turbo car.

If you’re in a front-wheel-drive car, left-foot braking while staying on the throttle is the classic way to initiate the corner. By keeping the engine loaded while applying the brakes, you slow the front wheels a bit and get some weight transfer to the front. This braking also slows the rear wheels more than the fronts and initiates oversteer. 

Once you’re pointed in the right direction, get off the brakes and allow the front wheels to pull you into the apex. This is why front-drive rally cars are now typically faster than their rear-drive counterparts: Left-foot braking turns the classic front-drive understeer on its head.

Pilots of front-wheel-drive cars can take full advantage of left-foot braking techniques. Left-foot braking can create predictable oversteer on corner entry; just release the brakes when the front wheels are pointed toward the proper apex. As this photo shows, minimal steering input is needed when the technique is done properly. Photography Credit: Ken Neher

Practice Makes Perfect

Some great rally drivers, of course, aren’t thinking about sliding and static friction—or even weight transfer or cleaning the surface or any of the other things I’ve talked about. That doesn’t make them any slower, of course. In fact, a couple of the guys I race against in the Rally America Championship are naturals like that, and I wish they weren’t so damn fast. 

But whether you’re a natural already or a rally driver in waiting, awareness of these techniques will give you something to build on. Now go out to your nearest gravel pit and start practicing to someday beat me.

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Comments
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fidelity101 (Forum Supporter)
fidelity101 (Forum Supporter) UltraDork
10/9/20 2:32 p.m.

I wish BFG still made rally tires, they were the bomb! Actually for many years I ran a set of take offs from ACP sometime when he was running the scion, I only sold them last year for what I paid for them after using them for years on end. 

irish44j (Forum Supporter)
irish44j (Forum Supporter) MegaDork
10/9/20 7:53 p.m.

No surprise FWD cars are often faster than RWD in the same classes. Most of the RWD cars people rally are from the 80s (aside from the few people doing the BRZ thing or Hooper's Lexuses), so it's a bunch of 30-year-old stuff where the "powerful" ones are like 200hp. 

Meanwhile, you can get 200hp++ in any number of modern, smaller and lighter, FWD cars with way more parts availability, etc. (Fiesta STs, for instance). 

But, they're not having nearly as much fun :)

--

The other part not mentioned about rally at high speeds: Going 100mph 5 feet away from big trees and huge drops into a river valley below is way scarier than going 100mph with a tire wall 100 feet away. I've almost never scared myself on a road course (in a 6-cyl e30), but I probably scare myself 50 times in any given rally (in a 6-cyl e30 going much slower). 

Also not mentioned: In rally, half the time you can't actually SEE where you're going or look ahead to link turns (many are blind, or you're in someone's dust, or it's dark). On the track you know the whole course after a few laps and can also usually see what's coming up.

 

RallyJon
RallyJon None
10/10/20 12:18 a.m.

ACP's as good a writer as he is a driver.

JG Pasterjak
JG Pasterjak Production/Art Director
10/10/20 9:32 p.m.
RallyJon said:

ACP's as good a writer as he is a driver.

'09 GT-R · '14 Cayenne Turbo S · Past: '02 996 C4S · '95 993 C4 · '71 911 RS look · '04 STI · '01 S4 Avant · '00 Impreza RS Turbo · '88 Celica Alltrac Rally Car

I was just sort of randomly scrolling through my Facebook feed recently and he was doing a live video just hanging out in his garage rebuilding some old carbs... wearing a GRM work shirt. Pretty cool.

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