One of the most common things I hear from my students is, “It is so backwards from everything I have done in asphalt racing!”.
Regardless of how successful a student might be in their asphalt experience, almost every one has their world flipped upside down when they first attempt to race on gravel (not literally of course, that would be a bad day). The principles of racing on gravel versus on asphalt are like parallel universes. Some things feel familiar and other things feel different enough to make you question reality.
There are a myriad of nuances we could cover on this topic, but let’s focus on three main differences.
The first is the inherent lack of grip. When racing on asphalt, there is an intrinsic level of grip between the tires and the asphalt. Barring any extreme circumstances, the driver can trust that the car will simply do what it’s told because of this higher threshold of grip, e.g., you turn the steering wheel, the car turns.
In gravel, there is no such guarantee. The threshold of grip on gravel is vastly lower. It can feel like driving on a bed of marbles. It is extremely easy for the tires of break free and loose grip. If you have ever driven in snowy conditions, it can feel a bit like that.
Because of this, we rely heavily on the concept of weight transfer to create more traction by pushing the tires harder into the surface. The characteristics of gravel force us to simplify what we are asking the car to do in any given moment. This consequentially ends up changing the way we approach our lines through a corner, bringing us on to our second difference.
Most drivers are familiar with the concept of the track racing line: “Outside, Inside, Outside.” This line allows track drivers to straighten out the corner and maximize forward acceleration while still in the turn. The traction from the asphalt makes it possible to simultaneously turn and accelerate through the corner.
However, in gravel it is all too easy to overwhelm the tires. They only have so much to give. So instead of blending their available traction for cornering and accelerating, we separate their tasks between straight line acceleration/braking and cornering. This leads to an “Outside to Inside” line being used when cornering in gravel. We call this a rally late apex.
This approach squares off the corner with the intention of shortening the time the car spends cornering. Because this approach straightens the line on entry and on exit, it allows the tires to focus on one task versus dividing it up. Both the track racing line and the rally late apex line have the same intention: to straighten the road out as much as possible for forward acceleration.
On gravel we just need to be more extreme about getting the car pointed straight on the exit as soon as possible. Furthermore, by aiming to exit the corner on the inside line, if we experience any unexpected changes in grip, we have room to correct it before doing some landscaping in the woods.
Finally, we have a saying that “in rally, the only consistency is the inconsistency.” Gravel is a dynamic surface. It moves around and deforms easily compared to the static-ness of asphalt. These constant changes dramatically affect the way tires move through and grip the surface.
There’s no guarantee the grip on corner entry will be the same on corner exit, or even from one side of the car to the other. Even though you have done your recce and have your pace notes, the road will be infinitely different by the time all the competitors ahead of you have gone through it.
In stage rally, surprises are the norm. There could even be surprises left waiting on the road from other competitors cutting corners pulling new hazards into the road…or just somebody’s exhaust muffler.
The Monte Carlo rally is a great example of the wide variety of environments and conditions drivers may face. One stage alone could feature asphalt, gravel, snow, and rain. The extreme variability forces drivers to constantly adapt everything about their driving.
Because there are no laps in stage rally, you only see that corner once; and it is the first time you’re seeing that corner. You better get it right the first time, or leave yourself enough margin for error in case you don’t.
There are a plethora of other nuances between racing on asphalt versus gravel. Most need to be felt in the moment before they can truly be understood. Racing on gravel is more of an art form, like a Bob Ross painting, than a calculated science.
Luckily, if you’re not a perfectionist, you’ll always have the changing gravel as an excuse as to why you messed up that corner…Not that I have ever used that excuse on my student demos…no, never.