The traditional dry racing line is all about maximising corner speeds, through driving the biggest radius possible, to get the highest top speeds on the straights. While driving in the rain, all that can go out the window and you must drive for maximum traction- the dry line may not yeild the fastest lap times.

This can at times be a combination of the tradition dry line with the largest radius for corners, or even be a line which requires taking the dry part of the track with the most grip- this may mean you drive around the outside of the corner. Add to the equation that the race track conditions can normall be constantly changing, with the the track either getting wetter or drying out. What might of been the fastest lap possible on one lap, could easily change the following lap.





Lets have a closer look at why the traditional dry line may not always be the best path to take while driving in the rain.





Road Camber:

On the track were camber or banking towards the apex of the corner is present, two things tend to happen which affect the rain racing line.





1. Due to the fact that the apex is the lowest part of the track in this layout, water collects at this part of the circuit and tends to create deep puddles. Depending on the tyre selection and the actual puddle depth or standing water levels, driving through the normal apex could result in a total loss of tradition in extreme cases. When this does happen, it does not matter how large a radius you take to negotiate a corner, all cornering forces and traction may be zero. This is caused by aquaplanning, where water builds up under the tyres contact patch, separation the rubber compounds from the track surface- resulting in a total loss of traction and directional control. In this situation you will slide across the water until traction is regained, modifying your driving line will yield better lap times.





2. The outside of the track will be the opposite of the first scenario, with corners with banking and camber towards the apex. Water will tend to run away from the outside of the track and towards the apex, being helped by the camber and banking. This means that the outside of the corner (rim), will most likely yield the best traction potential and fastest line through the corner.





The two points we have just looked at for driving in the rain with cambered and banked apex´s, are not the definitive rules for wet weather conditions, it is used as an illustration how the dry line may not always be the best line all the time. As previously mentioned before, the track conditions will most likely be constantly changing, depending on weather conditions. There maybe times when the fastest lap times possible will be in between the tradition dry line at the apex of the corner (inside of track) and around the outside of the track. Or with a quickly drying out track, with full wet weather tyres fitted, you would want to drive towards wetter parts of the track in order to cool the tyres.





Road Wear Rates:

The traditional dry racing line will have been driven over more than other parts of the race track. This in dry weather conditions can be extremely advantageous for traction, as more and more rubber from traffic is layed done, layer upon layer, you get the effect of the track rubbering in. As the race progresses this "rubbering in" continues to aid traction, with the traffic on the racing line depositing even more rubber on the track surface. This has an effect of filling in the small track irregularities with the rubber deposits, creating an ideal environment for rubber to work in. This is great for the dry but very problematic for racing in the rain.

When it begins to rain, all the "rubbering in" starts to get washed away, nullifies the advantage seen with dry runs. This leaves a highly polished track surface underneath on the traditional dry racing line, compared to other areas of the track which are subjected to less wear. As there are higher wear rates on parts of the track on the dry racing line, when it rains water tends to just stand there and not drain away, as seen on more porous parts of the track. This combined with all the oil, anti-freeze and other track containments washed off the track, now tends to settle where the water does, creating a big problem for grip levels. Effectively causing the traditional racing to become undrivable.

Generally speaking darker or duller areas of the race track in the rain, tend to reward the driver with more grip. They have been less worn down than other parts of the track and are more porous. Lighter or more polished parts of the track, tend to be more slippery and could retain deeper standing water. The outside of the race track, or off dry line sections, tend to be more porous and water can easily drain off them, also there tends to be less track containments present, when it does start raining.





Rain Corner Driving Technique:

When driving in the dry, we use the tachometer to help us see corner exit speeds, with different line applications. Ultimately which ever racing line we take which yields the best corner exit speeds, is the one to take. This is no different in the rain and due to the nature of constantly changing track conditions, if the corner exit speeds start to change on your chosen racing line- it is now time to modify your driving style. Grip levels on the track will be changing and it is time to start experimenting with the now new track conditions.





Outside Corner Driving Line:

Especially effective on long sweeper corners or hairpins, with lots of cornering forces required or a longer time period. As cornering forces on the dry line are reduced, even if the corner is taken at a bigger radius, the more time spent cornering at higher speed results in reduced lap times. The outside of the track is grippier and lets the tyres work with more grip to generate lateral cornering forces, reducing time spend negotiating the corner. Higher corner exit speeds translate into more top speed on the straights, reducing overall lap times.





Late Corner Turn-In:

With shorter and tighter corners, the advantages of the outside corner line driving technique in the rain, becomes less effective. This is because the amount of time spent cornering is greatly reduced. In this situation it would be better to utilise available grip for braking and acceleration to maximise lap times with the lower and shorter time spent cornering. By braking slightly later and harder, corner turn-in speeds are reduced, meaning we can straighten the car up quicker. This gives the advantage of earlier throttle application, in a more aggressive nature, as all grip can be used for acceleration once the braking and cornering is completed. This technique realises on the driver turing the short and tight corners into a series of braking and acceleration zones, with slow speed turning linking it all altogether.

Both of the two rain driving techniques explored with involve crossing the tradition dry racing line at some point. Smooth progressive steering, braking and throttle application is required to minimise the potential of spinning out in this situation. It is also critical to take into account racetrack surface materials and overall layout into the equation. You rain driving technique could may well be a combination of "outside line" and "late turn-in", also combined with the traditional dry line. Depending on how the weather conditions continue to have an effect on track conditions, this can change from corner to corner and even be different on each individual lap.





Rain Straights, Driving Technique:

While driving on the straights in the rain, it is possible to get wheelspin, even in low powered cars. The traditional dry line will not do in this situation, as you might of guessed adjustment of your driving style might be in order. It is always best to drive on the driest part of the track, if even if it does put you out of position for the pending corner. This might not seem a logical manner to go raining in the rain, but we will see why this is the case.

Hitting standing water at speed, has a dramatic braking effect on the car, let alone the possibility of aqua-planning. If one tyre, or side of the car is subjected to this situation (hitting a puddle), a spin is the most likely outcome, especially at greater speeds. If you have no choice and have to hit standing water, it is best to approach it square on if possible. That way you may skim over the surface water and have a chance of pointing in the right direction, having driven through it.





Rain and the Braking Zone:

Traditional braking zones are most likely to be different when racing in the rain. Again weather conditions, track surface materials and race track layout will determine this.

It comes down down to the fact that the racing line in the dry will again have the highest wear rates. In the braking zone this shows itself as ruts in the race track, which tend to be filled with standing water in the rain. Much like the dry line apex when it is raining. Ruts filled with water in the braking zone will greatly affect the racecars ability to brake effectively. If you can adjust your driving style to position your tyres on the crown of the braking zone ruts, and not in the troughs as they will further limit braking force potential.





Overtaking in the Rain:

Overtaking in the rain is especially difficult, but is not impossible. Not all drivers are the same and some are less effective at reading ever changing track conditions, especially with a evolving racetrack. You can use this knowledge to your advantage, keep your driving style as cool, smooth and consistent as possible. Patience is definitely a virtue in this situation and can mean the difference from finishing the race or not.

Caution must be taken when even attempting to drive off the driest line, grip will be greatly reduced and this path will pose greater risk. Spinning out in the rain is a real risk, especially of the wet line, putting pressure on the car ahead can be a good tactic to use. The driver ahead could be forced into making a mistake, in the heat of the moment, opening up the opportunity to overtake and gain that much awaited grid place.