No matter how long you have been racing, I am most certain you have encountered a weather forecast that looked grim. Don’t debate on whether to get out there. Do yourself a favor and go for it! If you prepare correctly and have the right mindset, driving in the rain can be more fun than driving in the dry. I myself do a rain dance the week before a race. Rain separates the mentally strong from the weak and can be a huge advantage if you know how to drive in wet conditions. From the outside, it can be intimidating if you don’t know much about driving in wet conditions, but it is simpler than you think. I will give some pointers on how to set up your car and how to get the most out of the car in wet conditions.
My First Time
My first time driving in the rain was back in 2004. I was 9 years old and racing karts. I always got so nervous right before a race that I was on the verge of losing my cookies, and many times I did. Don’t drink a whole bottle of red Gatorade if you’re nervous. The aftermath creates quite a scene.
That day, I had absolutely no clue what to do in the rain and I was terrified. I spun many times during the race and I didn’t know how to navigate the surface changes. We were beginners at this, but no one explained how to get around the track in those conditions. I thought you just did the same thing as in the dry. When I look back, I wish I were given some pointers on what to do and what not to do before trying to drive around the track in the rain. In the following wet race, I asked for advice, and having that tidbit of knowledge drastically eased my mind. That time I never spun, had a blast, and I even lapped third place! From then on out, I prayed it would rain every race.
What’s the Rain Line?
Of course karts and cars are completely different, but the fundamentals of where you drive on the track are the same. The key to driving in the wet is simply knowing where to find grip. Most of the time, the grip is not on the normal racing line, or “dry line.” Since there is typically only one line through a corner in the dry, that line essentially gets “carved” into the track. The asphalt gets polished the more it is driven on as rubber fills in the gaps. When rain then falls, it stands on top of the asphalt instead of falling into the little cracks. It is simple to identify where the track is polished because the dry line will look shiny when wet due to the standing water on top of the asphalt. When driving on a wet track, you want to be just outside the dry line where there is less standing water. Less standing water means more grip, which means more speed. You may be thinking, what if the track is freshly paved? Then the normal line has yet to be “carved” into the track. This means you can drive closer to the dry line, since the grip is similar at the apex because it is slightly wider. The older the track, the wider you’ll have you be off the apex.
The Sweet Spot
The tricky part about driving in the wet is finding the sweet spot of maximizing speed and being just wide enough to find grip without being unnecessarily wide and losing time. I could drive all the way out on the edge of the track where there is loads of grip, but I would then travel a further distance and would lose time. Using tools such as a predictive lap timer can help you find the sweet spot of not being too wide, but also not too tight. Different types of treaded tires will affect how tight or wide you can be through the corner as well. A summer street tire can help you develop and refine your skills, because it makes the difference between the rain line and dry line more drastic. Compare that with proper racing rain tire like a Hoosier H2O or the new BFGoodrich Global Mazda MX-5 cup rain tire — essentially a relabeled Michelin Touring Car rain tire — are perfect examples of amazing rain tires that can help reduce the radius of the corner. The summer tire makes it harder to find that sweet spot, but in the end, it will make you a much better driver when you switch to those race-purpose rain tires.
Not only do you change how far off the apex you go, but also where you brake. I am not talking about distance, I am talking about where you place your car on the track. You do not want to be on the normal braking line because, just like through the corner, the asphalt will be polished at the entry and will hinder your ability to stop the car. I sidestep the brake zones just slightly and brake diagonally to eventually cross over the dry line at the turn in point. The braking point will be a little earlier, but by not as much as you think. I also do not turn in at the dry turn point, but wait just a car length longer because that’s where the grip will be. If you turn in at your normal point, you will understeer. Then eventually your front tires will find grip first as you go wide of the apex and cause you to go into a snap-oversteer situation. Be patient with your turn-in point and experiment at slightly slower speeds to find the grip at turn-in.
Getting Off The Corner
We have talked about the midcorner line and braking line, but what about coming off the corner? There are two ways of doing this: carrying a wide line all the way through the corner, or late-apexing the corner. Both ways can lead to similar times, but given a certain corner and car, one can prevail over the other. Taking a wider line allows you to put power down earlier in the corner. However, once you intersect the dry line on the exit, you must be careful with how much steering input you have and manage wheel spin. Driving through the corner with a late apex allows you to cross over the dry line earlier, putting you on the inside of the dry line at the exit, meaning you to commit to power all at once since you don’t have to worry about losing grip when under power on the exit. Pick your poison and see which works for each corner. Be mindful when you are on the dry line. It can be like black ice, so be gentle with your inputs. There can be combinations of this given certain corners and tracks, so I suggest doing a bit of research beforehand because there can be some abnormal tricks to some corners.
Things to Look For
There are a few things to look for when analyzing a track for the best rain line. Pay attention to how new the track is. If it’s less than a year old, the wet line won’t be very aggressive. If its older than that, chances are you will have to experiment with the wet line more. Other things to look for are surface changes.
Concrete will have less grip in most cases and any patches of concrete are to be avoided, such as at the old Watkins Glen. Another type of surface is sealer, which Mid-Ohio is known for. Those who have driven Mid-Ohio can attest to how slippery these patches of sealer are when wet. One type of surface change that can really only be seen from a track walk, is dark asphalt with a black sealer on top of it. Road America has this in corners 5, 6, 8, 11 and 14. This sealer goes most the way across the track, but it arcs into the corner from the turn in point and arcs away after the apex. The line I chose is to turn in from the middle of the road and stay inside the sealer all the way to the apex, then come off the corner tight as well, which allows you to roll good speed in and put the power down.
What about curbs? A general rule of thumb is any wet paint is something you don’t want to touch. The only time you can put your wheels on an apex curb is if you intend to coast over the curb with no power. With good rain tires and a new track you might be getting to the curbs as well, but like I said, being on power is a no-no when on any kind of paint. Track out curbs are to be avoided at all costs.
Using Your Inputs Under the Limit to go Over the Limit
One way to safely analyze how close you are to the limit of adhesion is to quickly add steering input and take it right back out, as if to induce understeer while on partial throttle. If the car reacts with no drama, you are well under the limit. When you get close to the limit of adhesion, this action will start to induce understeer and/or oversteer. This can help you feel the level of grip and therefore help judge the amount of speed you can carry into the corner next time around the track.
Limiting wheel spin coming off the corner is also critical. The throttle pedal also can be used as a way to help you find the limit of adhesion. Giving small quick bursts of power can teach you where that limit is. Your goal is to basically upset the car in a controlled way to help you understand the grip level. Once you understand the grip level, you then want to smooth your inputs to keep the car on the edge without upset — at least in a perfect world.
The best advice I can give is to take advantage of test days in the wet to try different lines to understand why some work and others don’t. If you are just starting out and aren’t comfortable being sideways, I would highly suggest experimenting with sliding the car in low-speed corners. If you get comfortable doing that, the little “moments” of oversteer at higher speeds seem to stop becoming “moments of terror.” This, in return, gives you more confidence to push just a little bit harder. This actually can be same for dry as well, but is much more easily implemented in wet conditions as the car moves around much more easily.
Setting up the car for the wet? In some cases it’s not necessary at all, but it all depends on the car, track and driver. I’ve driven both dry and wet setups to identical lap times. The wet setup essentially sets the car to understeer more and put down power better, whereas the dry setup will turn better in the center, but you have to be extra careful with your right foot. Both setups can be driven to the same time if you have the confidence in your ability and patience with the throttle. However, there are times when a stable car is crucial and a wet setup is completely necessary. This goes for cars that are not forgiving and have a lot of weight in the rear with a lot of power. Once that rear starts going, it can be hard to stop it.
Typical trackside adjustments to help with stabilizing the car include disconnecting the rear sway bar and making the dampers more compliant. More aggressive changes could go as far as raising the whole car and dropping the spring rates around the entire car with a slightly softer spring in the rear. This is all in an effort get as much mechanical grip as possible. Tire pressures typically run higher and you can use the recommended pressure from the manufacture as a starting point.
Racing in The Wet
Now that we have touched on driving in the wet and setting the car up for the wet, lets talk about something that can help you race in the wet: visibility. Visibility is crucial to going fast. If you can’t see where you are going, it doesn’t inspire much confidence.
In a situation where you’re buried in the pack on a start and the spray is out of this world, visibility is always an issue and all the Rain-X in the world can’t save you. The best thing you can do is use references off to the side of the track and pay attention to the brake lights in front of you. Being cautious is OK! You don’t need to be full throttle all the way up until your braking point. You can lift early in preparation for the corner ahead. I guarantee everyone else will be doing the same thing. Another thing that can help with visibility is anti-fog. If you have a defroster in the car, great. For those who don’t, anti-fog as well as a backup squeegee with a rag on it —within arm’s-reach — is a great help. In all the years I have raced, antifog — even on the inside of visors for open wheel guys — and defrosters have served me well, and I have never had to use a squeegee.
To conclude, driving in the wet really isn’t scary if you know how to approach it. It can be a great way for you to learn car control since speeds are slower and can prove to be a great advantage once you get it down. In the end, I hope this makes you more excited to get out to the track and experiment in the wet.
Rain Race Videos
Here are a few rain races from different NASA regions.