Rain may be uncomfortable, but I love rain races. Anything can happen. Anything. I first discovered the joy of rain at a Trans-Am race in 1971. The Trans-Am was quite a series back in the day, mostly mustangs and camaros with the odd Dodge Challenger and a pair of AMC Javelins whose race team owner was a guy named Roger Penske. The drivers were the finest in America: Mark Donohue, Peter Revson, George Follmer--- the best of the best. Amidst all these pony cars there was one 1964 Pontiac Tempest driven by a guy named Bob Tullius. Tullius was a racer's racer, leader of the Group 44 racing team and winner of many SCCA titles, including three Trans Am titles. The Tempest belonged to the wife of a GM engineer working on Pontiac's cancelled racing program. The engineers on the team wanted to give their handiwork the acid test, so the Tempest was rebuilt for competition and handed over to Tullius for the driving and set-up chores.
Right away I rooted for it. It seemed so out of place out there compared with all those pony cars. Still, it wasn't slow, not top ten quick, but not that far off the pace. Then rain began to fall, one of those lazy summer rains that patiently pelts the place. Suddenly that out of place Tempest began to move up. Lap after lap that old gray car with factory paint began to pick off its newer, flashier competitors. Tullius got it all the way up to second, and he might have stayed there if the rain hadn't let up. As it was he ended up on the podium and was cheered every time he went by. It was a great day for underdogs, and a race I shall never forget.
Last weekend I stood on the other side of the spectator fence at Mid Ohio Sports Car Course for the Rolex Championship road racing series. My assignment was to cover at corner station 16 for the day. Sixteen is an interesting place, the second corner of a combination that leads onto the front straightaway. You're right across track from the entrance to pit lane, the finish tower is just ahead. Let me lead you through those corners. You have just come off 14, a 90 MPH left hander that is far tighter than it appears when you first see it. There's a short chute straight and then the car dips down, losing about six feet in elevation and then the circuit wheels to the right, covering around 230 degrees of a circle. That's fifteen. The track then bends left and ascends onto the front straight which runs for about an eighth mile, then another left, an 80 degree turn that's probably the fastest at Mid Ohio (An Indy car will take it at about 120).
The racing line is tricky. The course has a rise in the center, so its camber (banking) can help or hurt you depending on where you place your car, and the camber changes throughout, especially where fifteen turns left to become sixteen. Sixteen is the turn that matters most, because it leads onto a significant straight. Any racing driver will tell you that a turn that leads to a long straight is an important turn. The smarter thing to do is be careful and safe in fifteen to set yourself up for a smooth exit to sixteen. The sooner you get on the power there the quicker you go.
For amateurs that's a great strategy. Only the Grand Am is a pro race, and only talented, experienced drivers need apply. There are a lot of cars on course there, and they're breathing down your neck. You can't really afford to throw away fifteen, you must make time there too. And so the car has to deal with an at-the-limit switch between right and left plus changes in course camber. It's a tough problem. I discovered that this morning when I had to dive away from a spinning Mazda driven by Patrick Dempsey. Had to push him to get the car going again. In the rain it gets even more interesting.
First of all you face the issue of how do you set up the car. If you know it's going to rain you put on softer springs, maybe ease up a bit on the shocks. Compliance will give you traction, and you don't need so much weight control at the lower velocities rain mandates. Second you face the choice of tires. If it's raining hard the choice is obvious. Soften up the car and put on your rains. Only it wasn't raining when this race began. Sure we could all see the dark clouds moving in from the west, we could feel the wind picking up. But right now the surface is dry. And so the problems began.
In the dry you run slicks, tires completely devoid of the slightest hint of tread. As traction is a product of rubber on the road, eliminating tread increases the amount of soft goey rubber on the road, maximizing grip. The tire can be both softer and stiffer because no piece of rubber does not have rubber next to it. Tread wiggles under load, because that channel rain create weak spots. Under racing conditions treaded tires must be shaved to no more than 3/32" of tread or it will risk chunking, when overloaded pieces of rubber abruptly depart the tire.
All this means that in the dry a car on slicks will run away from one on rains. But it gets even worse. Rain tires are soft and designed to run under cool conditions. Dry tires are designed to run hot, and soften up for more grip under heat. Get rains hot and they'll chunk. So when do you change? Go too early and you might slide off. Wait too long and you'll get smoked.
One of the Krohn Racing prototypes decided on the grid to go for rains. He pitted on the pace lap, which drew a stop and go penalty, but if the rain came quick the time lost would be worth it. Unfortunately, it held out for another ten laps or so during which the car was dog slow. When the deluge came it came quickly. Cars on slicks have zero grip. An 800 hp prototype can easily be outpaced by your grandmother's buick. Cars went off right and left, and the stewards went for a full course yellow to get everyone on rains.
But even on rains it was interesting. The cars ran loose, just on the edge of swapping ends. You might not have seen it on TV, but I stood ten feet from the racing surface. Rear ends wiggled every time by, and even the smooth guys like Scott Pruett worked hard to get the power down. Cars moved up, cars moved down. Cars dove in and out of the pits seeking tire and setup changes. Plus loose cars crash. Body damage was almost normal.
And then the rain stopped. The course began to dry, but of course it dried first in the racing line. Everyone was on rains, and they began to get hot. Drivers began to look for puddles they could run through to cool their tires. Crew chiefs debated another change. Go to drys and no more stepping out, plus even more speed. But if they got off line, even a little bit, the traction would disappear. Stay on rains and risk a meltdown. Or try intermediates and be good at neither condition, but capability at both. Few chose that option though it might have been the smart one. Assuming the Rolex series cars run intermediates, which they don't.
At the end the team of Alex Gurney (son of the great Dan Gurney) and Jon Fogarty came from to end a long dry spell and get the win. They weren't the fastest team in the dry, but on this day everything came together and they won. And on this day, they really had to work for the win.