The next
generation Champ Car tire should be Bridgestone's F1 tire
The days of getting a Champ Car
crossed up and hangin' it out around a racetrack are gone. What we see now is more
sanitized, faster, and less entertaining. The biggest culprit are the tires.
As Champ Car tires (and Toyota Atlantic tires) moved to low-profile sidewalls the
fans were cheated out of one of the more entertaining aspects of our sport.
Today the cars follow each other like railroad cars on a railroad train. Is
the next generation Champ Car also heading for a train wreck, or will the new OWRS
regime see the light?
When you watch F1 cars you see the rear ends shift around through the turns. This gives them a much
faster look than the planted look that you get from the Champ Cars. They
appear more "on the edge" which makes them more exciting to see be it a
qualifying lap or a race stint. The give in the tires as they whip
through a turn is a racier appearance than the "on rails" look of the
Champ Cars at any speed! Let's examine why.
The low-profile current generation
"radial" tires demand that the drivers keep them at small slip angles. A bias ply
tire from the '80s made its peak cornering load at about 12 degrees slip angle
and it had a broad range where it will produce reasonable side force. A
modern radial makes its peak cornering force at about 4 degrees and the
drivers have a very small range of where it will produce peak cornering force. The
yaw angle of the car is going to end up to be about 1/2 that of the tire slip angle.
The old cars drifted around at about
5-7 degrees yaw, and the modern ones drift around at 1.5 to 2 degrees yaw. If we
were looking for one thing to point a finger at what has made motor racing less
entertaining to watch, especially for the general public, it's been the move to
wider radial tires with shorter sidewalls. Even on a radial, the narrower the
tire, the more slip angle you get and the more sidewall on the tire, the more slip
angle you get. This is probably best viewed by looking at a dirt track tire and
its high sidewalls. You never see a low profile dirt track tire.
A sprint car tire with low air pressure and a big sidewall gives you a lot of
warning when it's going to break loose, and has a large operating window. When the
current low-profile Champ Car tire gives up, it does so very abruptly and saving
it is a hell of a challenge. The best Champ Car drivers get the tire to an
impending slide, but make certain to not step over the line.
You can visibly
see the higher profile F1 tires flex under load, allowing bigger slip angles
and a larger operating window before breaking loose.
Let's back up. The reason that the tire manufacturers make tires
that run at small slip angles is because it's faster. It gives the driver a knife
edge to drive on, but if he does everything correctly, then the tire runs cooler
and doesn't have as much rolling drag in the corners (i.e. it isn't being deformed
as much and it isn't soaking up big chunks of engine power). Particularly when
there's a tire war, tire companies make a tire that has very high capabilities,
but is difficult to drive. In 1998 when F-1 first introduced grooved tires, the
sliding and drifting was a lot more. It made for a great show. As Michelin and
Bridgestone have fought each other in a tire war, that drifting and sliding has
been reduced. It's still a grooved tire, so they dance around more and do get
visibly sideways more than Champ, Atlantic, or F3000 cars.
Champ Cars (and Atlantic for that matter) aren't in a situation where a tire war
is an issue. Bridgestone knows that they can produce anything and still say they
won the Long Beach Grand Prix, or whatever race every Sunday. What they then shift
their concentration to is safety and marbles. They want to make sure that no tires
delaminates and gives them a black eye on TV, and the sanctioning bodies try to
get them to eliminate marbles, which they blame for no passing.
Both of these are valid, but in addition to these, I think they
need to produce a tire that operates at large slip angles. Take whatever slip
angle that the tires operate at right now (the manufacturer will know through
their testing) and double it. Make the tire have a broad slip angle curve and let
the cars have some serious yaw angles as they get through the corners. Who doesn't
like watching old footage of Jimmy Clark drifting around Silverstone?
Click and enlarge and notice Coulthard sawing at the wheel and the opposite
lock he puts on his F1 car. Opposite lock, big yaw and big slip angles -
racing isn't supposed to look like a railroad train
All this is easy to write, but more difficult to implement. As I said before, high
slip angles soak up big chunks of engine power. This engine power is turned into
heat inside the tire. When a tire runs hotter it is more likely to delaminate,
blister, explode, etc. Bridgestone wouldn't be interested in having any of the
above happen and neither would anyone else. One thing that hotter running tires
also lends itself to is to tire degradation through the run. Rubber has a lot of
oil in it. If you get it hot, the oil burns off and the tire chemically changes.
The hotter the tire, the quicker the oil burns and the more the tire changes
through a run.
I don't think this is a bad thing. It will make the drivers play
chess a bit more instead of trying to throw in qualifying laps for 2 hours
straight. If someone does try to run at 100% all the time, they will burn their
tires off and everyone will pass them. Passing is good for the sport.
There were rumors that OWRS had gotten Bridgestone to produce a harder tire this year,
but they were later refuted. I really think
that's the wrong way to go. So does NASCAR, who went softer this year. When tires
don't degrade through the run, the drivers do end up trying to run at qualifying
pace for the whole race. When they try this, they crash. It's just a law of
averages thing. At qualifying pace you are taking a lot of chances. Sooner or
later you're going to get it wrong. Maybe Senna, Schumacher, or Montoya could do
it, but you're talking about 3 guys over the last 20 years. These are very special
men. Even they wouldn't be able to do it every weekend and get away with it.
Getting more sidewall is going to be a sticky thing to push now, it
has to wait for the next generation Champ Cars. If you get more sidewall, then you
get less wheel. Less wheel means you have to repackage everything
inside the wheel. Smaller brake discs, smaller brake calipers, smaller
uprights, etc. From a heat management angle alone it would probably
necessitate carbon brakes.
However, with that said, I think it's not only valid, but damn near
mandatory that Champ Car adopt the higher profile F1 tires. In fact the
wheels and tires should be exactly the same as F1 so that both Michelin and
Bridgestone have something to start from for Champ Car. With the F1 size
tires we will see more movement in the rear-end of the cars. It will
also better prepare a Champ Car driver for F1 should they get the chance.
Engaging the general public and letting them see what the driver is
dealing with from their seat in the stands or on the couch is something that OWRS
really has to concentrate on. Because if we're in for another generation of
railroad car racing, they might be in for a train wreck!
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