In 1956, I took over the factory '56 Chevy from Johnny Tolan on the West Coast, he recommended me to Mauri Rose, and after that I drove (on the West Coast) for Ray Nichels in a factory '57 Pontiac.

For cheap, new kids need to know about pulling the left front sway bar down to "load" the right front and left rear (some classes you have to be stock).

I write a column for Gulfport Motor Sports magazine in Gulfport, Mississippi, each month. A lot of readers read your column in CT and called me and asked about CG, RC, and MC because they run stockers and have very little money and have never been to college or had the money to go and don't understand your engineering terms.

My real reason for contacting you is to get a back order on a late 1970s CT that I lost in Hurricane Katrina. This attachment shows my stock car with wings in "open competition races." It was on the front cover of CT and was titled "Wings and Things." I emailed the back order department of CT but no answer. Can you help me?

Thanks,

—Larry Dunham

Larry,

Thanks for the verbal blast from the past. In your day, race car setup was more a seat of the pants methodology than today. We now know so much more about how the dynamics work for a race car and how to give it what it wants. It's fairly simple to understand and we try to present it in a more understandable way.

Just so you know, Circle Track magazine's very first issue (shown) was undated, but copyrighted 1982, and was released several months before regular monthly issues were printed. I have a copy of that first issue. You might be thinking of Stock Car Racing magazine which was in print longer than CT.

Flat Upper Control Arm Angles

I'm sure I'm missing something so I have to ask a question to find out where I'm messed up. In a couple recent issues of Circle Track you have commented on the "flat angle upper control arm geometry" you've seen on some Modifieds and how it will cause severe camber loss (positive camber) in the right front tire.

As I look at this suspension arrangement and the arc that the upper control arm must follow when moving up or down it appears to me that it should add negative camber to the wheel as it moves. As the upper control arm moves up and down its arc effectively shortens the control arm length, thereby pulling the top of the tire toward the chassis of the car.

Perhaps the suspension isn't moving enough to cause the effect I think I see (I'm not sure), but if you could set me straight I would appreciate it. By the way, I'm not a circle track racer, only an observer with a desire to know how things work.

—Ron Jacobs

Ron,

The problem with the way you are looking at this is you're only seeing half the picture. I love this question because lots of "real" racers get this wrong. The chassis basically dives and rolls in the turns. It's true that wheel movement in bump causes camber gain in the right front, but chassis roll causes camber loss in the right front.

To better visualize this, imagine only rolling the chassis as if it were on a rotisserie. Every component on the car assumes a new angle including the wheels. So if we roll the chassis 5 degrees clockwise, we change the right front wheel camber by 5 degrees in the positive direction. This is similar to what happens on the racetrack.

The degree of each for chassis dive and chassis roll determines the actual tire camber gain or loss and each different suspension design will result in a different camber change characteristic.

In order to correctly measure and evaluate camber change, we need to include the effects of both chassis dive and chassis roll. Only then can we know how the tire's camber relates to the track surface. And the tool for doing this is to use a computerized software program where you can enter the chassis dive and roll amounts to give you your camber change.