The Moment Center controls the dynamics of the front suspension in a double-A arm suspensi
4. Moment Center Challenges
The growth of information about the front moment center during the last several years has helped us to understand the way in which this invisible point controls the front dynamics of our race car. We have defined exactly what the MC does and where it should be located
The primary reason why two seemingly identical cars will handle differently can often be traced to a front MC that is in a different location from car to car. Knowing the role of the MCs and being willing to make changes so that our MCs are in the right position is one of the very first and most important steps we take to achieve the total handling package.
Front wheel camber change is influenced by both chassis dive and chassis roll. It is the c
5. Camber Challenges
Using excessive or deficient camber in either of the front wheels can be one of those racing crutches that can mask other problems. This usually means that the car has a setup and/or geometry design problem that is causing incorrect weight transfer or incorrect camber change during cornering.
The most useful definition of Camber Change is the deviation from the static camber that happens when the car enters and negotiates a turn and goes through a combination of dive and roll of the chassis. The number of degrees of camber that the front wheels lose or gain relative to the racing surface from static (down the straightaway) to dynamic (in the middle of the turns) chassis attitude is true camber change.
If we try to determine the amount of camber change by bumping the wheel with the car at static ride height, we will not see a true picture of our camber change characteristics. The true camber change relative to the racing surface, which is all the car knows, results from a combination of roll effect and dive effect measured together in combination.
It’s a good idea to buy or borrow a good quality spring rating fixture so you can accurate
6. Spring Rate Challenges
The primary components used to set up a stock car are the springs. When we have chosen the correct spring rates, in conjunction with well designed Moment Centers and weight distribution, then we get what we want—a balanced and fast race car.
All too often we crutch the car using inappropriate spring rates and weight distribution that will serve to provide neutral handling, but not yield the desired result of consistency.
The very first thing to consider when talking about springs is, what is the exact spring rate at each corner of your car. You must test each spring and do it in the proper way. You need to know the spring rate of your springs at the ride height and range that they will be working in the car.
Make sure of your spring rates, replace bent or fatigued springs, and always know your wheel rates when altering the mounting points or transferring the setup from one car to another. The car basically rides on four springs and the more we know about how they work in our cars, the more accurately we can develop a winning setup.
7. Shock Challenges
Shock selection can enhance or ruin a good setup. We should never try to solve basic setup problems with odd selections of shocks. What we have learned over the past decade is that using shocks to overcome mid-turn handling problems can be frustrating and futile.
Solve your setup problems first before experimenting with shocks. Never crutch a bad setup. Most shock technicians will tell you to put standard rate shocks on the four corners until the setup is sorted out. Then make changes to one corner at a time to see and feel the results. The most important task is to make the driver more comfortable and that will translate into faster lap times.
And, shocks should work in conjunction with the spring rates you have. If you are running on bumps, find the spring rate for the bump and use a shock that will work with that spring rate if that is what the car will use through the turns.