Have you ever done something to your race car to try to help get it to handle better, knowing all along that the real problem probably lies somewhere else. What you did was "Crutch" the car. This term has been around for some time and it means that what you sometimes do to help the car perform may not be the best fix for the problem.

For the past thirty years or so, racers have developed some pretty ingenious ways to "crutch up" their race cars to make them handle better. Handling, in our most basic understanding of the word, can best be described as being able to drive through a turn without the car being either loose (driver looking at the infield) or tight (driver looking at the outside retaining wall). The three main areas of the turn where we might experience handling problems are: On entry to the turn; through the middle; and upon exit off the turn.

A race car setup crutch could be any change in the setup which is intended to solve a handling problem that does not make the car faster and/or causes other problems to appear at other points on the race track. We will explain how some specific crutch methods work and why racers think they need these particular crutches. Then we will work to develop more efficient ways to accomplish the same goals.

The way the driver is forced to drive the car can sometimes be a crutch. How many times have we heard a driver say that the car is loose when we can see that it appears tight on entry. What the driver is doing, but is most likely unaware of, is steering excessively trying to overcome a tight condition on entry. This definitely does create more traction in the front tires. Here is why.

A lot of research has been done on tire characteristics related to traction. Tire engineers learned that a tire will generate more traction at an increased angle of attack in the direction the car is turning. This means that the front tires will gain more traction as the wheel is turned, up to a point. When the steering gets to an excessive angle of attack, the front tires will give up all of their traction causing a severe push. But normally as the steering wheel is turned to force the front end around, the handling balance is reversed as the front traction becomes greater than the rear.

So, as the driver enters the turn, backs off the throttle and applies the brakes, he (meaning he or she) begins to turn the wheel. He must twist the steering wheel enough so that the front end will come around. If the car is actually set-up too tight, he will need to turn the wheel further than would normally be necessary in a car that is neutral in handling balance. When the driver has turned too far, the front traction exceeds the rear traction and the car begins to feel loose. This can happen so quickly that the driver will swear that the car is loose.

At about mid-turn, the car will definitely feel loose to the driver. The exit performance off the turn will suffer as the driver gets on the throttle and the car gets looser from power induce rear wheel spin. The average temperatures of the rear tires will then probably be hotter than the average of the front tires. The crew may read this as a loose condition and think the car needs to be tightened up. But they are wrong, it is already tight, and so a lot of valuable time is wasted searching for solutions to this basic problem.

A great way to quickly discover just what the handling balance really is for your car is to have the driver roll through the turn well below the maximum speed. The amount of steering input needed to just drive around the turn should be mentally noted. Then the driver should roll through the turn at near maximum speed without excessive braking or acceleration. Then note the amount of steering input. If it is more than when the car was rolled slowly through the turn, the car is setup too tight. Many drivers are very surprised at the outcome of this test. A lot of time can be saved doing this simple exercise.

Here are some reasons why the car might be set-up too tight in descending order of importance:

Rear Springs are too soft – Too soft rear springs, especially the right rear, will make a car tight.

Front Springs are too Stiff – Too stiff front springs will make the car tight by not allowing the front to roll and work with the rear.

The Panard bar is set too low – If the panard bar is too low for the springs you have chosen to race with, the rear of the car will react and want to roll more than the front causing a tight condition.

The Front Roll Center location Is Too far Right or Left of Centerline – If the front roll center is too far left, the car will roll excessively in the front and the right front tire camber will change too rapidly and loose grip. If the RC is too far right, the front end will not want to roll and the front end will not work along with the rear, much the same as having stiff springs up front.

The Cross Weight Percent is too high – This causes too much weight to be supported by the left rear and right front tire causing a tight race car.

Excess Ackerman – If the steering system creates too much Ackerman (one wheel steers more than the other) the car will have too much toe-in or toe-out in the middle of the turn. This will cause the front end to skate and push, which makes the car feel tight to the driver.

Too little Rear Stagger – Insufficient rear tire stagger will cause the car to "point" towards the outside wall on exit. There is a correct amount of rear stagger for each track based on tire diameter vs. the radius of the track vs. the track banking angle. Too little stagger will drive the car to the right at mid-turn.

Another driving crutch is the use of excess brake bias at either end of the car to help solve a handling problem. If a car is tight or loose on entry, many drivers have learned that if they make changes to the brake bias, they can improve the handling and performance at that one point on the race track. While that is possible, it can lead to problems at other sections of the turn. Using the old trial and error routine, the driver will say the car feels better on entry with the different brake bias, but now wants to work on the mid-turn handling balance which has gone bad.

So, more changes will need to be made to attempt to solve other newly created problems when those problem did not exist before. It’s not hard to see that using a Crutch to solve one problem can lead to more and more problems. Soon the team is overcome with a complicated series of handling problems while the car is getting slower and slower.

The use of the excess steering input and abnormal brake bias is an indication that other problems exist and need to be fixed. What the car needs is a better arrangement of spring rate layout, front roll center location, panard bar height, steering characteristics, weight distribution and tire stagger, all in combination. Then the last things to work with are finding the correct shock rates for optimum transition handling and the correct front tire cambers and the correct tire pressures, based on reading the tire temperatures.