At the race, you’re unloaded and ready to go for the first practice session. After the session is over, you feel lost because the handling is way off. You make changes that should help, but in the next session, the car feels even worse. The same scenario continues for the remainder of the event, and you’re unhappy with the result. There is a good chance that one or more of the following sins is the culprit behind your situation.
Any one of these problems can be your undoing. Most racers are guilty of breaking several of these sins regularly.
- NOT CREATING A SOLID BASELINE
One key to being fast and competitive is repeatability. You just cannot repeat results if you do not know where you start. A good chassis baseline is the one recommended by your car builder or based on experience at the race track with your car. If you have the experience, create your own baseline. And best of all, if you have records from earlier races at the track you are going to, it gives you a head start. You should have the following: frame heights, crossweight percentage, rear and left side weight percentages, all four tire circumferences, tire pressure and wear, tire compound if not a spec class, fuel load, gear ratio, spring rates, bar neutralized, shock valving, toe, rear alignment, pinion angle, panhard bar height or Watt’s linkage settings and any other setting affecting the handling.
- PREPARING THE CAR AT THE TRACK
This happens too often. You run out of time or have inadequate help before a test or race, so you end up preparing the car at the track, or at least finishing the job there. It is very difficult to create a good setup at the track. It is easier and much more effective in the garage or at the shop. Track time is expensive for a test day. Wasting that time is not effective. And if you’re prepping your car at a race, forget any chance of a good result.
- NOT TAKING TIRE TEMPERATURES
Tire temperatures are your link to what goes on between the tire contact patch and the track surface. I find it difficult to make sound tuning decisions without tire temps. Tire temperatures should be taken religiously every time the car comes in after a run on the track, even after a race.
- NOT TAKING SEGMENT TIMES
Time around the track is gained in small increments. Chassis adjustments can make a car faster — or slower — around the track, but may cost time in certain areas of the racetrack. Knowing this can add to the data available for you to make sound tuning choices. The only way to accomplish this is to record times in several segments of the racetrack. You don’t need to take times in every segment on every lap, but taking segments at various points for each session will prove valuable, especially in testing.
- USING TOO MUCH CROSSWEIGHT
Crossweight, the measure of right front and left rear combined weight vs. total car weight (both with driver) is a useful tuning tool. In road racing or autocrossing situations, excessive crossweight will help handling in one direction but hurt in the other — and it hurts more one way than it helps the other way. Crossweight should be set at 50 percent and never less than 49.5 percent or more than 50.5 percent.
- NOT KEEPING RECORDS
This may be the most costly sin of all. There is just too much data to keep track of without writing everything down in an organized way. Even if you get a good setup, without records you will be unable to repeat the setup without going through the complete process all over again. The most important time to log records is back in the shop after a race. If you have a good race setup, this will tell you how to get back to the setup the next time you race at that track under similar circumstances. And if the results were not so good, at least you know you need to do something different.
- LISTENING TO TOO MUCH ADVICE
Everyone is a setup expert, or so most people would have you believe. It is imperative to achieve success that you learn enough to make your own tuning decisions within your own team. Listening to advice from others is one thing, putting it to use is another. Even if the person offering advice is very knowledgeable, that person likely does not know your situation, preferences, resources or needs. It is difficult to give advice that is useful, and most often, the person offering advice is less knowledgeable than you are, and usually only knows a couple of things that could cure your perceived problem.
In my experience, working with techs from companies supplying parts, shocks or tires is helpful. But there are pitfalls to this. The tire guy always wants to cure a problem with the tires, the shock guy with shocks. While they may be correct, often it is something other than what the representative is comfortable working with.
- NOT CREATING A GAME PLAN
Any plan is better than no plan at all. Take the time to create a game plan for each race, beginning with your realistic objectives, maintenance schedules, testing and race strategy. And remember that part of a good game plan is the flexibility to alter the plan as needed. Usually, no plan equals no result.
- NOT DETERMINING EXACTLY WHERE THE PROBLEM BEGINS
A handling problem can occur anywhere on the track. Is it corner entry, mid-turn or corner exit? Does it happen everywhere? If a problem occurs in one place, does it result in a different problem someplace else? The classic example of this is corner entry understeer that a driver overcompensates for at the exit of the corner, creating an oversteer condition. The driver says the car is oversteering, but the real problem is the corner entry push. Adjusting for the oversteer will make the problem worse.
- HAVING A SUSPENSION BIND
Suspension binds create an inconsistent handling situation. If a bind is present, it is just about impossible to tune the suspension. If the car does not respond the way you think it should to changes, check for bind in the suspension. And checking for binds should be part of your routine setup process.
- HAVING A DEAD SHOCK
A bad shock can be very difficult to feel. Check the shocks if you cannot get the chassis tuned effectively. Feel for dead spot or lack of resistance in both rebound and compression.
- TOO AGGRESSIVE SETUP FOR DRIVER EXPERIENCE
Often, the fastest setup for a given car is too aggressive for a driver without some experience. When the suspension is too stiff, especially the shock valving, it is difficult for the driver to feel what the chassis is doing. The car reacts too quickly for the driver to sense what is occurring. Softer springs and shocks, while slower for the experienced driver, may be faster for the inexperienced driver.
I have had first-hand experience with this as a co-driver in endurance races. I drove a car with a very stiff springs, to the point that we found a video frame over a bump with the rear tires off the ground slightly. The was not at all forgiving to drive near the limit and it really beat on the driver due to the harshness. The owner of the company providing the suspension was working on the crew, someone I have worked with for years. When I queried about the setup, he said the owner of the car, my co-driver, insisted on that setup because the class champion had the same setup on his car. Later, the car owner referred me to a spring rate thread on a brand-specific racing forum. There was lots of talk about spring rates, but not a single mention of wheel rates and suspension frequencies. Discussing spring rates is irrelevant. Knowing what the spring is doing at the tire-track interface is important, but determining the correct spring rated for the bumpiness of the track surface requires knowledge of the suspension frequencies. If you do not know how to calculate suspension frequencies, then find someone who does. And if your suspension manufacturer doesn’t know either, you may want to find another one.
- MAKING CORNER WEIGHT ADJUSTMENTS AT ONE CORNER ONLY
To adjust corner weight percentage, you must change frame height. Suspension geometry is designed to work best at a certain frame height. Changing the frame height can alter the suspension geometry in a negative manner. Making one big change at one corner can cause this to happen. The trick is make small changes at all four corners, or at least three corners. Instead of putting a turn in the right front, put a quarter turn in the right front and left rear, and take a quarter turn out of the left front and right rear.
- TRYING TO CURE HANDLING PROBLEMS WITH ONLY ONE ELEMENT
Any handling problem can be changed by adjusting several different parts on a car. It is ineffective to use only one or two items to affect the handling. Often, engineers, shock, tire, spring, etc., will try to cure a problem by using what they know best. This is often not the most effective way to problem solve. It is important to look at the entire system as a whole, then make changes that suit the system best and offer the most favorable compromise.
- MAKING MORE THAN ONE CHANGE AT A TIME
It is always best to make only one change at a time. Making more than one change can prove difficult to analyze. Which change helped? Did one change actually hurt?
- MOVING TOO FAR AWAY FROM RECOMMENDED FRAME HEIGHTS
This can cause binding in the suspension or at a minimum cause undesirable suspension geometry.
- INACCURACY IN MEASUREMENTS
As bad as not keeping records is in the first place, recording inaccurate measurements is as bad or worse. This can lead to all kinds of problems.
- INCONSISTENT FUEL LOAD
Changing fuel load will always be a setup and tuning problem. As fuel is burned off, handling will change. If you do not tune at a constant fuel load, your data will be inaccurate and the results misleading. No more than a two gallon fluctuation is acceptable. One gallon is a better mark.
- CREW/DRIVER COMMUNICATIONS
If the crew and/or driver is not sure of the concepts of tuning and clear about the language, all sorts of problems can occur. Everyone on the team needs to be on the same page. An example of this occurred on an Indy car team. The driver, who was not a native English speaker kept complaining about the car pushing. The crew chief kept making changes to the car, but the problem only got worse. Finally, in a fit of frustration, the driver yelled at the crew chief that the car is pushing at the rear. Luckily, the driver didn’t “push” the rear of the car into the Brickyard fence.
- DRIVER OVERDRIVNG
If a driver is over-driving the track or setup, most of the data, whether from the driver or tire temperatures will be less than accurate. Over-driving not only abuses the tires but also masks real handling problems.
- MAKING CHANGES THAT ARE TOO BIG
If a change is too big, you can cause a handling problem that is worse than the one you already have. On the other hand, a change too small can be difficult to detect by the driver or on the stop watch. Big changes would be more than two numbers on shock valving, more than 15 percent in spring or bar rate, more than 2 percent crossweight, more than a quarter inch in ride height.
- NOT UNDERSTANDING THE WHOLE SYSTEM
Understanding the whole system is very important. The key is to understand how any change affects the tire contact patch load and traction. Always thinking in terms of tire contact patch load and traction will help you focus on making the best change possible for the situation. A basic understanding of race car dynamics is very important.
- CHASING CHANGING TRACK CONDITIONS
Track conditions constantly change. The car may get faster during the day even though the lap times are slower. The track may be slowing even faster than the car is getting faster. If in doubt, return to the starting setup to see how the track has changed.
- CHASING OLD TIRES
At some point, tires get too hard to be fast. There is a point that no matter what you do , the car will not get faster. Chasing an old set of tires is ineffective.
The are many pitfalls to getting a good setup. And the problem plagues even the highest levels of racing. The 43 NASCAR Cup teams are all capable of winning a race on any given day. But only a quarter of the teams come to every race as a possible winner. Knowledge, dedication and commitment are all paramount.