We have talked about alignment and related issues throughout the past 10 years with a certain regularity. It's a very important part of the total setup package that you need to attain in order to win. Lately though, because of the rush toward soft front springs combined with, not big, but smaller front sway bars and stiffer rear springs, our range of motion in the entire suspension, front and rear has changed.
Because of those changes, if a team has not addressed their alignment and checked within the new range of motion, the picture might just be very different indeed. That is because most of our suspension components travel in arcs and that make their motion non-linear. As such, we can only be correct, or know what is truly happening if we check our alignment within the range of motion that the car will actually be experiencing.
Alignment is made easier today by the use of laser systems and specialized equipment.
Top teams and many manufacturers of race cars have discovered the importance of alignment. There is a long history of how alignment was established by the car builders and how that might have facilitated setup trends. There was even some manipulation of the chassis alignment to attempt to cure handling ills. Those days are mostly gone now and there is good information and many different tools available to use to establish proper alignment.
Of all of the setup parameters, including moment center location and setup balance, alignment ranks at the very beginning of the list. Why? Because when your alignment is not what it should be, nothing will compensate for it. The alignment package has a tremendous influence on the way a race car handles.
Along with the knowledge of the importance of alignment has come better equipment that we can use to check and adjust our race car so that it is aligned perfectly. The reason for the onslaught of interest in this issue is because car builders have finally bought into the importance of roll centers, setup balance, Ackermann issues, and alignment.
The manufacturers of race car parts have now included in their inventory tools that help us align our race cars more accurately and quickly. We now have available laser alignment systems and bolt on tools to facilitate our measuring processes.
The Elements of Proper Alignment
A. Toe Settings—We need to set the proper toe at the front and the rear. A set of tires that are not toed correctly will create a lot of drag, much like applying the brakes and sometimes more efficiently than the actual brakes. The standard of the circle track industry is to toe the front out 1/16- to 1/8-inch for asphalt cars and more, up to 1/2-inch, for dirt cars. The rear wheels are to be straight ahead and parallel to each other, having no toe at all.
B. Bumpsteer—Bumpsteer can alter the front wheel alignment due to incorrect angles in the tie rods or other factors. We need to check the bumpsteer characteristics for our front suspension at the range of travel we will experience going through the turns.
C. Front to Rear Tracking—The tire contact patches must track straight ahead from front to rear and, in most cases we need to line up the right side tire contact patches. Our final alignment will show the right side patches are in line with one another with the rearend being perpendicular to that line.
D. Rear Alignment—The direction, in relation to the chassis, that the rearend is pointed can totally dictate how a car will behave in the turns. For example, on turn entry, if the rearend is pointed to the right of the chassis centerline, no amount of setup tuning will prevent the car from being loose. That looseness will stay with the car throughout the turns, especially ruining the turn exit. If the rearend is pointed to the left of the centerline of the chassis, the car will be tight through the middle and off the corner.
There should never be any reason to misalign the rearend. It should always be very close to perpendicular to the centerline of the chassis and to the right side tire contact patches, which are themselves inline.
E. Ackermann—The last alignment priority, and one of the most important, is making sure you have very little Ackermann, which is the creation of additional front toe as the wheels are turned. On most 1/4- to 1/2-mile racetracks, we need very little Ackermann to make sure the wheels are tracking inline with the radius of the turn for each wheel.
Calculations show that for circle tracks with fairly large radii (much more than was used to design for our passenger cars for turning the corner at the stop sign) a very small amount of added toe is needed to properly align the front wheels to their individual radii.
Steps to Take in Aligning the Car
These represent the basic steps you take to setup for a string alignment. These lines will
There used to be only one reliable way to align a race car and that was by using a string and either measuring to the tires at hub height or at the floor by creating right triangles on the floor to measure from. That is still a viable way to do it and necessary for the lower budget race teams.
A quicker and more accurate way to align the car in all areas is by the use of a laser system. The key to maintaining accuracy in a laser system is to be able to check the tool to make sure the beam is truly tracking at right angles to, or inline with the mounting device. All of these systems allow for checking the accuracy of the laser beams. This must be done each and every time we use the tool to check alignment.
Step 1. Race Car Attitude
Note: It's important that you consider the attitude of the car as it will be on the racetrack. With the newer setups on both asphalt and dirt, the front ends are very compressed and lower. This may change many alignment parameters that may be fine at ride height. We don't race at ride height, so placing the car at the racing attitude makes perfect sense.
When considering the following procedures please take into account your cars attitude on the racetrack and introduce the proper heights before doing any alignment work. The results will more closely match the on-track alignment if you do.
This means that instead of setting the car at normal static ride height, you lower the front end to where it will be when the car is racing on the track. Measuring within the range of motion the car will be working in is the most accurate way to do this. It matters not what the alignment is when the car is sitting in the pits if it immediately assumes a different attitude leaving the pits and all through the laps to follow.