Aligning the Car
Now that we have checked and adjusted our car for Ackermann and rear steer, the final step is to align the car. This includes the front toe settings and rear wheel alignment, which involves rear squaring and right-side tire contact patch alignment.

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 or parallel to the mounting device. This must be done each and every time we use the tool to check alignment. The following are the steps we use to align the car:

Step 1, Wheel Runout Check
Check both the front wheels and the rear wheels for runout. This means that as the wheel rotates, the outer edge of the tire may wobble slightly. We must compensate for this slight distortion by finding the extreme high spot at a point equal in height to the hub height.

We can simply use a jackstand to hold the measuring tape steady and then rotate the tire noting the distance from the stand. Once we locate the high point (seen as the least distance to the offset), we mark it with an arrow and then rotate the tire (be it front or rear) so the arrow is at the top, pointing straight up.

Now, check the toe at the rearend. Use toe plates or toe bars for the "analog" method and the laser systems for a more accurate assessment. Even small amounts of toe-in or toe-out are not acceptable. Be careful how each person holds the toe plates so that the measurements are consistent. Do the measurement several times to ensure accuracy and repeatability.

When using the laser systems that attach to the hubs, remember to thoroughly clean the surface of the hub and make sure there are no protruding threads from the bolt holes. It's recommended that you go over the hub surface with a flat file to eliminate any bulges or protruding edges of metal that would cause the laser to not be aligned properly.

Follow the manufacturer's recommendations for setting up the laser systems. Remember that the accuracy of the measurements is directly related to how closely you follow the directions and how carefully you read the system. There's a logical progression to alignment and each company has put a lot of thought into the methods. The end results, if properly applied, will be the same.

Step 2, System to Frame Setup
Once the rear wheels have been toed straight ahead, square the laser system to the frame. Most car builders will align at least one framerail parallel to the intended centerline of the chassis. It may be located on the right side or as the weight box on the left side next to the driver. You can also align the laser system to the centers between the front and rear clip rails closest to the main framerails.

For the analog method, this setup can also be done using strings. We will set up a "box" with strings on each side and at the front and rear. We use plumb bobs to make marks on the floor off the outsides of the framerails or the front and rear clip rails. For perimeter cars, or ones with no offset in the chassis, we can split the measurement between the front and rear clip rails closest to the center section to find the centerline of the chassis.

For offset chassis, we'll be able to use a straight rail, or we could again split the clip rails. Measuring between the marks, we can split the distance in half and place a mark at the halfway point, or at the centerline of the car.