If you know toe is split evenly across each axle beforehand, then using toe plates as described above is an excellent way to measure and track changes. And since toe is an effective way to adjust turn-in response and handling balance, I find myself using my toe plates at the track far more often than my camber gauge. To check individual toe at each wheel, you need to setup a string box, where you run a string down both sides of the car along the horizontal certerinline of the wheels and an equal distance from the centre point of each wheel. You can buy a fancy string box setup like GMG is using in that Porsche pic from earlier in the story, or you can use some jack stands, a couple of pieces of metal tubing (held to the stands with vice grips or clamps) with a hole drilled in each end, and a piece of string attaching them like I do.
You must, however, factor in any difference in front and rear track width to ensure the box is square, otherwise you’ll get skewed measurements. So if the rear track width is an inch narrower than the front, for example, then you need to compensate for that by setting the string a 1/2” farther from the centre of the rear wheels.
Once you’ve got your string box nicely squared and levelled, you can take measurements from the front and rear of the tire out to the string, the same way you would with toe plates, to see what the toe is at each wheel individually. Now you’ve got the ability to set toe separately at each corner of the car, or correct front and rear total toe such that it’s split evenly from side to side (especially important on the front axle, since uneven front toe can cause the car to pull to one side under acceleration). Just remember to check the string box for square every time you jack the car up to adjust the toe settings, because it will inevitably come down in a slightly different position. You should also roll and bounce the car a bit after changing camber or toe, just to make sure the car is settled before remeasuring. Also check to make sure the front wheels are pointed straight ahead. It can be rather laborious the first time you do a DIY alignment, with lots of setting up and re-setting up of the string box as you sneak up on the exact settings you’re trying to dial in. I’ve spent hours adjusting the alignment in my garage to get it just right, but it’s a satisfying feeling when you do finally get it dialled in and you did it yourself. You’ll get faster and more efficient at the process once you’ve spent some time at it.
Front toe is adjusted at the tie rods by loosening the jam nut and then turning the rod within the threaded rod end (which is connected the the hub/knuckle via a balljoint or heimjoint) to either lengthen or shorten it. It’s useful to measure the length of the tie rod on each side of the car, since this can tell you if you have more or less toe or one side or the other, plus it gives you a reference point to measure the amount of change you make from the starting point.
On the rear-wheel drive Japanese cars I’m accustomed to working on, both rear camber and rear toe are adjusted via eccentric bolts that anchor the control arms to the chassis. By rotating these eccentric (egg-shaped) bolts, the arms position relative to the chassis is changed such that either camber or toe is adjusted in the process. These bolts often have degrees marked on their flange surface, which makes it easier to see how much you’ve changed camber or toe by. On FWD Hondas, on the other hand, rear toe is adjusted by moving the anchoring point of the toe-arm, while camber is adjusted by installing an aftermarket upper compensator arm that you can physically lengthen or shorten, much like the tie rods are adjusted on the front end of the car. Point being, familiarize yourself with how camber and toe are adjusted on your car as a first step to doing a DIY alignment, and spray those jam nuts and eccentric bolts with some penetrating oil (PB Blaster or similar) because these suckers have a tendency to rust and seize up over time.
Normally I like to setup my track cars with a bit of toe-out up front as a way of encouraging quicker turn-in response. For rear toe settings I generally like a bit of toe-out on FWD and AWD cars to help the rear rotate and follow the front end, while on RWD cars I often end up with a touch of toe-in for some added mid-corner rear stability. But how you dial in your toe settings is going to depend on your driving style, how the rest of your suspension is setup, and what type of handling balance you’re aiming for. Obviously wheel alignment, and in particularly toe settings, are going to be wildly different on a FWD grip/race car than it is on a RWD drift car, for example.
We usually have a pretty good idea of where to start with our alignment settings, based on years of experience of setting up cars for the race track, but every car is a little different, so do try to get in the habit of collecting tire temp data and monitoring tire wear patterns, both of which will guide you in terms of alignment changes that may benefit the car’s grip level and handling characteristics. From a pure performance standpoint, wheel alignment is really all about getting the tires working their best, but sometimes there are reasons to use alignment settings to adjust handling balance or change turn-in characteristics even if it means compromising tire performance slightly. Don’t be afraid to experiment with wheel alignment, as its a powerful tuning tool that really can be easily implemented with the right set of tools and the willingness to use them.