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Trackside Wheel Alignment - Tech Talk

Want to adjust your car’s wheel alignment for better handling at the track? Here’s how we did it for next issue’s cover story.

David Pratte
Feb 4, 2013 SHARE
Modp 1301 01+trackside wheel alignment+honda civici si Photo 1/5   |   Trackside Wheel Alignment - Tech Talk

As any experienced racer will tell you, getting your car’s wheel alignment dialed in for maximum cornering grip is a key component of overall track car setup. Having your car professionally aligned on a 3D laser alignment rack is never a bad idea, but a lot of alignment shops don’t like working on lowered race-prepared vehicles, nor do they like using alignment settings outside the manufacturer’s recommendations.

So at the very least you need to find yourself a race shop that knows how to do a performance-oriented alignment on a modified car (which often has camber plates or camber adjustable arms added to the mix). But if you’re like us and want to experiment with different wheel alignment settings while at the racetrack, then you need to learn how to adjust camber and toe and to do so in a controlled and measurable way.

Modp 1301 02+trackside wheel alignment+string box Photo 2/5   |   A string box is a great DIY tool to have at your disposal, since it allows you to measure toe alignment for each wheel separately (by measuring the distance from the string to the leading and trailing side of the tire).

We recently put our trackside alignment skills to the test, since we installed KW Variant 3 coilovers at the track and needed to be able to adjust wheel alignment for the lower ride heights we set them at. Keep in mind that when you lower a car, its wheel alignment changes, plus we wanted to dial in a more track-oriented alignment to help the car perform optimally around the racetrack.

To adjust alignment accurately, we brought along a few tools you should consider adding to your track-day toolbox. First out of the trunk was a digital camber gauge, which cost about $200 and is really just a fancy level with an arm at each end that allows you to hold the tool flush against the top and bottom lip of the wheel. The digital inclinometer attached to the straight edge of the level gives you a camber readout in degrees, and in our experience, these are quite accurate as long as the car is parked on a level surface (some higher-end camber gauges correct for the angle of the surface, but for best results, always try to do your alignments on a flat surface).

Since the KW V3 front struts for the Civic Si have slotted strut boltholes that allow for some camber adjustment, we maxed them out for as much negative camber as we could with the assumption that we’d still be well within reasonable specs for a race alignment (more negative camber allowing the car to use more of the contact patch while cornering).

By using a digital camber gauge, we could then test that assumption, and both front and rear camber were at street-friendly levels but were quite a bit more aggressive than stock. With camber plates up front and camber-adjustable arms out back we would have had a lot more leeway to experiment with camber settings, the Civic in particular being known to benefit from a lot of rear camber as a way of helping the car rotate in the corners. Take a close look at some pictures of Compass360 Racing’s ninth-gen Civic Si SCCA World Challenge race cars, and you’ll see what I mean about aggressive rear camber.

Modp 1301 03+trackside wheel alignment+camber gauge Photo 3/5   |   Used in conjunction with a tire pyrometer, a camber gauge will help you accurately dial in wheel camber for maximum tire grip in the corners.

That said, it should be emphasized that camber is best used as a way of maximizing tire grip rather than altering the front/rear handling balance of the vehicle. The best way to do this is by using a probe-type tire pyrometer to measure tire temperatures when adjusting camber. What you want to aim for is tire temps in the optimum operating range for the tire (which for high-performance street tires and race tires is generally in the 160-200F range), but with temps about 10-20F higher on the inside third of the contact patch than on the middle third and outer third. Many professional race teams and tire manufacturers have proven that this type of temperature spread across the contact patch delivers the best tire performance.

Where we had greater alignment freedom was with toe settings. Normally I like to set up my track cars with some toe-out up front, as a way of providing 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 set up, and what type of handling balance you’re aiming for. Obviously wheel alignment, particularly toe settings, are going to be wildly different on a FWD grip/race car than on a RWD drift car.

Measuring total front and rear toe is quickly and easily achieved with a set of toe plates and a couple of measuring tapes. The toe plates give you a nice stable and consistent point to measure from. These can be found online for less than $60, and as long as you know that the left and right side toe settings are equal, then measuring toe across the front and rear axle this way will give you good results. Just make sure to change toe on each side of the car in equal amounts, so if you want to dial in 1/4 inch of total front toe-out, adjust each side by 1/8 inch. This way your steering wheel will remain on center and the car won’t pull to the left or right when accelerating. Front toe is easily adjusted via the tie rods, and rear toe is usually adjusted via an eccentric nut that changes the position of the rear link, so all you need is a couple of wrenches and Bob’s your uncle.

Modp 1301 04+trackside wheel alignment+toe plates Photo 4/5   |   Toe plates and a couple of tape measures will allow you to quickly and easily check front and rear toe alignment as you make toe adjustments in pursuit of your perfect setup.

As you’ll read in the next issue, we didn’t have to do anything exciting with the FR-S’ alignment, since the car’s handling was absolutely perfect when using KW’s recommended ride height and shock damper settings. We didn’t have to touch the car after the installation, which just goes to show how inherently good its design is and how well engineered the KW coilovers are. The Civic provided a bit more of a challenge, as FWD cars usually do, so to induce some rotation, we went with aggressive rear toe-out, as well as a fair bit of front toe-out. It took a little effort to get the Civic’s alignment specs dialed in (we even went to the trouble of setting up a string box to measure toe at each wheel individually, for some added precision), but it was really rewarding to make these changes and feel the back end swinging around in a gradual and very controllable way, just the way we like our FWD cars to handle at a racetrack.

Point being, wheel alignment isn’t something you have to “set and forget,” nor should you think of it as something that should only be done on an expensive 3D laser alignment rig. With the basic tools we used, you, too, can quickly and easily record and adjust your alignment settings in the never-ending pursuit of more grip and speed. Pro race teams have unique alignment settings for each track they race at, so don’t be afraid to do the same.

Send your letters to PlanetDave@me.com

Modp 1301 05+trackside wheel alignment+honda civic front fascia Photo 5/5   |   Toe plates and a couple of tape measures will allow you to quickly and easily check front and rear toe alignment as you make toe adjustments in pursuit of your perfect setup.
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Longacre Racing
Monroe, WA 98272
800-423-3110
www.longacreracing.com
By David Pratte
216 Articles

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