When it comes to working on classic cars, many feel vehicle alignment is best left to the professionals. That’s a valid assumption, as DIY car alignment is considered an oxymoron. Alignment shops have very specialized and expensive tools to get the job done correctly. Unfortunately, many alignment shops are big-chain facilities that typically have no idea what specs are needed when aligning a first-gen Camaro, early Nova, or even a late-‘70s car or truck. Since finding an old-school alignment shop is getting harder and harder, why not do it yourself?
I ran into this very situation when I replaced an upper ball joint in my Cheyenne. I knew the truck would need to have the front end aligned after the job was done, and I actually have some old school caster/camber gauges in my garage. But, that is not an option for many enthusiasts. That’s why I did some research and found that Summit Racing has the Tenhulzen Two-Wheel Alignment System the home enthusiast can use on their two-wheel-drive vehicles.
Common Starting Points For Proper Alignment
Below are suggested settings that are dependent on your driving preferences. These are just starting points. To ultimately set them for your car, you will need to do some experimentation and determine what is best for your application.
USE CAMBER CASTER TOE
Touring -0.25 to -0.5 Deg 2.5 to 5.0 Deg 0 to 3/16-inch IN
Autocross -0.5 to -1.0 Deg 2.5 to 5.0 Deg 1/8-inch Out to 0
Road Racing -0.5 to -2.0 Deg 2.0 to 7.0 Deg 0 to 3/16-inch IN
If you are planning to get one of these relatively inexpensive alignment kits yourself, I personally think it’s a good investment. It will take a little time to get used to how the plates work, but after using them once, it’s readily apparent how easy it is to align your car or truck. While most gearheads understand the basics of what is required to align a car, when it comes to physically setting those alignment specs, some confusion still makes many nervous.
There are a set of standard-alignment specs assigned to every vehicle from the factory. The actual specs required for a particular car, depends on how that car is ultimately used. For instance, cars that see normal highway use can follow factory guidelines. If you plan on racing into corners, you’ll probably want to customize your alignment. Again, can a big-chain store understand what your car needs?
What Needs To Be Adjusted?
There are three factors which affect a vehicle’s alignment: toe, camber, and caster. Toe is the angle at which the car’s front tires point. Toe can be expressed in either degrees or fractions-of-an-inch. The toe setting is typically used to help compensate for rubber suspension bushing compliance while the car is moving.
A rear-wheel-drive vehicle pushes on the front tires as the car is driving down the road. The rolling resistance of the tires will cause a small amount of pressure being applied to the rubber bushings in the control arms. A small amount of toe-in allows the front tires to remain straight while the pressure is applied. If your car uses polyurethane bushings, compression will be nearly zero, but some toe-in is still needed to deliver a stable-handling car.
Adjusting a vehicle’s toe-angle can also alter its handling characteristics. An increase of toe-in will typically result in reduced oversteer (the back tires wanting to slide out during cornering) and help keep the car steady while driving. This will enhance high-speed stability. Increasing toe-out will typically reduce understeer (front tires sliding when going into a corner). Typical toe-in specs vary from 1/32- to 1/8-inch, depending on the vehicle.
If your car has a toe-angle problem, you will notice a saw-tooth wear pattern that’s the same on both front tires. The keyword is both front tires. A sawtooth pattern on only one tire is typically a suspension problem.
- Having too much toe – either in or out – can cause instability at high speeds and substantially increased tire wear. This is because the vehicle is fighting the excessive angle of the tires.
Camber is the amount of angle the top of the tire leans in. This is measured in degrees. If the top of the tire tilts in, the vehicle is experiencing negative camber. A tire that leans outward is experiencing positive camber.
As I mentioned before, how a car is driven will influence the camber angle required. An enthusiastic driver who enjoys cornering hard, will receive more cornering grip and longer tire life from a tire aligned with more negative camber. However, with the increased negative camber, a reserved driver’s lower cornering speeds would cause the inside edges of the tires to wear faster than the outside edges.
During negative-camber conditions, each tire develops camber thrust when the vehicle is driven straight ahead. Camber thrust describes the force generated perpendicular to the direction of travel of a rolling tire. Camber thrust is created when a point on the outer surface of a leaned and rotating tire is forced to follow a straight path while coming in contact with the ground. This is caused by friction. This deviation towards the direction of the lean causes a deformation in the tire tread and carcass that is transmitted to the vehicle as a force in the direction of the lean.
This is best described by the following: If your car encounters a bump that only causes one tire to lose grip, the other tire’s negative camber will push the vehicle in the direction of the tire that lost grip.
Settling on an appropriate camber setting that takes into account the driver’s aggressiveness will help balance treadwear with cornering performance. Since most of us use our cars for street driving, treadwear and handling requirements must reach a compromise. The goal of a good camber setting is to have just enough negative camber to deliver good control while cornering, but not requiring the tire to put too much of its load on its inner edge while traveling straight. Having less negative camber will reduce high-speed cornering capability but result in more even treadwear.
Two ways to notice your car has camber-alignment issues are: the vehicle pulls to one side (low tire pressure can also cause this) and uneven treadwear across the tread. Camber is easy to check with the alignment kit from Summit.
To adjust camber on most cars, you will add or remove shims which are located between the upper control arms and frame, or adjust an eccentric bolt.
- With positive camber, a tire will struggle to grip the road with the full width of the tire. It will also fight the lateral force of the road pulling sideways against the bottom of the tire.
- A wheel aligned in a straight-up parallel might appear ideal, however, the lateral forces will still pull it toward positive camber and utilize only a small portion of the tire’s available surface.
- A proper camber is a non-excessive amount of negative camber. This will allow utilization of the full tread width and aid in exerting downward force and tire grip.
Caster is the angle of the steering pivot. This angle is measured in degrees by comparing an imaginary line (vertical plane) running through the upper and lower ball joints. Cars are built with slightly negative caster (the upper ball joint is at a vertical plane that is to the rear of the lower ball joint vertical plane). If the top of that imaginary line angles toward the rear of the vehicle at the top, this is positive caster. If the line at the top leans forward, this is negative caster.
An increase of positive caster will increase steering effort and straight-line tracking. It will also improve high-speed stability and cornering. Positive caster also increases tire lean when cornering (like having more negative camber) as the steering angle is increased. If your car feels like it is too easy to steer and even wants to “wander” while going down the road, this could be too much negative caster.
- Caster is the axis at which the wheel pivots or turns. If this axis is straight up and down, the car would have neutral caster.
- Positive caster will increase negative-camber gain when turning. This will increase tire grip. It also improves stability while driving straight, but at the cost of increased steering effort.
- A small amount of negative caster reduces the effort required to turn the steering wheel. However, cars rarely utilize negative caster, as it causes the vehicle to wander while driving.
Taking a few minutes to check your alignment from time-to-time will make your tires last longer and your vehicle handle better. Even if you choose to have a shop align the vehicle after you use this kit, you’ll have a better understanding of the process – and knowledge normally equals power.
Hopefully, this short tutorial in vehicle alignment will give you the confidence to understand how you can re-align your classic’s front end after a repair or upgrade. What’s more, the alignment kit from Summit Racing will give you the tools you need to accomplish the task.