Text by Cameron Parsons // Photos by Cameron Parsons // Illustrations by Paul Laguette
DSPORT Issue #166
The Big Three
Alignment comes down to setting up how your tires adhere to the road surface. Some might assume that positioning the wheels straight up and down and pointing them in the right direction does the job well enough, but this is rarely the case. An effective alignment takes into consideration the contact patch of rubber to the road and how the forces of the vehicle travel through the suspension and tires. There are three primary components that influence these areas: toe, camber and caster.Making the Turn
Toe-out assists in turn-in response, while Ackerman steering produces additional toe-out when negotiating turns. Nearly every car on the road today features the Ackerman steering principle. As the vehicle travels around a corner (1), the inside wheel (2) angles in more aggressively than the outside wheel (3). This difference in steering angle (4) allows the wheels to influence the steering more naturally, as the inside wheel must travel around a tighter turning radius than the outside wheel.
Although most racecars and streetcars both utilize varied amounts of Ackerman steering, racecars generally employ toe-out while streetcars are opposite with toe-in.
Toe to Toe
The simplest and possibly most commonly adjusted setting is the vehicle’s toe. The basic question to ask here is “are the wheels pointed straight?” If the front of the wheels point away from each other, this is negative toe, also known as toe-out. Positive toe, or toe-in, occurs when the front of the wheels point toward each other. Adjusting the amount of toe affects the vehicle’s responsiveness for turning as well as its straight-line stability at speed.
Tools for Good Measure:
A pair of toe plates (Intercomp part no. 102009) simplify the process of measuring toe. With the car level and steering wheel locked center, each plate secures flat against the two opposing tires. Hook a tape measure on the slot of one toe plate and measure the distance to the opposite side. Once you measure the distances between the front edges and rear edges on the plates, compare the two to reveal where the toe setting currently sits. Most drivers prefer only 1/16- to 1/8-inch of toe-out on the front end to improve turn-in, depending on the vehicle and its drivetrain configuration. Remember, even a small change like 1/4-inch of toe out versus 1/16-inch of toe out can influence the handling and tire wear of a vehicle, so make small adjustments at a time.
Effects of Camber Settings
(1) A wheel with positive camber struggles to grip the road with the full width of the tire, and fights the lateral force of the road pulling sideways against the bottom of the tire. (2) A wheel aligned straight up and down may appear ideal, however, lateral forces will still pull it toward positive camber and utilize only a small portion of the tire’s available surface (3). (4) A proper, non-excessive amount of negative camber utilizes the full tire width and aids in exerting downward force to maximize grip.
Full Tilt
Camber, the alignment component that visually stands out the most, refers to the vertical angle of the wheels. Here, you ask “are the wheels straight up and down?” If the top of the wheels lean in toward the top of the car, they are set up with negative camber. If the top of the wheels lean outward, they are set up with positive camber. Camber affects the tires’ contact patch and therefore the level of grip on straightaways and through turns.
Tools for Good Measure:
For dialing in camber, a digital gauge for precise measurements is a must. A purpose-built digital caster and camber gauge (Intercomp part no. 100005) and rim clamp (Intercomp part no. 100007) together provide the means to set the camber angle exactly to your liking. Using the clamp and gauge to mate perfectly flat with the wheel will display the amount of camber, negative or positive, to one-tenth of a degree. Increments of one-half of a degree at a time will usually provide a noticeable difference in drivability, tire wear and lap times. On rarer occasion, highly aggressive setups for streetcars and racecars at the track can reach up to three-degrees of negative camber and still prove beneficial. If you take it much further than that, you better be driving a Formula One car.
Caster Settings
(1) Caster is based on the axis at which the wheel pivots or turns. If this axis were straight up and down, the car would have neutral caster.
(2) Positive caster increases negative camber gain while turning, thus increasing grip. It also improves straight-line stability, but at the cost of increased steering effort.
(3) Dialing the setup toward negative caster reduces effort required to turn the wheel. However, cars do not utilize negative caster as it causes the vehicle to wander.
Forward and Back
Caster, often the most difficult component to visualize, refers to the angle of the steering pivot point. Viewing the car from the side, draw a straight line connecting the upper and lower ball joints or lower ball joint and strut tower mount to determine this steering pivot angle. The caster is considered positive if the line is angled forward, and negative if angled backward. The caster angle influences the vehicle’s stability at high speeds, the front wheels’ camber in relation to steering angle, and effort required to turn the wheel.
Measuring caster is done in a very similar way to measuring camber, with the help of a caster and camber gauge (Intercomp part no. 100005) and rim clamp (Intercomp part no. 100007). A set of turn plates (Intercomp part no. 102007) simplify the process even further. With the front wheels on the turn plates, turn them to either the 15- or 20-degree mark (turn right if measuring the right wheel, left if measuring the left ). With the clamp and gauge mounted to the wheel and set to caster mode, level the gauge and then zero it. Turn the wheel to center, and then to the opposite 15- or 20-degree mark. Once stopped at this angle, level the gauge again and it will provide the caster angle.
Tools for Good Measure:
Everything in Moderation
Nearly every vehicle component that you can adjust or tune has a sweet spot. Going full so on the chassis and suspension may lead to excessive body roll and a high-grip but sloppy handling. However, a fully stiff setup can make for dangerously snappy oversteer and put you into a wall. Somewhere in between lies a healthy compromise that matches the car’s driving potential to your driving style and ability. When working with alignment settings, you’ll find that small changes make a big difference in your car’s behavior, and that every car responds to these changes differently. Factory settings often serve as the best baseline to start with, before proceeding to make minimal changes based on what sort of performance you crave out of your vehicle. Next time you find yourself at the racetrack, take notes on how the car drives a er each session. Focus on one element at a time, such as turn-in, stability or grip levels, and make only one change at a time in an effort to improve performance. It won’t be long until you find yourself driving circles around those “hellaflush” show cars.