It’s time for you to show off to of all of your friends how savvy your are with suspension tech. Debunk the myths of lowered vehicles, figure out how to make your road car turn better, and stump the employee and you local car shop. Are you ready to dive and learn what it takes to make your car handle like a champ? The answer is yes!
So this is our attempt, to make camber and caster sexy! To show you, there’s a lot going on there. Starting with the first component: Camber.
Camber is probably the most talked about component for suspension tuning, and most easy to spot. When looking at the front (or rear) of your tire, Camber is a measurement of the centerline of your tire in relation to the flat ground surface. (Note: For the Independent Rear Suspension drivers (IRS), camber can be adjusted on the front and back of the vehicle. For rear solid axle folks, this applies to just the front.) Overall, camber is broken down into three aspects of Negative, Neutral and Positive.
Image Source: http://www.comeanddriveit.com
This is what owners love so much. When looking at the front of the tire, it’s when the top tucks inwards. For a normal road car you typically want to maintain a slight amount of negative camber (Usually .5 – 1 Degrees) to improve road handling. For racing, this can be tucked in a few more degrees because negative camber improves handling by allowing the tire to apply even loading when g-force of the car body rolls into a corner. Just imagine a parallelogram that straightens to a square. That’s basically what your tire does during a corner with negative camber.
Now you can understand why negative camber is widely used for road racing. Because running only a small amount for extreme racing conditions will cause the tire to load the outer portion of the tread during corners — which reduces the overall grip and traction. The downside to running a lot of negative camber is causing the inner portion of the tread to wear faster during normal street driving.
Static or Neutral Camber
This is when the tire centerline is 0-degrees (A symmetrical 90-degree angle) to the ground surface. This isn’t optimal for road racing, but for straight-line drag racing, or an everyday streetcar, neutral camber reduces the amount of resistance or drag that negative (Or positive) camber can cause. Which ultimately reduces tire wear.
Most streetcars will be set to around .5 – 1 degrees of negative camber to allow a bit of traction control and transition to full neutral camber (0 Degrees) through corners. Although many drag racers run enough negative camber, so that when the front end lifts from torque, the camber sets to neutral to create less tire drag.
This is when the top of the tire extends outward, and the base of the tire tucks inwards. This is rarely ever seen on a road car since this will extremely reduce road-handling capabilities. Only in specific racing situations, such as NASCAR, is positive camber used. In this case it is applied to handle the degree of track embankment. If you are running a positive camber figure on your streetcar immediate have your suspension checked for damage and adjust the camber to a negative figure. Just goes to show you, NASCAR drivers are crazy.
Caster is a little bit more tricky. When looking at the side of the tire, you have to image a vertical centerline on the wheel. This is called the vertical steering axis; the wheels pivot’s on this axis. Now imagine the shock (or strut) on that same vertical line. When you adjust the angle of the shock in relation to the steering axis, you are adjusting caster.
Image Source: http://www.comeanddriveit.com
is when the steering axis is “in front of” the vertical shock axis. So the top of the shock would be pushed towards the rear of the car. Positive caster creates a lot of align torque on your steering, (This is a force that straightens the steering wheel when you roll forward) which improves straight line stability of the car. As you increase positive caster the steering will become heavier. Although with modern power steering systems this is rarely a problem. Generally you want as much positive caster as you can reasonably get so long as the car is equipped with power steering
is when the steering axis is “behind” the vertical shock axis. Most modern vehicles do not use negative caster. For it lightens up the steering, but usually causes the vehicle to wander on a road. It will lighten the steering effort but also increases the tendency for the car to wander down the road.
Lastly is the toe alignment. But if you have a decent amount of experience driving a car, you should easily know what toe alignment is. But, in those situations whenthe mechanic can’t seem to get the alignment quite right, now you can diagnose the camber and caster. Or just blow him away when you explain the inner tires are wearing because the camber is set with too much negative.