What is this? Front-wheel drive vehicles use negative toe-out to avoid forward movement and enable tires to move side by side at a relatively good speed. Excess toe-out can cause the inside edges of tires to wear out quickly, braking issues, and understeer issues.
TOE IN & OUT
'Toe' is the term given to the left-right alignment of the front wheels relative to each other. Toe-in is where the front edge of the wheels are closer together than the rear, and toe-out is the opposite.
Poor camber and caster alignment can cause your vehicle to "pull", and can cause tire tread to wear unevenly. Toe in won't cause your vehicle to pull, but it can cause extremely fast tire tread wear.
Toe is actually measured as three angles-the angle that the left and right tires sit in relation to a line drawn down the center of the car from front to rear (Individual toe-L&R), and their combined angles (total toe) off the centerline.
Performance Benefits of Positive Caster
You get better handling when cornering, better stability at high speeds, and better straight-line tracking. The better traction while cornering is similar to a vehicle with negative camber, as it keeps more tread on the ground despite the sharp angles.
Typical toe-in specs vary from one-thirty-second to one-eighth-inch, depending on the vehicle. Check a service manual for your car's acceptable range. The best tip-off to a toe problem is a saw-tooth wear pattern that's equal on both front tires.
Your acceptable range is -0.4 – +1.3 degrees. The specifications for toe are read in fractions of an inch or degrees. The QuickTrick systems utilize inches or metric. (Tape measures come in both) In this case, we would shoot for as close to 0 toe in or out as possible.
Turns out each mm of difference corresponds to ~0.1 degrees with 21" wheels, and ~0.11 degrees with 19". You can do the trig, or just use my numbers. So on the right rear wheel I have 0.10 degrees toe-in. On the left I have 2 mm, or 0.20 degrees.
|Total rear toe-in (degrees)||0.25||0.45|
Generally the rule of thumb is that more toe-in increases understeer and more toe-out increases oversteer. However, with modern cars, especially race cars with independent front and rear suspensions, there is another effect on handling.
To answer your question, adjusting toe does NOT change the camber. Changing the camber DOES change toe.
Excess toe-in will increase wear to the outside of the tire. When the front of the tires are further apart than the rear, the wheels are toed out. Excess toe-out wears the inside of the tires. Proper toe is a static reading given by the vehicle manufacturer.
There are three main causes of wheel misalignment, these are: Sudden jarring or heavy impact caused by hitting something, such as a pothole, bumping a curb, or a road accident. Worn parts caused by wear and tear.
Negative toe, or toe out, is the front of the wheel pointing away from the centreline of the vehicle. Positive toe, or toe in, is the front of the wheel pointing towards the centreline of the vehicle.
You shouldn't run too much rear toe-in on a drift car. By doing so, you'll have a car that will straighten up if the throttle is lifted or modulated. This is the leading cause of serious drift car crashes. A car's understeer/oversteer balance should always be adjusted in the suspension, not by using the toe.
Caster is the angle that identifies the forward or backward slope of a line that is drawn through the upper and lower steering pivot points. It does not affect tire wear, but caster does have an influence on the directional control of the steering.
Toe-out on turns is measured by the turning angle gauges (turn plates) that are a part of every wheel alignment machine. The readings are either directly on the turn plate or they are measured electronically and displayed on the screen.
Dated : 09-Jun-2022
Category : Education