Ref.: MEL-WA(3D HCV) - OM Ver.1.7
13
NEGATIVE CAMBER
is the inward tilt of the tyre at the top.
Fig. 3
If a tyre was absolutely vertical, the degree of camber would be zero. Unlike the
Caster angle, Camber will change with vehicle load and ride height. With the weight of
the driver in the vehicle, front left Camber will increase and front right Camber will
decrease and vise versa for left hand steering vehicle. As rough road conditions are
encountered, the downward thrust of the vehicle body will cause front Camber to go
negative. As the vehicle body movement returns upward, front Camber will go positive.
A tyre with Positive Camber can influence the vehicle with a directional pull. The
vehicle will go towards the side that has the tyre with the most Positive Camber.
It is the normal tendency of the tyre to roll around the center of a circle when the top of
the tyre is inclined towards the center of that circle. Positive Camber tends to place
the tyre-to-road contact area nearer the point of load. This assists in easier steering
and forces the thicker inner portion of the spindle to carry most of the load. Modern
suspension design has reduced the need for considerable Positive Camber. Many
manufacturers specify a slight amount of Negative Camber. Some manufacturers
recommend an additional 1/4 to 1/2 degree Positive Camber on the right wheel to
compensate for road crown. The car will then pull toward the side with greater Positive
Camber. This will offset the pull effect of the road crown. Always set Camber within
specifications.
Rear Camber Angle - Front Wheel Drive
Rear wheel Camber angle is being relied on for improved steering and general
handling performance. In the past FWD vehicles and independent rear suspension
vehicles were most likely to have adjustable rear Camber. On vehicles currently being
produced, rear Camber adjustment capabilities are being found on all types of models
(Note : Always use full-floating tables under wheels whenever alignment is being done.
When alignment problems are reported on vehicles with fixed rear axles and no rear
wheel Camber adjustment capabilities, a thorough inspection of the rear suspension
should be made. Damaged or worn components can cause alignment and / or steering
problems. Replacing or repairing the defective components should bring the rear
wheel assemblies into specification.
On vehicles where rear wheel Camber is adjustable, all previous precautions apply. If
Camber adjustment requirements are excessive, a thorough inspection must be
performed. Replacing any defective components could bring the Camber into
specification and adjustment may become unnecessary. As with the front suspension,
DO NOT perform alignment on vehicles with damaged or worn components.
Rear Camber Angle - Rear Wheel Drive
On RWD vehicles, where rear Camber is usually not adjustable, Camber will normally
be fixed at zero. Even though this angle cannot be changed through adjustment, if rear
suspension abnormalities exist, a thorough inspection must be made. Not to be
overlooked are the rear springs. Worn or weak rear springs will alter riding height and
because of a reduction in tension, will bring the shock absorbers out of the optimum
range of their dampening ability. The result will be excessive tire movement. This
condition reduces operator control and contributes to abnormal tire wear. As in FWD
vehicles, replacing worn or defective components may bring rear wheels within
specification.
