Rearward tilting of the strut when viewing the front wheel from the side.
(As shown in the figure, when caster is tilted rearward, the front wheels are pulled backward by the tires contact to the road. This reduces sideways vibration in the front wheels and also makes it easier for the wheels to recover their forward position after being turned. This "caster effect", helps keep the vehicle stable in the straight ahead position and improves steering correction.)
