Tires can lean to front or rear {caster, tire}, rather than be vertical. Positive caster is forward tilt. Too much positive caster causes shimmy, because weight falls in front of tread. Too little positive caster causes poor tracking, because weight falls down tire center.
Caster settings typically are 0.5 to 4 degrees. From 3 to 4 results in better straight-line tracking but heavier steering. From 0.5 to 1 makes lighter steering, but poorer straight-line tracking.
Negative caster is backward tilt. Negative caster puts weight behind tire and causes unstable tracking, because it pushes tire forward in various directions.
Practical Affairs>Machine>Kinds>Mechanical>Rotation>Tire
7-Machine-Kinds-Mechanical-Rotation-Tire
Outline of Knowledge Database Home Page
Description of Outline of Knowledge Database
Date Modified: 2022.0224