Off-Road Terms Glossary

Stands for anti-lock braking system. They are designed to prevent skidding when you hit the brakes hard, but not locking up, but rather a rapid lock release action allows some steering whilst braking.

The turning angle of an inside wheel is different than the turning angle of the outside wheel, because the inside wheel travels a shorter path. This difference, which is an engineered value, is called the Ackerman angle, also known as toe-out turns.

This term refers to an affordable technique for lifting a vehicle, which involves inserting an extra leaf to the leaf spring pack. Add-a-leaf achieves the lift, but degrades ride quality.

Aftermarket describes automotive parts that are not produced by an original equipment manufacturer (OEM).

The measure of force exerted by the air inside a tire, typically measured in pounds per square inch (PSI), or kilopascals (kPa).

Amp draw is the amount of ampere-hours consumed by a piece of electrical equipment during operation. An ampere-hour is a measure of the energy a battery can hold and supply at a specific voltage.

Approach angle refers to the steepest angle a vehicle can climb before the body, front-mounted equipment, or chassis makes contact with the ground.

Aspect ratio is a tire's height divided by its width, expressed as a percentage. The ratio characterizes the profile of the tire.

An Axle Shaft is the part of an axle assembly that is turned by the side gear of the differential and transfers the power either directly to the wheel or to the wheel hub that the wheel is bolted to, depending on the style of axle.

Axle wrap describes when an axle turns in the opposite direction of the circular torque generated through acceleration. Tension builds in the spring, but it will eventually snap back harshly. This happens more often when towing, and can be destructive to drive shafts and u-joints.