All-terrain vehicle (ATV) nerf bars are small, steel, tubular devices designed to prevent a rider's foot from becoming trapped and injured by another ATV. Mounting to the frame of the vehicle, ATV nerf bars typically fit between the front and rear tires and protrude nearly to the outer edges of the tires. Some designs of ATV nerf bars include a webbing or panel that is placed horizontally across the top of the bars. This is intended to prevent a rider's foot from slipping off of a foot peg and being pulled under the rear tire during a rough landing or difficult area of track or trail.
The ATV nerf bars are intended to act like small, side-mounted bumpers for the vehicle. During a race, contact will often be made between two ATVs, with the typical result being the enmeshment of the tires of the two vehicles. This is dangerous in any form of open-wheel vehicle racing as the tires tend to attempt to climb up and over each other, resulting in spectacular airborne flips, wrecks and crashes. By placing a small tubular bumper between the two tires, the contact is often limited to a simple bump and continued racing for each rider.
In most racing applications, the ATV nerf bars are replaceable by simply unbolting the bars and placing new bars into position; however, in factory stock applications, the bars are often welded to the frame. The advantage of a replaceable component on a racing vehicle is the ability to make repairs in a hurry and without cutting the old part off and welding the new part in place on the vehicle. Some riders also prefer to use different types and sizes of ATV nerf bars for different conditions or on different tracks.
Racing ATV nerf bars are made of a lightweight aluminum to reduce the weight of the vehicle. This has both positive and negative connotations. While the bars are lightweight and allow the vehicle to accelerate slightly faster, the lightweight alloy also offers less protection for both the vehicle and the rider.
This sacrifice of strength for weight can often be the demise of a race team. The lightweight ATV nerf bars can be bent due to moderate contact, thereby blocking a rider's access to a shifter or brake lever. In this scenario, the desire to save a miniscule amount of weight in the form of lightweight ATV nerf bars can result in the ATV being unable to finish a race, with the ultimate result being a loss of income.