Early automobile fenders were set over the wheels to prevent mud, sand, and dust from being thrown onto the body and the occupants. Fenders typically became a more integral part of overall auto bodies by the mid-1930s. In contrast to the slab-sided cars, the
Volkswagen Beetle had real bolt-on fenders over both its front and rear wheels. In current US auto industry nomenclature, only the panels over the front wheels are usually called fenders. The auto industry changed from rear fenders bolted onto a quarter panel to an enlarged welded-on quarter panel that fulfilled both functions. This resulted in one piece where there had previously been two, and the name of the larger welded piece, the quarter panel, survived the consolidation. Quarter panels are at the rear, with an exception made for dual rear-wheel trucks, where the panel at the rear is called a fender. For vehicles with a narrow car body that exposes the tire, the fender is an exposed curve over the top of the tire. For wide-body vehicles that cover the tire, the fender forms the
wheel well surrounding the tire and is not directly visible from above the car body. The fender's openings for the wheel wells tend to be much larger than the tire's diameter because they accommodate suspension travel and must be large enough to allow the full range of tire motion on the suspension without touching the interior of the wheel well. The streamlined 1949
Nash 600 and
Ambassador design were the first to feature fenders that enclosed the front wheels. More elaborate designs include
fender skirts for enclosing the outside edge of the wheel well, and stylized
pontoon fenders for exposed fenders. The bolted panel that covers the wheel on dual-rear-wheel pickup trucks is called a fender. A pickup truck with a separate bed but without bolt-on fenders has a bedside, which performs the function of a fender. When the side of the bed is welded to the cab, as with the Cadillac Escalade and Chevrolet Avalanche, it is called a quarter panel. While the standard of bolted versus welded applies typically, some exceptions exist. Although attached by welding, the panels over the front wheels on cars such as the early 1960s Lincoln Continental, the Corvair, and the early-1960s Chrysler Imperial are called fenders. Similarly, even though bolted on, the panels covering the rear wheels on the Saturn S series are called quarter panels. An aftermarket pickup truck accessory is fender flares, which block mud and stones or cover rust. Manufacturers sometimes use them on models with wider tires than basic models. Using this method, the manufacturer can provide the needed tire coverage without producing a different fender, bedside, or quarter panel for what may be a low-production model. Fender flares are used on SUVs, pickup trucks, off-road vehicles, and sports cars. They either come with a vehicle as standard equipment or are added later as an aftermarket accessory. Fender flares are often made of fiberglass or ABS plastic to provide flexibility and lighter weight; however, some trucks and SUVs have metal fender flares to ensure better durability. There are three common styles of fender flares: OE style (narrow flares with smooth surfaces), bolt-on (wider fender flares with exposed bolts), and Cut-Out (oversized flares that require a fender trim). The most important characteristic of a fender flare is the width, as it shows the tire coverage. Common fender flares are wide.
Cycle wing Certain types of cars with narrow bodies, such as the
Lotus and later
Caterham Seven or the
Allard J2, use what are called
cycle fenders in the US or
cycle wings in Britain, for their resemblance to those used on bicycles. They are attached to the wheel suspension and remain at a fixed distance from the tire regardless of wheel motion. They can, therefore, be much closer to the tire than fixed wheel wells. This was popular on early
Classic Trials cars because the fenders were lightweight and allowed for a thin, streamlined body. They persist on cars wanting a "vintage" look. ==Bicycles and motorcycles==