Reserverädern

Reserveräder, often called “spare wheels” in English, are additional or backup wheels intended to replace a damaged or lost tire on a vehicle. Their primary purpose is to allow drivers to continue traveling after a puncture or severe tire failure, ensuring safety and minimizing downtime. Vehicles equipped with a reserve wheel carry a simple mechanism—usually a rear door or trunk compartment—where the spare is stored. Depending on vehicle design, the spare may be a full-size wheel or a space-saver, also known as a “donut” spare.

Full-size reserves match the original tires in diameter, tread pattern, and pressure rating, enabling normal driving conditions until permanent repair. Because they avoid the speed and handling restrictions of space-saver discs—limited by vehicle and tire design—full-size spares are common on passenger cars, trucks, and many passenger aircraft. Space-savers, however, are lightweight, have a smaller diameter, and are intended only for short distances at reduced speeds. They must be used carefully, as their reduced size can affect vehicle balance and braking performance.

Regulatory bodies, such as the German Kraftfahrt-Bundesamt and the European Union, have guidelines regarding spare wheel placement, labeling, and use. Some modern safety programs even recommend “run-flat” tires, which can eliminate the need for a spare by prolonging safe driving after a puncture. In such designs, a small spare may still be carried but is often a full-size disc to counter the lack of tire tread for longer distances.

Historically, the concept of a reserve wheel dates back to early automobile development when tire quality varied widely. The term “Reserve” originates from the French and German usage of the word for “reserve” or “extra.” In contemporary use, the spare is a standard safety feature in most commercial and passenger vehicles worldwide, with variations reflecting vehicle type, usage, and local regulations.