A tandem axle refers to a configuration of two axles placed close together on a vehicle, typically used in trailers and heavy-duty trucks. This design helps distribute the weight of the load more evenly, improving stability and reducing wear on tires. It allows for better handling and increased load capacity compared to single axle setups. Tandem axles are commonly found in semi-trailers, dump trucks, and recreational vehicles. By having two axles, these vehicles can carry heavier loads while maintaining better traction and control on the road. This makes tandem axles a popular choice for transporting goods and materials efficiently.