Information about semi trailer truck
A semi-trailer truck, also known as tractor-trailer or articulated lorry, is an articulated truck or lorry consisting of a towing engine and a semi-trailer (plus possible additional trailers) that carries the freight.
Colloquial terms for semi-trailer truck include truck and trailer, transfer truck, 18-wheeler, semi, Diesel, Mack truck (named for a prominent brand), big rig (US), transport (Canada), artic (UK and Ireland), and juggernaut (UK).
In North America, semi tractors usually have 3 axles, the front, or “steer”, axle having two wheels, and each of the two rear, “drive”, axles having a pair of “dualies” (double) wheels on each side. Thus, the most common configuration of tractor has 10 wheels, however in some cases dual wheels are replaced by tires known as “super singles” to reduce the weight of the tractor. In this case the tractor will only have six wheels. “Super singles” are substantially wider than normal tires. A smaller tractor having a single drive axle (six wheeler) is often used to pull shorter trailers in tight urban environments, such as downtown areas where a 60-foot rig would be too difficult to maneuver.
