Rohit Damodar, one of Bukkehave’s resident truck experts, sets us straight on semi-trailer trucks in different regions. 

Did You Know …

A semi-trailer truck, also known as tractor-trailer is an articulated truck consisting of a towing engine (tractor in the United States, prime mover in Australia, and truck in the UK, Canada and New Zealand), and a semi-trailer that carries the freight.

Other common terms for semi-trailer truck include truck and trailer, transfer truck, 18-wheeler, Mack truck, big rig (US), transport (Canada), artic (UK and Ireland), and juggernaut (UK).

Regional Configurations of a Semi-Trailer truck

North America

• In North America, semi tractors usually have 3 axles, the front steer axle having two wheels and the two rear drive axles having a pair of wheels (dualies) on each side.
• In some cases dual wheels are replaced by tires known as "super singles" to reduce the weight of the tractor. "Super singles" are substantially wider than normal tires.
• The cargo trailer usually has two "tandem" axles at the rear, each of which has dual wheels, or 8 wheels on the trailer.
• Trailers are optionally equipped with moveable tandems that can be set to balance the weight of the trailer to stay within legal limits.

Continental Europe 

• The noticeable difference between tractor units in the U.S. and Continental Europe is that most European models are forward control or cab over engine, while most U.S. trucks are conventional or normal control meaning the engine is in front of the cabin.
• A forward control truck allows greater maneuverability, as the driver need only gauge distances behind his seating point, and this allows for shorter trucks with longer trailers within the legal maximum total length.
• In continental Europe, most semi tractors have two axles, again with the front steer having two wheels, and rear drive, having twin wheels on each side.
• The cargo trailer usually has three axles at the rear, with single wheels, or six wheels in total.

Forward control, or cab over engine	Conventional, or normal control

United Kingdom 

• In the UK both tractor and semi-trailer have 3 or more axles each.
   
• Here some articulated trucks have 8 tires on 3 axles on the tractor. These are known as 6 wheelers, with either the center or rear axle having single wheels which normally steer as well as the front axle and can be raised when not needed.
• Some trailers have 2 axles which have twin wheels on each axle. Other trailers have 3 axles of which 1 axle can be a TAG axle, which has super-single wheels.
• The UK also allows artic truck tractors, which have 6 tires on 2 axles; these are known as 4 wheelers.

Australia

• Australia has a reputation for using very large trucks and road trains for transportation by road. The popular configurations of trucks in general have dual drive axles and three axles on the trailers, with 4 tires on each axle.
• In Australia, cabovers are most often seen in areas where the reduction in total length allows the vehicle to pull longer trailers and thus more cargo than it would otherwise.
• The suspension is designed with travel limiting, which will hold the rim off the road for one blown or deflated tire for each side of the trailer, so a trailer can be driven at reduced speed to a safe place for repair.
• Super singles are also often used on the steer axle in Australia to allow greater loading over the steer axle.

References: www.wikipedia.org