Why are big trucks called semis?

Why are Big Trucks Called Semis?

Trucks are a sight that you see every day on the roads of the USA. The dedicated truckers take food and other goods that we need on long journeys from source to destination, keeping stores stocked even in the worst of the weather. The US road network was practically designed around the needs of trucks, and as a business worth hundreds of billions of dollars this is one that is very much a bedrock of the US economy.

For most people, the most exciting trucks are the biggest, those we know as ‘Semis’. How did they get the name and why has it stuck? Let’s start by looking at what a Semi truck is, and what makes it so.

What Makes a Semi?

Semis are the biggest trucks on the roads, and the ones that carry the heaviest loads. They cover vast amounts of miles in a given year and need maintenance throughout. This is why many owners and fleet managers rely upon Find It Parts for quality truck parts, to keep them going constantly. So, what classes as a Semi?

The name comes not from the truck itself, but from the trailer that it tows. These trailers – you’ll have seen them waiting for a cab to pick them up – have no front wheels. As such, they can only move – or become an actual trailer – when attached to the truck itself. As such, they’ve always been known as ‘semi-trailers’: not a full trailer! The name transferred to the trucks themselves and has stuck. Most people now refer to a truck of this type as a semi-truck.

In the USA, a semi-truck – one of the classes of Heavy Truck which we will talk about below – can haul a load up to 80,000lbs. If you think that’s a lot, in Australia – where there is much less traffic on the roads – they have semis known as Road Trains that tow up to four trailers and a maximum of 300,000lbs.

A semi-truck is sometimes referred to as an ’18-Wheeler’. This is a reference to the fact they tend to spread the weight typically between 18 wheels. So, that’s basically what makes a truck a semi – the semi-trailer, and the 18 wheels. Now let’s talk about the different classes of truck, and the brands you may have heard of.

Different Classes of Truck 

There are 8 different classifications covering trucks in the USA, spread between Light, Medium and Heavy trucks. The Light truck classes – 1, 2a and 2b – include such favourites as the Ford F150, but it’s classes 7 and 8 – Heavy Trucks – that we’re interested in. These enormous trucks cover massive mileages during their lives and are driven constantly, and are built by some of the most iconic names in the US vehicle industry.

Consider this: 190,000 heavy trucks are sold in the USA each year. That’s a massive number of vehicles on the roads in just one class. Who are they made by? The market leader for heavy trucks and semis is Freightliner. They have a market share of more than one-third of the total sales. Other names in the semi market include Peterbilt and Mack – both famous names in trucking folklore – and of the 1.9million trucks, most are based in California, Texas and Florida. Between them, the combined mileage of US trucks in a given year amounts to more that 140billion miles, with 70% of all freight in the USA being transported by semi-trucks. Those figures make interesting and quite amazing reading, we’re sure you’ll agree! It’s no wonder, then, that trucking is a job that is one small boys – and more increasingly girls – aspire to!

Trucking for the USA

It’s entirely possible that the truck was invented in the USA, so it’s appropriate that trucking has become such a part of US lore. Indeed, the likelihood is that the origins of the truck as we know it – a vehicle for carrying goods rather than passengers – has its roots in the 1920’s when commercial users attached home-built pick-up bodies to the venerable Ford Model T. Not only was great American hero responsible for revolutionising the motor car industry, but he’s also part of trucking legend too!

Trucking is not an easy job, but those who do it for a long time often find it satisfying. Long journeys alone – or, in some cases, with a co-driver – may not be for everyone, and as the weather can change dramatically from one part of the continent to another it’s essential a driver knows what they’re doing. However, it’s a job that needs doing, and will always be around as long as we need freight moving across the country.

The semi-truck may just be the most important vehicle in the USA right now, so long may we appreciate the sight of these magnificent machines on our roads.