Used Tractor Trailers & Semi Trucks For Sale

Full Power, Semi Truck

What are semi trucks and why is it called a semi truck?

Semi trucks, also known as semi-trailer trucks, are a type of heavy duty and long distance transportation truck. Semi-trailer trucks are a combination of the tractor unit plus a hitched trailer in the rear for freight transportation. The chassis on its own is referred to as a "semi" or "semi truck" as it's incomplete or "half" without the attachment in the rear, typically a cargo van trailer or flat bed trailer.

Like other cargo trucks and freight trucks, semi trucks are powered by diesel engines for similar reasons: fuel efficiency, cheaper maintenance, and an overall cost-effective fuel source.

What is the difference between a tractor trailer and semi truck?

As mentioned earlier, the term semi truck refers to the tractor unit without a hitched cargo unit. A tractor trailer is a synonymous term with semi-trailer truck. These are just a few of the most common terms for a semi truck. Some other popular terms are 18 wheelers (this includes the wheels found in the trailers), big rigs, and truck tractors.

What are the different types of semi trucks for sale at Ritchie Bros. auctions?

Like dump trucks, semi trucks come in a variety of axle configurations which determine their intended usage from hauling capacity, length of your haul and type of cargo hauled.

Single Axle Semi Trucks

Single axle semi trucks, also known as 4x2 day cabs, have one single axle in the rear which receives power. Given the smaller chassis size and axle configuration, these single axle semis are perfect for short haul work.

Tandem Axle Semi Trucks

Tandem axle semi trucks are the most common semi truck as they are the most versatile. Given the dual axles in the rear, the applications extend compared to single axles. These can be found with day cab and sleeper cab configurations.

Tri Axle Semi Trucks

Tri Axle Semi trucks, also known as tridem trucks, are like tandem however they have an extra axle in the rear. Depending on the model of the unit and required application, the third axle is not powered, but only there to increase haulage capacity. Some models power all three axles which allows for better traction.

Terminal Tractor

The terminal tractor isn't quite a semi truck, but still falls under the category of a truck tractor. Its main purpose is to haul cargo, but not on urban roads. These are uniquely designed pickup-like trucks that operate in designated areas, such as warehouses, shipping ports, or airports.

Features and styles of semi trucks

Aside from axle configurations, the second most defining characteristic to look for when buying new or used big rig trucks are their cab types.

Sleeper Cab

For longer hauls that are out of state or cross country, a sleeper cab is the ideal choice as the driver now has the option of sleeping in the truck during night hours as opposed to finding and paying for accommodation mid route.

Sleeper truck cabs have an extension in the rear of the unit which contains a sleeping birth. Depending on the model of the truck tractor, some sleeping berths contain a single bed or a bunk bed. Some luxury & high-end models contain modern features that can be found in RVs.

Another advantage of sleeper cab truck tractors is that they can minimize any disruption in delivery time, if two drivers are in rotation of sleeping vs driving.

Day Cab

A day cab truck tractor is the simplest form of a semi truck cab type. Unlike sleeper cabs, day cab truck tractors are smaller (as they do not have a sleeping berth in the rear), thus much lighter than a sleeper cab.

For shorter trips and inner city hauling and transport, a day cab is more ideal. As mentioned earlier, it's a lot smaller in size and weight so it offers much more efficiency for smaller trips. Secondly, given its small chassis size, its maneuverability is far greater especially when in traffic. As sleeper cabs are more preferential for longer hauls, some used day cab trucks will also have lower mileage as it's the cab of choice for shorter hails.

Semi truck tips, industry news and more!

• Best semi truck to buy in 2025
• Everything you need to know about CDLs
• Kenworth vs Peterbilt. A full truck comparison
• DOT axle weight limits

Different ways to buy Semi Trucks & Truck Tractors at Ritchie Bros.

Ritchie Bros offers multiple ways to buy equipment such as auctions, Marketplace-E with instant offers and our new private buying experience at Ritchie List. Expand your search for Semi Trucks & Truck Tractors for sale today with our storefronts:

• Semi Trucks & Truck Tractors for sale on IronPlanet and Marketplace-E
• Semi Trucks & Truck Tractors for sale on Ritchie List
• Semi Trucks & Truck Tractors for sale on Boom & Bucket