Bulldozers are heavy-duty machines that are ideal for pushing around large debris and clearing large areas. They consist of a tractor with a blade on the front. You can break them down into different types based on the type of blades they have, the way they maneuver, and other notable characteristics.
Straight blade bulldozers feature the most basic blade. The blade is fairly short and consists of a straight piece of metal with no curves, wings or other features. Straight blades work well for grading and evening out the soil, but not for heavy moving or pushing.
Bulldozers that feature a "U blade," also known as a universal blade, works well for pushing and hauling heavy loads of large debris. The blade is high and curved, making it ideal for scooping. Universal blades also have wings on either end of the blade, which helps keep the debris in the center of the blade.
Combination blade bulldozers combine the designs of the straight and universal blade. The blade will be taller than a regular straight blade and offer a slight curve, rather than being completely straight. Side wings are smaller than those on the U blade. Combination blades are ideal for medium loads that still involved hauling and pushing.
You can also classify bulldozers by their means of mobility—either tracks or tires.
Track bulldozers, also known as crawlers, use heavy rubber or steel treads to move. They are large, powerful, and slow, and are ideal for scaling hills and mounds because of their enhanced stability. Crawler bulldozers often feature a ripper at the back. The ripper is a strong set of claws that can crush rock and other debris for easier hauling.
Tire bulldozers are outfitted with large tires, rather than tracks. Bulldozers using tires are much faster and lighter than crawler bulldozers, but not as powerful or stable. They are great for finishing work, such as leveling a large construction site, or for moving lots of material on a fairly level surface. Rubber tires do not generally damage paved surfaces, whereas tracks can tear up paving.
Bulldozers can have other features that classify them into different categories. Hybrid bulldozers are now available, working from a combination of liquid fuel (gasoline or diesel) and electricity. Swamp bulldozers are outfitted with a special undercarriage that allows them to move through wet and muddy areas easily and without damage. And, of course, bulldozer blades are made to put on a variety of different vehicles, such as ATVs, utility tractors, and skid steers, for small or lightweight jobs that don't require a heavy-duty bulldozer machine.