Diesel forklifts are best suited for outdoor projects and jobsites. Diesel engines have exhaust emissions that could be potentially hazardous and negatively impact the health of your workers. Diesel exhaust emissions are gases and vapors such as nitrous oxide, nitrogen dioxide, sulfur dioxide and carbon monoxide, as well as fine particles known as diesel particulate matter (DPM).

The forklift weight greatly depends on the type, size and configuration. A 5,000-pound capacity forklift can weigh up to 7,000 pounds with load and fuel. United Rentals can help you select the right forklift for your site, facility and task needs.

Yes, a forklift operator must have a valid license to use a forklift on any worksite in the U.S. United Rentals offers Equipment Operator Training and certifications to those who require them. Make sure you read our Project Uptime article, Forklift Safety 101.

Warehouse forklifts

Warehouse forklifts are best for raising and transporting crates, pallets and other materials over short distances. As their name implies, they’re often used in warehouses for loading and unloading inventory as well as picking and stacking. They can handle heavy loads and operate on indoor surfaces or smooth outdoor surfaces.

Warehouse forklifts come in different types. If you need the ability to move loads to the side, look for a side loader or a warehouse forklift with an available side-shift attachment. A walkie stacker is a walk-behind forklift designed to move and stack pallets at greater heights than a standard pallet jack. For the highest reach, choose a quad mast forklift.

Telehandlers

For raising materials off the ground as high as 115 feet, you’ll need a telescopic handler, aka telehandler forklift or reach forklift. Unlike a traditional forklift, a telehandler has a telescopic boom for lifting materials and can be used to extend loads up and over obstacles. The boom can be fitted with various attachments, such as a crane hook attachment or material bucket. The larger telehandlers with maximum capacities of 10,000 lbs. and over have outriggers to stabilize the machine for heavier and higher lifts.

Straight mast rough terrain forklifts

If you’ll be moving materials over uneven surfaces or rough surfaces, you may need a rough terrain forklift, popular on outdoor construction and industrial sites. These machines are suitable for use on uneven, rough, soft, sandy or muddy surfaces. For extra traction on muddy jobsites, consider renting a 4-wheel drive rough terrain forklift.

Choose a forklift with sufficient maximum capacity and make sure it can fit where you need it to go.

Think through what materials you plan to lift (single pallets? heavy containers? wood?) and the heaviest loads you’ll need to lift. It’s common for people to underestimate the capacity of the forklift they need, so when in doubt, go for a larger forklift rental. In the case of forklifts with telescopic booms, consult the load chart to figure out the forklift’s load capacity.

In addition to capacity, you’ll also need to consider the forklift’s dimensions in relation to the space restrictions of the jobsite. For example, if you’re working in a warehouse, knowing the aisle width and/or common pallet dimensions will help to determine the size and type of forklift to rent. Pallet jacks and side loaders are ideal for narrow aisles.

The height to which you need to lift materials will determine not only what type of forklift you need to rent but also the type of mast you need (straight or extending, and how many stages). Forklift masts are typically two-stage or three-stage, though some are four-stage (quad masts). Quad masts are designed for the highest stacking.

Remember to consider your overhead clearance, including doorways, and make sure the mast (or boom in the case of a telehandler) at its lowest height will fit. Four-stage masts collapse to a lower height than other masts.

If you’ll be working indoors, an electric forklift, powered by rechargeable batteries, might be a good bet. They’re quiet and produce no emissions. They cost more than other models, but they also save you a considerable amount on fuel. Of course, you’ll have to take the time to recharge the battery. A liquid propane gas (LPG) forklift can operate indoors or outdoors. Diesel forklifts are typically reserved for outdoor use, though newer machines with Tier 4 engines can be used indoors because of their low emissions.

Most forklifts are designed for a specific type of tire, so chances are, if you’re using the right forklift for the terrain, it will have the right tires.

Pneumatic tires, filled with compressed air, can handle rough terrain and uneven surfaces, including those found on construction sites and in lumberyards. Forklifts with pneumatic tires are typically intended for outdoor work, though they can also be useful in large warehouses. Cushion tires, made from solid rubber, provide less traction and lower ground clearance and are intended for indoor floors and smooth, level outdoor surfaces.

Forklift load capacity is a crucial specification for choosing the right forklift. Capacity is determined by the manufacturer, indicating the maximum amount of weight the forklift will lift to a pre-determined fork height at a specified load center. The most common load center is 24 inches. 

Class I – Class I electric forklifts, or hand trucks, are optimal for general warehousing industries, including retail, food storage and factory, and are popular for indoor use.  

Class II – Class II forklifts allow for maneuverability in narrow, indoor spaces and are ideal for storing inventory. Types include order pickers, reach trucks and turret trucks.  

Class III – Commonly used to transfer pallets or carts to alternate forklifts, Class III forklifts include electric pallet jacks, stackers and tow tractors.  

Class IV – Also known as internal combustion engine (ICE) trucks, Class IV forklifts have puncture-proof solid/cushion tires that are designed for indoor use. These forklifts run on diesel or liquid petroleum gas.  

Class V – Similar to the Class IV ICE forklifts, Class V forklifts are more versatile, allowing for both indoor and outdoor use, fitted with pneumatic tires intended for rough surfaces and outdoor terrain.  

Class VI – Consisting of both electric and internal combustion tow tractors, Class VI forklifts tow product rather than lift it. They are commonly used at airports and in assembly lines.  

Class VII – Class VII forklifts are diesel fueled and designed for rough terrain. They are regularly used outdoors at lumber yards and construction sites. 

A forklift counterweight leverages extra weight in the chassis (typically a counterweight or counterbalance is on the opposite end of the forks) to counterbalance a load against the center line of the drive wheels. On some types of forklifts, like telehandlers or reach forklifts, outriggers act as the counterweight/counterbalance. Outriggers are extendable "feet" that extend and make contact with the ground, providing stability for heavy loads. 

The data plate or rating plate of a forklift is a sheet, mounted on the body of the lift, that lists vital forklift information, such as load capacity, fuel types, serial number and lift height. Most commonly, the data plate can be found on the instrument panel, near the hydraulic controls. It’s important for users of the forklift to be familiar with the data plate, as it lists important product limitations and maintenance requirements. The term data plate can often be used interchangeably with terms like capacity plate, weight plate and nameplate.   

The free lift height is the maximum height you can raise forks to before changing mast height. This specification is good to know when working in a building with low ceilings or a trailer. 

A forklift lift cylinder is the hydraulic mechanism that lifts and lowers the forks. It’s a single-acting mechanism, which means that it only moves in one direction.   

Maximum fork height (MFH) — also called maximum lift height or mast height — is the maximum height the forks will reach when the mast has reached its full extension.  

The load center of a forklift is between the base of the forks and the load’s center of gravity. It determines the amount and distribution of weight on the lift. The forklift’s center of gravity changes based on whether the lift is loaded, and the load center, when holding product, helps determine the pivot point of the lift. While the load center of a forklift varies, pallets most commonly have a 24-inch load center if the length of the pallet is 48 inches long.  

There are multiple factors to consider when choosing between the different types of forklifts. Among those factors are the different types of masts and which forklift mast type best suits your needs. The mast is the vertical component that allows the forklift to lift and lower its load. Masts can have different numbers of extending sections, from single-stage to quad. Single-stage masts have one channel and lack free-lift capabilities. Free lift describes when the forks of the lift can be raised or lowered without manipulating the mast channels.  Two-stage (or duplex) masts allow for double stacking and can free lift. Three-stage masts, the most common, allow for higher reach because of their three stages. These are also called triple-stage or triplex masts. Quad-mast forklifts have four sets of moving rails, which allow for a reach of 22 feet.  

Cushion tires are made of solid rubber fitted around a metal ring. They are lower maintenance, tend to be cheaper and allow for smaller turning radiuses, which make them ideal for small spaces. Due to their smooth finish, cushion tires struggle on rough terrain but thrive on smoother surfaces inside and outside.   

Pneumatic tires are air-filled or solid tires. Pneumatic tires allow for stronger traction, which works best for rough, outdoor terrain. There are two different types of pneumatic tires: solid and air filled. Solid pneumatic tires are entirely made of rubber, while air-filled pneumatic tires have layers of rubber with air in between. While cushion tires are also entirely made of rubber, solid pneumatic tires have a higher clearance and deeper ridges.   

If you’re operating on smooth surfaces in small spaces, cushion tires are ideal. They allow for maneuverability within your site. If operating in a space with a lot of nails or metal, use solid pneumatic tires which cannot be punctured, thereby promoting higher productivity. If you’re working on uneven and rugged surfaces, air-filled pneumatics provide an easier ride with higher traction. Your work area will help determine the best fit for your needs.  

The standard tynes, or forks, on forklifts are 4 feet, measuring from the end of the tip to the shank, but tynes can be 6 feet or 8 feet as well. The size of the forks depend on the classification and capacity of the forklift.