Logistics & Materials Handling Blog

Forklift Terminology Part 2: Mast Details & Dimensions

by Paul Hinz
Filed under: Forklift Basics

Last week we began our four part Forklift Terminology Series by running through the basic forklift features. We hope everyone has familiarised themselves with the key features and if not, please have a quick look back at last weeks blog Introduction To Basic Forklift Parts as it will help you understand the on going segments. Today’s content will be split up in to two sections concerning terms relating to mast details and dimensions.

Mast Details

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We will now continue to work through some terms specifically aimed at increasing your understanding of the types of forklift masts. Before beginning there are a number of key words you need to be aware of:

  • Lift Height: The height to which the top of the fork is raised when the mast is fully extended.
  • Free lift: Height forks can be raised before the mast extends (i.e. Without increasing mast height)
  • Lowered Height or Collapsed Height: Height from the floor to the top of the mast when it is lowered.
  • Extended Height: the height to the top of the mast or load guard when mast is fully extended.

3 common mast types:

  • Duplex (2 stage): Mast has 2 sections, one outer that does not move and an inner section that raises and elevates the carriage and forks.
  • Triplex (3 Stage): Consists of three sections (one outer and two inner rails). The 2 inner sections raise from outside to in as the mast elevates higher. The mast type provides a shorter lowered height for use through doorways.
  • Quad (4 Stage): consists of four sections (one outer and three inner rails). These sections raise from outside to in, in four sections as the mast raises. Quad masts have the shortest lowered height for its lift and are used where there are very low height restrictions such as container doors.


When discussing dimensions you must be aware of the basic dimension terms such as length, height and width to ensure your forklift fits within the parameters of your factory and floor space. Even though these terms are quite basic, you may not know how to fully apply these terms to your forklift or where to measure from.

Overall length: the measure of a forklift from the front end of the fork arm to the back end of the machine. This is important to know as you need to be aware of how much room is in your factory so the forklift can manoeuvre efficiently and safely.

Overall height: refers to the forklift’s height which is measured from the ground to the highest point on the forklift. This may be the top of the mast or the top of the overhead guard. You must be weary of specific aspects such as deflated tyres or a large overhead guard that rises above the mast. It is essential to know your forklifts overall height to ensure it fits through all doorways within your factory or location.

Overall width: the width of a forklift can vary depending on where the measurements are taken from. Measurements are taken on either side of the machines body from a variety of positions including the axles, fender, fork carriage and tyres so be sure to specify with whoever you are dealing with which point your forklift is being measured from.

The main points to take away from today are that even though these terms can be quite basic, you can never overlook or underestimate them. Even though you may think you know what they mean, if you do a little more research you may realise there’s a bit more to understand and when you are dealing with a large investment such as a forklift, you can never get enough information to make the right choice.