How to Determine Turn Radius for Forklifts

A forklift's turning radius, also known as the turning circle, is vital information for a machine operator to have, in order to determine how much space is needed to turn the forklift around. A tighter turning radius enhances the forklift's maneuverability, allowing it to work in more congested and restricted areas. Operators unaware of this measurement may cause damage to the machine or property.

Things You'll Need

• Forklift
• Flat ground surface
• Water hose or spray bottle
• Tape measure
• Calculator

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Instructions

• 1

  Prior to testing, check the steering geometry alignment and correct it if necessary.

• 2

  Begin the test with the trained operator in the cab to control the functions of the machine, and a second person on the ground wetting the inside and outside wheels of the unit with a hose or spray bottle.

• 3

  Drive the machine in a complete circle with the wheels turned to the maximum cut angle, repeating once. Continue to wet the wheels as necessary.

• 4

  Once completed, measure the watermarks left by the tires with a tape measure, from the midpoint of the tire mark to a similar point across the diameter of the circle. For the outside turning diameter, measure the watermark left by the outside tires from one side to the opposite side of the circle. The inside turning diameter can be determined by stretching the tape measure across the circle left by the interior tires.

• 5

  Divide these numbers in two to come up with the turning radius. Note the turning center is the midpoint of the circle's diameter.

• 6

  Determine the wall-to-wall turning diameter by dropping a plumb line from the extreme outside radial extension on the vehicle and locating the point on the pavement directly below. This point to the turning center indicates the vehicle clearance radius; wall-to-wall turning diameter is twice the vehicle clearance radius.