Measuring forklift forks is essential for selecting replacements, verifying compatibility with your carriage, and inspecting for dangerous wear. Fork dimensions are typically expressed in the order Thickness × Width × Length—for example, 1 ½” × 4” × 42” .
The Three Primary Dimensions
Fork Length
Measure from the tip of the fork to the front face of the heel (where the fork meets the carriage) . This is the horizontal distance the fork extends forward. Forks should extend at least two-thirds the length of the load to ensure stability . Standard lengths include 1,219mm, 1,829mm, and 2,438mm .
Fork Width
Measure the fork across the face of the blade from side to side at its widest point, closest to the shaft . Standard width for Class II forks is generally 4 inches; for Classes III and IV, typical widths are 5 and 6 inches, respectively .
Fork Thickness
Measure the thickness along the heel or the vertical part of the fork (the shank) . Use the back side of the fork rather than the bottom because the bottom wears down from use . The most common thickness is 1 ½ inches, but other standard sizes include 1 ¾”, 2”, and 2 ½” .
Important: For full tapered forks, measure within 2 inches of the heel .
Critical Wear Inspection: The 10% Rule
The heel of the fork is the first component to wear out . ANSI/ITSDF and ISO 5057 standards require that heel wear must not exceed 10% of the original thickness. A 10% reduction in fork thickness results in a 20% reduction in operating capacity .
How to measure heel wear:
Use a caliper (digital, Vernier, or a dedicated fork wear caliper)
Measure the nominal thickness “N” on the fork shank
Position the caliper at the end of the heel internal radius, where wear is highest
If the fork enters the slot corresponding to the nominal dimension, wear exceeds the safety limit and the fork must be replaced
Additional Measurements and Checks
Fork Angle
The angle between the shank and the blade must be within 87 and 93 degrees . Deviation beyond 3 degrees requires replacement.
Fork Spread
Measure the distance between the inner surfaces of the two fork tines to ensure they are symmetrical and properly spaced .
Hook Clearance and Condition
Inspect the latches that attach the fork to the carriage and measure the distance between the top of the fork and the bottom of the carriage hook to ensure proper engagement and security .
When to Replace Forks
Replace forks immediately if any of the following are detected:
Heel wear exceeds 10% of original thickness
Fork angle exceeds 93° outwards or 87° inwards
Visible cracks, bends, or twists in the blade or shank
Fork tips worn beyond acceptable limits
Bent fork toe
Never attempt to bend or weld forks back into place—they must be replaced .
The bottom line: Fork dimensions are measured as Thickness × Width × Length. The critical safety measurement is heel wear, which must not exceed 10% of original thickness—beyond that point, the fork's load capacity drops by 20% and the fork must be replaced. Use a caliper for accurate measurements, and always inspect forks in pairs .