Forklift forks are classified according to the Industrial Truck Association (ITA) carriage class system. These standardized classes determine which forks will properly mount to your forklift's carriage and what loads they can safely handle. Understanding fork classes is essential for replacement forks, attachments, and safe operation.
What Are ITA Fork Classes?
ITA fork classes, also known as hook-type forks, are the most common fork mounting system in the material handling industry. They attach to the forklift carriage via top and bottom hooks that latch onto horizontal carriage bars, simplifying installation and replacement without the need for bolts. These forks are standardized under ISO 2328, ensuring compatibility across different forklift manufacturers.
The 5 ITA Fork Carriage Classes
Fork classes correspond directly to carriage classes. Each class is defined by carriage height and lifting capacity.
Class Carriage Height Lifting Capacity Typical Application
Class I 13 inches Less than 2,200 lbs Very light-duty electric pallet trucks or small walkie stackers
Class II 16 inches 2,200 – 5,500 lbs Common for indoor forklifts, narrow aisle, and warehouse use
Class III 20 inches 5,500 – 10,998 lbs Standard for many mid-size IC or electric forklifts
Class IV 25 inches 11,000 – 17,600 lbs Heavy-duty outdoor or industrial forklifts
Class V 28.66 inches 17,602 – 24,198 lbs Very heavy-duty forklifts used in ports, steel yards, etc.
Note: Some sources show Class III capacity up to 10,998 lbs, while others state 10,000 lbs. Always verify with the forklift's data plate for exact specifications.
Additional Fork Variations
Beyond the five primary classes, there are less common variations:
Class B – Used for piggyback forklifts or European narrow aisle forklifts
Type A vs. Type B – Type A is the most common and used for both indoor and outdoor applications. Type B is primarily used with outdoor lift trucks.
How to Determine Your Forklift's Fork Class
Measure the carriage height – Measure the distance between the top and bottom carriage bars.
Compare to the class chart – Match your measurement to the class specifications above
Consult the data plate – The forklift's capacity plate provides the most reliable information for exact specifications and limitations
Verify fork compatibility – Ensure replacement forks match both the class and rated capacity of your forklift
How Fork Dimensions Relate to Class
Fork dimensions are typically expressed as Thickness × Width × Length (e.g., 1½″ × 4″ × 42″).
Class Typical Width Typical Thickness Common Lengths
Class II 4 inches 1.4 – 1.7 inches 42", 48"
Class III 5 inches 1.75 – 2 inches 42", 48", 54"
Class IV 6 inches 2+ inches 48", 54", 60"
Class V 6+ inches Heavy-duty 60", 72", 96"
Pin-Type Forks: The Exception
Not all forklifts use ITA hook-type forks. Some older or larger forklifts use pin-type forks, which attach via a pin or shaft. Pin-type forks do not follow any standard dimension or carriage fitting standard. If your forklift uses pin-type forks, you will need to measure your existing forks or consult the manufacturer for proper replacements.
The Bottom Line
Forklift fork classes are standardized by the ITA under ISO 2328, with five primary classes (I through V) defined by carriage height and lifting capacity. Class II (16", 2,200-5,500 lbs) is the most common for indoor warehouse forklifts, Class III (20", 5,500-10,998 lbs) for mid-size IC and electric forklifts, and Class IV (25", 11,000-17,600 lbs) for heavy-duty industrial applications. To determine your class, measure the carriage height and consult your forklift's data plate. Always ensure replacement forks match your forklift's class and rated capacity for safe operation.