A pallet and its handling equipment form one system: the pallet must offer openings that are wide, tall and deep enough for the forks, and the forks must be able to lift the pallet's load without damaging its boards. Most compatibility problems come down to three numbers: the fork opening height, the fork opening width and the length of the forks relative to the pallet.
How forks meet pallets
A counterbalance forklift or reach truck carries two tines (fork arms) hung on a carriage. The carriage dimensions are standardized internationally in ISO 2328, Fork-lift trucks — Hook-on type fork arms and fork arm carriages — Mounting dimensions, so that forks from different makers fit the same truck class. The tines are adjustable sideways, which lets one truck serve pallets with different opening spacing.
A manual or powered pallet jack (also called a pallet truck or hand pallet truck) works differently. Its two forks are fixed to a chassis, with load wheels at the tips and a hydraulic pump in the handle. Because the wheels sit inside the fork, the fork is thicker at the tip than a forklift tine, and the lowered fork height is the critical figure.
| Feature | Forklift tines | Pallet jack forks |
|---|---|---|
| Typical tip shape | Tapered, thin tip | Blunt, roller or wheel at tip |
| Lowered height | Not applicable, tines rest on floor | Commonly about 75–90 mm (3–3.5 in), model dependent |
| Overall width across forks | Adjustable | Fixed, commonly 520–685 mm (20.5–27 in) |
| Lift height | Metres | Typically 100–200 mm |
| Best use | Loading, racking, stacking | Short horizontal moves, retail, delivery |
Fork lengths vary by model. Forks of about 1150–1200 mm are common for 1200 mm pallets, and shorter forks exist for small pallets and for use inside containers.
Opening dimensions that matter
Every pallet design has fork openings whose size follows from its construction. Three dimensions decide compatibility:
- Opening height. The clear space between the floor and the underside of the top deck, or between stringer boards. A jack whose lowered height is greater than the opening simply cannot enter.
- Opening width. The gap between supports. The forks must fit with a few centimeters of clearance on each side, and forks spread too wide will strike blocks or stringers.
- Entry sides. Two-way pallets accept forks from two opposite sides only; four-way pallets accept them from all four. See two-way vs four-way pallets.
The EPAL Euro pallet is a four-way block pallet with a height of 144 mm (5.7 in) and 78 mm blocks. Its openings are shallow compared with older stringer pallets, which is why standard pallet trucks must have a low lowered height and tapered tips to enter without lifting the pallet by accident. Wide North American stringer pallets such as the 48 × 40 in (1219 × 1016 mm) pallet offer taller openings of about 89 mm (3.5 in) but only two-way entry through the stringer sides, with partial four-way access via notches. The standards are described in the EPAL Euro pallet guide and the 48 × 40 in pallet guide.
Bottom deck design and pallet jacks
Pallet jacks put their load wheels on the floor under the pallet. If the bottom deck has a board directly where the wheel travels, the wheel can strike the board's edge and either stop or lift it. Designers avoid this in three ways:
- Chamfered bottom lead boards or tapered lead edges, so the wheel rides up and over.
- Spaced bottom boards with gaps wider than the wheel.
- Open-ended bottom decks such as stringer pallets with no bottom boards under the fork path.
Missing, split or loose bottom lead boards are one of the most common repair reasons for pallets in circulation, because the jack wheels hit exactly those boards. Repair categories are discussed in pallet repair.
Load, center of gravity and fork length
Forks that are too short for a pallet put the load's center of gravity outside the fork length, causing dips and tipping hazards. A widely used rule is that the forks should extend at least two thirds of the way beneath the load, and ideally the full depth of the pallet without protruding. Forks that are too long can pierce the opposite deck on a stacked load or strike a second pallet behind the first.
Forklift capacity ratings decrease as the load center moves away from the carriage face. The rated load center on standard trucks is 500 mm (20 in) from the heel of the fork; a pallet load exceeding this depth reduces the allowed lift. Use the truck data plate, not the pallet label, to decide what can be lifted.
Pallet load ratings are a separate set of numbers: static, dynamic and racking capacity, covered in pallet load capacity. A pallet can be rated for more than the truck can safely lift, and the reverse.
Compatibility checklist
Before specifying a pallet for a site, check:
| Question | What to verify |
|---|---|
| Do the forks fit? | Opening height versus lowered fork height of the pallet jacks in use |
| Are four-way entries needed? | Cross-docking and narrow aisles often require them |
| Does the bottom deck help jacks? | Chamfers or spaced boards at the lead edge |
| Is fork length right? | Forks cover at least two thirds of the pallet depth |
| Are racking beams compatible? | Support span, overhang and rated racking capacity; see pallet racking systems |
| Is the weight handled safely? | Truck capacity at the actual load center |
Specialist equipment broadens the options: double-pallet jacks with long forks move two pallets at once, scissor lift tables raise pallets to working height, and clamp attachments grip loads without forks, though these need a pallet-free load or a slip sheet. Plastic and metal pallets generally offer more consistent openings than worn wooden pallets, which may be damaged or deformed.
Safety points
Fork contact is a leading cause of pallet damage and a frequent cause of near-misses. Operators should enter squarely, avoid pushing forks against board edges, and never lift a pallet with a damaged lead board. Loads above the rated lift height of a hand jack should not be raised manually. Equipment should be inspected daily, with checks on forks, hydraulics and wheels, in accordance with national workplace regulations.
Frequently asked questions
Why will my pallet jack not enter a Euro pallet?
The most common cause is a lowered fork height or tip wheel that is taller than the pallet's fork opening, or a bottom board that blocks the wheel. Choose a jack designed for low-profile pallets and inspect the lead boards.
How far should forks extend under a pallet?
Forks should reach at least about two thirds of the pallet's depth and ideally nearly the whole depth, without sticking out far beyond the far edge. Short forks cause tipping and increase board stress.
What does ISO 2328 cover?
It defines the mounting dimensions of hook-on fork arms and fork arm carriages, so that forks from different makers fit trucks of the same carriage class. It does not set pallet dimensions.
Sources
- ISO 2328:2011 Fork-lift trucks — Hook-on type fork arms and fork arm carriages — Mounting dimensions — Standards Council of Canada
- EPAL Euro Pallet (EPAL 1) technical data — European Pallet Association
- How Much Load Can My Pallet Carry? — Virginia Tech Center for Packaging and Unit Load Design
- ISO 445:2013 Pallets for materials handling — Vocabulary — International Organization for Standardization