1.3 Reading the data plate
The data plate is the only place on the truck where the manufacturer tells you, in writing, how much you may lift and under what conditions. 1910.178(a)(6) makes keeping it legible a legal duty, and 1910.178(o)(2) makes staying inside it a legal duty. Most operators glance at one number on it. There are at least six that matter.
1 What is on the plate
Layouts differ by manufacturer, but the same information appears on every counterbalanced truck. Read it once carefully on your own machine and the rest of Part 2 will make sense immediately.
| Field | What it means | Why it matters |
|---|---|---|
| Model and serial number | Identifies this exact truck | Ties the truck to its manual, its parts and its inspection history |
| Truck weight | Weight of the truck itself, usually without load | Decides whether a dock plate, trailer floor, elevator or slab can carry you |
| Rated capacity | Maximum load weight, at a stated load center and a stated maximum lift height | The number 1910.178(o)(2) makes binding — and it is a package, not one figure |
| Load center | The distance the capacity assumes, typically 24 in on trucks up to 30,000 lb | Grow the load center and the capacity falls; Chapter 2 of Part 2 does the arithmetic |
| Maximum lift height | The height the rated capacity applies to | Many trucks are derated above a stated height; the plate carries the schedule |
| Attachment information | Attachment fitted, and the truck-plus-attachment capacity | Required by 1910.178(a)(5) when the attachment is not factory installed |
| Fuel type and designation | D, DS, DY, E, ES, EE, EX, G, GS, LP or LPS | Decides which locations the truck may enter — Part 4, Chapter 1 |
| Tire type | Cushion or pneumatic, and the size | Changing tire type changes the truck's geometry and its capacity |
2 Capacity is a sentence, not a number
"It is a five thousand" is the most common sentence on a warehouse floor and one of the most misleading. The plate does not say 5,000 lb. It says something closer to: 5,000 lb at a 24-inch load center, to a maximum fork height of 187 inches, with these forks, on these tires, with the mast vertical.
Change any of those conditions and the number changes with it. A load whose center of gravity sits 36 inches out from the fork face is not a 24-inch load center load, and the truck's honest capacity for it is lower — often dramatically. A load lifted above the plated height may be outside the rating entirely. Appendix A to 1910.178 states the operator's obligation directly: to safely operate the vehicle, the operator should always check the data plate to determine the maximum allowable weight at the rated load center.
3 Attachments change the plate
A side shifter, a carton clamp, a paper roll clamp, a fork positioner, a rotator, a drum handler — each one adds weight ahead of the front axle and usually pushes the load further forward. Both effects eat capacity, and the truck no longer performs like the machine on its original plate.
1910.178(a)(5) handles this: if the truck is equipped with front-end attachments other than factory installed attachments, the user shall request that the truck be marked to identify the attachments and show the approximate weight of the truck and attachment combination at maximum elevation with load laterally centered. That is a duty on the user, not on the manufacturer, and it is one of the most commonly skipped requirements in the standard.
1910.178(a)(4) is the harder-edged companion: modifications and additions which affect capacity and safe operation shall not be performed by the customer or user without the manufacturer's prior written approval, and the capacity, operation and maintenance instruction plates, tags or decals shall be changed accordingly. Welding a longer set of forks onto a carriage, fitting a boom, adding counterweight — all of it needs written approval first, and a corrected plate afterward.
4 Fork length, fork condition and the load you can actually take
Forks are wear items and they are rated. Each fork carries its own marking from the manufacturer, and a pair should be matched — same length, same thickness, same manufacturer, same rating. A mismatched pair changes how the load sits and how the weight is shared.
Two conditions take a fork out of service and both are worth learning by eye. Wear at the heel — where the vertical shank meets the horizontal blade — thins the steel exactly where the bending stress is highest, and a worn heel is the classic reason a fork lets go under a load it carried yesterday. Any bend in the blade, any crack, any deformation of the top hook, and the fork is finished: a bent fork does not go back to straight and it will not be re-rated. Your manufacturer's manual gives the wear limits and the inspection interval for your forks; that document, not a rule of thumb, is the authority.
Fork length matters for a different reason. 1910.178(o)(5) requires the load engaging means to be placed under the load as far as possible, and then the mast to be carefully tilted backward to stabilize the load. Forks too short to reach under a pallet leave the load's center of gravity further out than it needs to be, which is the load center problem of Part 2 arriving through the back door.
5 A worked example
Appendix A gives the arithmetic and a worked case, and it is worth walking through here because the rest of Part 2 depends on it. A-5.3 states: if an operator is operating a 3,000 pound capacity truck with a 24-inch load center, the maximum allowable load-moment is 72,000 inch-pounds — 3,000 times 24. If a load is 60 inches long, so its center of gravity sits 30 inches out, then the maximum that load can weigh is 2,400 pounds, that is 72,000 divided by 30.
- 1Read the plate. Capacity 3,000 lb at a 24 in load center.
- 2Compute the truck's allowable load moment. 3,000 lb x 24 in = 72,000 in-lb.
- 3Find the real load center. For a uniform load 60 in long, the center of gravity is at the middle: 30 in from the fork face.
- 4Divide. 72,000 in-lb / 30 in = 2,400 lb. That is the most this load may weigh — a 20 percent cut from the plate figure.
Appendix A adds a note that keeps this honest: because the true load-moment distance is measured from the front wheels rather than from the fork face, calculating with the load-center distance always produces a lower allowable moment than the truck was designed to handle. The method is conservative on purpose, and it is the method the standard puts in front of operators. You can run the same arithmetic on our forklift load center and capacity calculator instead of doing it in your head.
6 When the plate is missing or unreadable
This has a single correct answer: the truck does not run. 1910.178(a)(6) requires the user to see that all nameplates and markings are in place and maintained in a legible condition, and without the plate there is no lawful way to comply with 1910.178(o)(2), which allows only loads within the rated capacity of the truck to be handled. Guessing the capacity from a similar machine in the next bay is not compliance — and the two trucks may differ in tires, mast, attachment or counterweight.
Report it the same way you would report a brake fault, through the same channel Chapter 4 covers. Manufacturers will supply a replacement plate against the serial number, which is exactly why the serial number field is on it.
- Rated capacity is a package: a weight, at a stated load center, to a stated maximum lift height, with stated forks and tires.
- 1910.178(o)(2) allows only loads within the rated capacity; Appendix A tells the operator to check the plate for the maximum weight at the rated load center.
- Non-factory front-end attachments must be marked under 1910.178(a)(5) with the truck-and-attachment weight at maximum elevation, load laterally centered.
- Capacity-affecting modifications need the manufacturer's prior written approval, and the plates must be changed to match — 1910.178(a)(4).
- Allowable load moment = plated capacity x plated load center; divide by the real load center to get the real limit.
- A missing or unreadable data plate takes the truck out of service; there is no compliant way to guess the number.
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