Quick answer: Every forklift attachment lowers the truck’s usable capacity, because it adds weight and pushes the load farther forward. Before you put an attachment to work, get the capacity with that attachment from your forklift dealer or the manufacturer and make sure the truck’s capacity plate shows it.
Why attachments reduce capacity
A forklift is balanced like a seesaw, with the front wheels as the pivot. The counterweight at the back offsets the load at the front. A forklift’s rated capacity assumes a load sitting at a set distance from the fork face, called the load center. For many common forklifts that distance is 24 inches.
An attachment changes that balance in two ways:
- It adds weight at the front. The attachment itself uses up part of the truck’s capacity before you pick anything up.
- It moves the load forward. A clamp, rotator or positioner sits between the carriage and the load, so the load’s center ends up farther from the front wheels. The farther forward the load, the less the truck can safely lift.
The result is often called the truck’s net capacity, derated capacity or capacity with attachment. It is always lower than the capacity on a bare-fork truck.
What determines capacity with an attachment
| Factor | Why it matters |
|---|---|
| Attachment weight | Heavier attachments take more of the truck’s capacity before the load is added. |
| Attachment center of gravity | Where the attachment’s own weight sits affects the truck’s balance. |
| Effective thickness | How far the attachment moves the load forward from the carriage. |
| Load size and shape | Large or deep loads have a load center farther out than the standard rating. |
| Lift height and mast | Capacity can drop at higher lift heights, depending on the mast. |
Your forklift dealer or the truck manufacturer uses these numbers to calculate capacity with the attachment. We can provide the attachment specs for any unit we rent or sell.
Update the capacity plate
OSHA’s forklift standard (29 CFR 1910.178) requires the manufacturer’s approval for changes that affect capacity and safe operation, and requires capacity plates to be changed to match. In practice, when an attachment is added, the forklift’s data plate should be updated to show the capacity with that attachment. Your forklift dealer can handle this.
How to choose an attachment with capacity in mind
- Start with your heaviest load. Know the weight and size of the heaviest load you need to move.
- Match the attachment to the truck. Check carriage class, hydraulic functions and the truck’s rated capacity.
- Ask for the capacity with attachment before you buy or rent. If it is too low, you may need a larger truck or a lighter attachment.
- Train operators. Make sure drivers know the new capacity and how the attachment changes handling.
Not sure what fits? Send your forklift make, model and capacity with your quote request or rental request, and we will help match an attachment to your truck. Choosing a specific attachment? See our guides to carton clamps, paper roll clamps and fork positioners.
Frequently asked questions
How much capacity does a forklift attachment take away?
It depends on the attachment’s weight, center of gravity and effective thickness, and on the truck. Your forklift dealer can calculate the exact capacity with the attachment installed.
Do I need a new capacity plate when I add an attachment?
Yes. The forklift’s capacity plate should show the capacity with the attachment. Your forklift dealer can provide an updated plate.
Does a side shifter reduce capacity?
Yes. Any attachment, including a side shifter or fork positioner, adds weight and moves the load forward.
Where can I find an attachment’s weight and center of gravity?
On the attachment’s serial plate and in the manufacturer’s specifications. Call us with the model and serial number and we will look it up.
Need help matching an attachment to your forklift?
AttachCo rents and sells reconditioned forklift attachments, shipped nationwide through your forklift dealer. Tell us about your truck and your loads and we will recommend the right unit.