Forklift attachment manufacturers offer online calculators to estimate the safe lifting capacity when using a particular attachment. However, only the forklift truck manufacturer can give accurate lifting capacities. Before installing any attachment contact your local authorized dealer of your forklift brand and ask them to begin re-rating your lift according to the attachment you want to install. Once re-rated the forklift should have a new factory authorized specification plate, to replace the original plate, installed showing the new rating for the lift.