I am building rollback bed to my F-450. Bed will roll 3m with bearings, and capasity will be 6000-7000lbs. How strong hydraulic cylinder do i need to pull bed up with load? I found a cheap cylinder for sale, it has 60mm piston and 50mm rod. I´m affraid thats too weak? It has only 8,7 cm2 in pulling side and power is about 2800lbs?

How big cylinders they use in jerr-dan and other small beds?

 

I drove a 95 F-Superduty roll back with an aluminum bed. It had twin cylinders tho to lift up and down as well as twin cylinders to slide front and back. There are alot of factors here beside simply the cylinder sizes. Make sure you factor in the frame length/strength as well as the weight of the actual roll back i.e. steel/aluminum and the advantages of each.

 

I think you also need to factor in the size and gpm hydro pump you use... But that is more a function of the number and size of your cylinders.