Meagan Daugherty

A roll-off subframe is an engineered frame design that is used to make non-roll-off bodies or equipment compatible with roll-off trucks. Sometimes called skids, rail frames and long rails, these structures are the base for whatever you want to haul with your roll-off truck.

When purchasing a roll-off truck, the most common styles you can purchase is a cable style hookup, operated with a winch and hook system that pulls the body onto the truck, or a hooklift style hookup, operated with a hook mechanism that hooks under a hooklift pin and lifts the container onto the system. Most cable style systems have universal cable hookup that allows them to operate with most manufacturers standard build roll-off containers with a cable hook. Hooklift systems, however, can differ between hook heights, hooklift pin sizes, and stop locations (Read “Hooklift Stop Locations – What are they and how to measure them?” for more information).

Just as there are containers that fit both systems, there are also roll-off subframes that can be manufactured with either a cable, hooklift, or cable/hooklift combo style hookup. If your truck is a hooklift, or you plan to utilize multiple trucks that differ between hooklift and cable systems and need a combo hookup, you as the buyer will need to give the subframe manufacturer more information to get the best fit for your truck. This includes the hook height, sometimes known as bail height.

Hook height is the measurement from the bottom rail of the frame to the middle of the hooklift pin. This allows the hook to pick up the container, properly and safely, by the hooklift pin and be loaded onto the truck. The hooklift pin can also differ in sizes, commonly found in 1 ½”, 2”, and 2 ½” diameters.

Here are some tips that you can follow to provide the most accurate hook information to the manufacturer:

1. Know your hooklift system model information – Sometimes subframe manufacturers have dealt with that model and already know the proper measurements, however, don’t rely on that alone as some may have several different options that will need to be confirmed. It is always best to measure yourself for the best possible outcome.

2. Use an accurate tape measure

3. Measure in inches

4. Follow the diagrams below to measure both the hook height and determine which hooklift pin diameter and location you will need.

a. Regardless of your hooklift system, there will be these three measurements needed to properly measure and provide to the subframe manufacturer.

1. Bottom of the hook arm to the bottom of the pin opening. This measurement determines the hook height that you will need on your subframe. Common measurements are 36”, 54”, and 62”.

2. Diameter of the pin opening. This measurement determines whether you will need a 1 ½”, 2” or 2 ½” hooklift pin. 1 ½” pins are mostly seen on a 36” hook height, whereas a 2” or 2 ½” pin can be interchanged based on measurements for a 54” or 62” hook height.

3. Back of the pin opening to the back of the hook arm. This measurement determines if you will need a specialized pin placement on the subframe. This measurement varies based on your hooklift system, many ranging from 5 ½” to 14”.

5. Review the sales order before you sign off – Be sure to review based on your measurements and let them know if anything is incorrect before the subframe is built and let the sales representative know if any changes need to be made.

Following the three required measurements and the five tips above, you can get your hooklift measurements right the first time. This will also help avoid having to make time to complete unnecessary modifications and adjustments both for you and the subframe manufacturer.