The Service Truck Body Dictionary:

Revised and Illustrated

Custom Designed

JOMAC crafts customized service trucks based on the unique needs of each individual customer. Built to spec, each utility truck body is created with precision, bringing your blueprint of the perfect work truck to life. We guarantee a service truck body optimized to meet the demands of your work and exceed your expectations of what a service truck can be.

Hand Built

All service truck bodies and cranes are carefully hand-crafted at our Carrollton, OH facility. We do not cut corners with cookie-cutter configurations. JOMAC dedicates the time and effort required to create one-of-a-kind service trucks and cranes, made in the heart of America. Our custom truck body designs and truck-mounted cranes are forged by the hands of our skilled craftsmen. No assembly lines necessary.

Only Al

Aluminum is a durable and light weight solution for the unnecessarily heavy steel service trucks of years past. The forward-thinking engineers at JOMAC build truck bodies using exclusively 6000 series, military grade aluminum. Each aluminum truck body is guaranteed to be rust-free for life. Seriously.

JOMAC Blog » The Service Truck Body Dictionary: Revised and Illustrated
The Service Truck Body Dictionary: Revised and Illustrated

Service truck body

Every industry has their own set of slang that gets used regularly. The world of service truck bodies is no different. While these words may be common to some, to others they seem like a foreign language.

Today we are going to go back to school and teach the meaning for some of this “service truck jargon.”

 Truck Mounted Crane BOOM


This is noise fireworks make. It is also the name of the mechanical arm of a crane. The boom (sometimes called a jib) is the swinging arm that makes a crane, well, a crane.

The boom is the arm of the crane that lifts and places cargo from one area to the other.

Without the boom the crane would not be a crane; it would be just sort of a mechanical box that doesn’t move anything.

The more you know…

 Cab to Axle Measurement

(CA) or Cab-to-Axle

Cab to axel, is exactly that. It is the distance from the center of the rear axle to the back of the truck cab. This dimension is useful to know when specifying the size of service truck body you want to mount on your truck.

Cab-to-axle or (CA) is one of the first metrics you will need to have in mind when seeking a new or used utility truck bed.

 Empty TruckCurb Weight

Curb weight

The curb weight of a service truck body refers to the total weight of the truck, completely empty. To distill this definition more specifically, the curb weight is the total weight of the truck, truck body, and all accessories with nothing loaded in the cabinets, on the deck, and no passengers or drivers in the truck.

The curb weight would be the weight of the truck when you first receive it brand new, without anyone being inside of it.

This is a useful metric to have on hand, as it will allow you to estimate how much weight can be added to the truck without exceeding the payload, and ensuring you are in compliance with DOT restrictions.

 Service truck accessories D Ring


A D-ring is just that. A ring shaped like a capital D.

D-rings can be found on many different service and utility bodies and are quite useful in the realm of strapping cargo on the truck.

 Enclosed service body

Enclosed Service Bodies

An enclosed service body is a type of utility bed option that literally encloses the truck bed floor. Enclosed service bodies are made in several different specification formats.

Common enclosed service body options are roll-up doors vs. swing doors, enclosure height, and chassis type, whether it be a cargo van or heavy-duty truck chassis.


Full Box Design

A full box design is the process of individually fabricating cabinets and welding them together to create an entire truck body. While there are only a few manufacturers that offer this, a truck body with a full box design ensures that each cabinet of the body is built with care and precision, rather than molded as one.

It ultimately creates more durability, as each individual space on the truck body has been designed with care.

JOMAC offers full box designed service truck bodies and you can check those out here.

 knuckle boom crane grapples


When you hear grapples, you may think of Stone Cold Steve Austin opening up a can of whoop a** or The Rock laying the smack down (or maybe that’s just me because I am a perpetual child.)

At any rate, in the service body world, grapples refer to the claws that can be attached to the end of a mobile crane on a truck.

While similar in appearance to the claw seen in those games in restaurant entry ways that allow you to win a cheap stuffed animal, grapples allow cranes to pick up and move cargo and material from point A to point B.

Common grapple types include brick grapples, barrier grapples, debris grapples, clam shell grapples, rock grapples, timber grapples, etc.



GVWR stands for gross vehicle weight rating, and it is an extremely important figure to have in mind when shopping utility trucks.

The GVWR will give you a benchmark for the maximum weight capabilities that the truck can handle when loaded to the max. It is the major differentiator when deciding between trucks to mount a service body on.

Knowing a vehicle’s GVWR will allow you to select the right truck for your utility body and ensure that all functionalities of your work truck can be utilized.

 Knuckle boom crane illustration

Knuckle Boom

While this may sound like a finishing move in an arcade game, it is also the name of a handy type of crane that can drastically make work easier.

The knuckle boom crane has a hinge (or knuckle) on the boom (the actual crane extension) allowing it to extend and retract in one swoop. The benefits of such a crane include quicker loading, more range of motion, and better overall control of the cargo being moved.

 articulating crane Outrigger


The outrigger is a mechanical device that is equipped on most all service truck bodies that come equipped with a crane. The outriggers are two extendable legs that can be moved from their dormant position underneath the truck body out into the open to create security and stability for the service truck while the crane is in use.

 utility truck body roller drawers


Roller Drawer

Roller drawers are simply that. They are modular drawer units fixed on a roller system allowing the drawers to easily slide in and out of a truck body cabinet.

Roller drawers can come in all different shapes and sizes, and they are one of the most useful add-ons to a service truck body, both for their storage and organizational capabilities.


Roll-up Doors

Roll up doors are a service truck body option that have as much dependence on preference as they do function.

Roll-up doors are secured on a track that allows them to “roll up” granting access to the cargo stored within the service body.

They are absolutely necessary for operators that are frequently working in confined spaces that do not allow full function of swing doors (to be covered later in this article).


Swing Doors

The brother/sister of our previous entry, swing doors are doors that swing.

Duh, right?

Swing doors are a service truck body option that are most beneficial to operators that need greater clearance or mobility when accessing their utility truck.

They come in several shapes and sizes and can be customized upon request.

Much like roll-up doors, many choose one or the other based upon preference, while some industries or lines of work necessitate doors to have a swinging function.



A subframe sits on top of the chassis and below the utility truck bed. Its purpose is to provide additional support and structural integrity to the service body which sits upon it.

Subframes are used as an extra line of protection against maximum payloads to ensure that the service body maintains high function while in heavy duty usage.

 aluminum service truck T Latch


Rapper T-Pain’s brother. Not really, though. That was an awful joke.

A T-latch is an option for utility truck box door latches that provide a helpful T-shaped lever to open and latch closed.

T latches provide an operator with a strong grip base to easily open and close heavy-duty utility truck boxes.



Upfitting a truck means to customize it to spec. By upfitting your service truck, you are creating a customized truck body to fit the specific needs of your fleet or business.

JOMAC upfits like nobody’s business.

 service truck Wheel Base

Wheel Base

The wheel base of a service truck is the distance between the center of the front axle and the center of the rear axle.

Another useful metric to have in mind when seeking a new or used utility truck body, the wheel base provides information as to what size of truck bed(s) you will be capable of accommodating.

Additionally, it provides insight when selecting a truck to mount a service body on. As a general rule, longer wheel bases provide more stability and less maneuverability, which is something to take into account depending on your line of work and typical job site scenarios.



A winch is typically used in conjunction with a telescoping mobile crane or on the front/rear of a service truck body.

The winch is a cable with an attachment that provides torque-powered pulling capabilities to the truck/crane or both.

The cable of a winch can be extend and retract, making it useful for fire, rescue and mechanics trucks that need to move other vehicles out of dangerous situations.

When used with a telescoping crane, a winch can be used as an attachment to raise or lower cargo and materials from the head of the boom.



Want JOMAC to upfit your truck body? Click here to learn how.




© 2019 Jomac \ All rights reserved.