Box truck with side door: sizes, placement and how the doors limit your load

Most box trucks have one way in: the rear door. A box truck with side door adds a second, usually on the curbside, so a driver on a route with many stops can reach the front of the load without unloading the back. This guide covers what a side door looks like on a real body spec, where it goes, how both doors limit what fits, and what to plan before you order one or buy a truck that has one.

What a side door is for

Picture a route with fifteen stops. The first deliveries go in last, at the back. By stop ten, the freight you need is at the front of the box, behind everything else. A side door near the front lets you step in, grab the order and go.

Side doors suit:

• Multi-stop delivery: parcels, food service, beverage and retail routes.
• Trades and service trucks: tools and parts on shelving, reached from the curb.
• Loads split by stop: freight sorted front to back, with the side door serving the front section.

They matter less for single-drop freight loaded and unloaded at a dock.

A real box truck side door spec

Body builders publish side door options in their spec sheets. Morgan's CityMax aluminum body, built for GM chassis in 12 to 16 ft lengths, is a good example:

SOURCE:Morgan Truck Body, CityMax aluminum body specs (GM chassis), OCT 2026

That roughly 40 inch side opening fits a person, a hand truck and a standard pallet side (40 inches) only just. Plan side-door work around cases, totes and hand-truck loads, not pallets. On bigger trucks, side doors are sometimes an option too: Penske lists a curbside door on its 22 to 26 ft box trucks in select markets.

SOURCE:Penske Truck Rental, OCT 2026

Door openings vs the box

Door openings, not box sizes, are where tall freight gets stuck. Published rear-door openings next to inside box dimensions:

SOURCE:Budget Truck Rental, OCT 2026;U-Haul (page snapshot 2026-09-28, Internet Archive), OCT 2026;Budget Truck Rental, OCT 2026;Morgan Truck Body, CityMax aluminum body specs (GM chassis), OCT 2026

Budget lists its 16 ft door as wider than the box's inside width, so the inside width is measured at a narrower point; measure both on any truck. Height is where the published numbers differ most, and the U-Haul 26 footer shows it: a box 8 ft 3 in tall behind a door 6 ft 10 in high. A wardrobe or a stack that stands 7 ft inside the box will not go through that door upright. Measure the door opening of any box truck before you quote tall freight.

Box truck rear door types: roll-up vs swing

• Roll-up door (the box truck overhead door): slides up into the roof on tracks. It opens without swinging out, which helps at tight docks and at the curb, but the rolled-up door and its hardware take some height out of the opening.
• Swing doors: a box truck back door made of two doors hinged at the sides. They open to nearly the full box size and seal tightly, but need room behind the truck and must be latched open.

Upkeep for each is covered in box truck roll-up door and box truck door latch.

Box truck with side roll up door or a box truck sliding door

The Morgan spec above is a hinged single panel. If you want a side roll-up door or a sliding door instead, ask the body builder which side door types they offer for your body length; a door that does not swing out stays clear of the curb and passing traffic when open.

Planning a side door

1. Location: near the front for multi-stop work, so the front of the load stays reachable. On Morgan's spec, the door can be moved in 2 inch steps.
2. Shelving and rails: the door takes wall space. Plan shelving and e-track around it.
3. Opening size: check it against your largest regular item.
4. Steps and grab handles: a side door well above the ground needs a safe way in. See box truck steps.
5. Security: a second door is a second lock to keep up.

Sizes are on the box truck sizes chart, and the truck size calculator checks loads against a box. New to box trucks? Start with what a box truck is.

SOURCE:Morgan Truck Body, CityMax aluminum body specs (GM chassis), OCT 2026;Penske Truck Rental, OCT 2026;Budget Truck Rental, OCT 2026;Budget Truck Rental, OCT 2026;U-Haul (page snapshot 2026-09-28, Internet Archive), OCT 2026

Questions box truck owners ask

Q-01Which side is the side door on a box truck?

The curbside, which is the passenger side in the U.S., so the driver loads and unloads away from traffic. Morgan's CityMax spec, for example, lists the side door location on the curbside and lets the buyer move it fore and aft in 2 inch steps from a standard position.

Q-02Can you add a side door to a box truck?

A side door for box truck bodies can be added after the fact, but it means cutting into the body wall, which is part of the box's structure and holds its rails. Have a truck body shop or the original body builder do it, and ask what reinforcement the opening needs. A box truck side door kit sold online still needs that structural work done right.

Q-03Is a roll-up or swing rear door better?

Roll-up doors open without swinging out, which helps at tight docks and curbs, but the rolled door takes headroom at the top of the opening. Swing doors open the full height and width but need clearance behind the truck. Our roll-up door guide covers maintenance and repair.

Q-04How big is the rear door on a 26 ft box truck?

Smaller than the box. Budget lists 7 ft 10 in wide by 7 ft 7 in high for a box 8 ft 1 in wide and tall inside, and U-Haul lists 7 ft 9 in by 6 ft 10 in for a box 8 ft 3 in tall. Measure tall items against the door, not the box.