Curtain side box truck: how much opening you really get

A curtain side box truck swaps the side walls of a box for heavy fabric curtains on rails. Slide the curtain back and the whole side of the body opens, so a forklift can load or unload from the ground without a dock. The trade-offs are less obvious: the opening is shorter than the body once the curtain bunches up, a center post narrows the box, and the curtain is not the same thing as cargo securement. This guide works through all three using a body builder's own spec sheet.

How a curtain box truck body works

The body has a rigid front wall, a rear frame with a door, a roof and a floor. Between front and rear, the sides are curtains hung from a top rail and pulled tight with tensioners. A removable center support or post helps hold the roof and the curtain line. Morgan's Curtainsider, for example, uses a 28 ounce PVC-coated polyester curtain, ratcheting tensioners at the front, removable center supports and a rear overhead roll-up door.

SOURCE:Morgan Truck Body, Curtainsider spec sheet (04/2019, via dealer document), OCT 2026

How big is the side opening, really?

The headline feature is the side opening, and it is smaller than the body length. Morgan publishes both numbers: the clear opening, and the approximate opening once the curtain is pushed to one end.

SOURCE:Morgan Truck Body, Curtainsider spec sheet (04/2019, via dealer document), OCT 2026

On a 26 ft body, the bunched curtain takes almost 3 feet of the opening. A forklift can still reach every pallet position if you open from the right end, but plan the load so the section behind the bunched curtain is loaded or unloaded from the rear door or after the curtain is moved.

Morgan's sheet is dated April 2019, and it notes that dimensions vary with options; ask the builder for the spec of the body you are buying.

Width, height and the center support

SOURCE:Morgan Truck Body, Curtainsider spec sheet (04/2019, via dealer document), OCT 2026

Two things matter for loading. The center support takes 3 inches of width where it stands, so a load planned to the full 96 inches has to clear it. And the side opening is lower than the inside height by more than 8 inches on every model, so the top of the box is reachable only from inside or through the rear door. Compare those numbers with a hard box: U-Haul's 26 ft truck has 8 ft 1 in of inside width behind a 7 ft 9 in rear door.

SOURCE:U-Haul (page snapshot 2026-09-28, Internet Archive), OCT 2026

What the body weighs

A curtain side body is heavy, and every pound comes out of payload. Morgan lists calculated weights for its 96 inch wide body:

SOURCE:Morgan Truck Body, Curtainsider spec sheet (04/2019, via dealer document), OCT 2026

Put a 26 ft, 97 inch body at 4,464 lb on a chassis rated 26,000 lb, and the chassis itself, fuel and driver still come out of what is left. Weigh the finished truck to learn its real payload.

Curtains and cargo securement

A curtain keeps out rain, sun and prying eyes. It is not automatically a load restraint. Federal rules require cargo to be firmly immobilized or secured on or within the vehicle by structures of adequate strength, dunnage or dunnage bags, shoring bars, tiedowns, or a combination of these.

SOURCE:eCFR, 49 CFR 393.106, OCT 2026

In practice, that means securing the load inside the curtain with straps, load bars or blocking, unless the body builder states in writing that its curtain system is rated as restraint for the load you carry. A pallet that shifts against the curtain in transit can fall when the curtain is opened. See our guides on e-track in a box truck and box truck rails.

Who a curtain side box truck suits

• Building supply and lumber: forklift loading at yards and job sites with no dock.
• Beverage and bottled goods: many drops, each from a different section of the load.
• Palletized freight to sites without docks.

It suits less well when security is critical, when loads are hand-unloaded at homes, or when you mostly load at docks, where a box truck with side door or a standard dry box may do the job with less weight. For other bodies and cabs, see crew cab box truck and cutaway box truck; for sizes, the box truck sizes chart and truck size calculator.

SOURCE:Morgan Truck Body, Curtainsider spec sheet (04/2019, via dealer document), OCT 2026;eCFR, 49 CFR 393.106, OCT 2026;U-Haul (page snapshot 2026-09-28, Internet Archive), OCT 2026;Budget Truck Rental, OCT 2026

Questions box truck owners ask

Q-01What is a curtainside box truck used for?

Freight that is loaded by forklift from the side rather than from a dock: building materials, beverages, palletized goods at yards and job sites. Opening the whole side means a forklift can reach any pallet without working front to back through the rear door, which saves time when a load has many drops.

Q-02Are box truck curtains load-rated?

Do not assume so. Federal rules require cargo to be firmly immobilized or secured by structures of adequate strength, dunnage, shoring bars, tiedowns or a combination. Ask the body builder in writing whether its curtains are rated as cargo restraint; if not, secure the load with straps, bars or other approved means inside the curtain.

Q-03How much does a curtain side body weigh?

Morgan's spec sheet lists calculated body weights from about 3,450 lb for an 18 ft, 85 inch tall body to about 4,930 lb for a 28 ft, 109 inch tall, 102 inch wide body. That weight comes out of the truck's payload, so compare it with a hard-sided box of the same size.

Q-04Curtain side vs box truck: which is better?

A hard-sided box is more secure and simpler to keep weather-tight; a curtain side is faster to load and unload from the side. If your freight is mostly palletized and handled by forklift at yards, the curtain side can pay off. For final mile and residential delivery, a dry box with a liftgate usually fits better.