By The Hazli Family — Peter & Louise · November 1, 2026
Quick answer: A foam mattress is one of the easiest beds to put in a truck because the bed floor is flat and rectangular and foam bridges the ribs on its own. The work is in three places: the wheel wells (measure between them and buy to that width, not the width at the tailgate), the weather (you need a cap, a topper or a bed tent, and a layer under the mattress on cold nights), and the mattress itself (unroll it early so it expands, and lay a rubber mat under it so it does not creep toward the tailgate).
Our car camping bed guide covers the truck bed in one section. This post goes deeper on the truck-specific parts. For the material, see the memory foam camping mattress guide.
Why foam suits a truck bed
An air bed in a truck bed has three enemies: the ribs in the floor, the cold metal under it, and the latches, tie-down hooks and liner edges that can puncture it. A foam mattress spans the ribs, puts a layer between you and the metal, and has no air to lose.
The costs are the usual ones for foam. It is heavier and bulkier than an air bed, it takes bed space while you drive, and it needs time to expand after you unroll it. In a truck, the bulk matters less than in a hatchback, because the bed is where gear goes anyway, and the mattress can ride flat with soft bags on top.
Measure between the wheel wells
This is the number that decides the size. The mattress has to fit the narrow part between the wheel wells unless you want it tilted on one well all night. We do not list truck bed dimensions because they vary by make, model year, cab and bed length; a tape measure gives you the right number in a minute.
- Width: measure across the bed floor between the two wheel wells. That is your maximum mattress width.
- Length: measure from the front bulkhead to the inside of the closed tailgate.
- Height: if you have a cap or topper, measure from the bed floor to the underside of the cap. Subtract the mattress thickness and ask whether you can still turn over and sit up on an elbow.
Then pick the widest Hazli size whose width is at or under your wheel-well number: Single (75 × 30 × 3 inches), Twin (75 × 36 × 3), Twin XL (80 × 40 × 4) or Queen (80 × 60 × 4). The camping mattress sizes guide has the full table. For two adults, two narrower mattresses side by side can work better than one wide one.
Tip: The strip of floor outside each wheel well is wasted for sleeping but handy for storage. Bins, a water jug and boots can live there.
Ribs, liners and keeping it in place
- Ribs: a three-inch or four-inch foam mattress bridges them on its own. A thin pad does not.
- Spray-in liner: fine as is. It is grippy, which helps the mattress stay put.
- Drop-in plastic liner: slippery, so the mattress can creep on a slope. Put a loose rubber mat or a rug under it.
- Bare metal or paint: add a rubber mat for grip and to keep the cover off any grit.
- Tie-down hooks and cleats: note where they are so you do not put your knee on one getting in.
Park with the nose slightly uphill so your head is high and the mattress stays against the bulkhead.
Cap, topper or bed tent
You need something over the bed.
Cap or topper
A hard shell that fits to the bed rails. It is usually the best bedroom of the options: weather protection, windows for air, and no setup each night. Headroom is the limit, so check the floor-to-cap height before you decide on a four-inch mattress. Cracking the rear window and one side window helps airflow. Fit bug screen to the windows you leave open.
Bed tent
A tent made to fit the bed. More headroom than a cap, and it comes off when you need the truck for work. The downsides are setup each night and less protection in sideways rain. Keep the mattress within the tent floor so the ends are not pinched by the zipper.
Tonneau cover
A tonneau is for hauling, not sleeping. There is little headroom and little airflow.
If you own a cap, that is the answer. If you do not, a bed tent gets you camping this weekend.
Weather: rain from above, cold from below
Rain. With a cap, check the tailgate seal by hosing the back and looking for drips. With a bed tent, a few drips at the seams can happen in a hard rain, which is where a waterproof mattress cover helps. The Hazli cover is waterproof, removable and machine washable.
Cold. A truck bed is a metal tray in the open air. On cool nights put a layer under the mattress: a closed-cell pad, a wool blanket or a rug over the rubber mat. We do not publish temperature or insulation ratings, so treat this as a comfort step. Memory foam can feel firmer when it is cold and softens as it warms; our post on memory foam in the cold covers what to expect.
Heat. A cap in the sun gets hot by mid-morning. Open the windows before you leave for the day and use a reflective sunshade if you plan to nap in it.
Condensation. Two people breathing under a cap put a lot of moisture on the glass. Crack two windows, keep wet gear in the cab, and in the morning drop the tailgate for ten minutes while you make coffee.
Tip: Leave the mattress flat in the bed between stops on a multi-day trip. Stack soft bags on it rather than hard boxes, and it stays expanded and ready when you park.
Setup, in order
- Park nose-up. Drop the tailgate.
- Lay the rubber mat between the wheel wells; add a blanket or closed-cell pad on top if the night will be cool.
- Unroll the mattress onto it right away so it has time to expand.
- Pitch the bed tent, or open the cap windows and fit the screens.
- Fitted sheet, your pillows, a quilt or an unzipped bag. Bins and boots in the strips outside the wheel wells.
- Close the tailgate. Crack two windows. Lights off.
Our recommendation
For a truck bed, the mattress we recommend is the Hazli Matrix Air-Cell memory foam camping mattress. It was named Best Camping Mattress in the USA for 2025 by Best of Best Review. Six sizes, from Kids to Queen, so you can match the gap between your wheel wells. The cover is waterproof, removable and machine washable, which in a truck means road dust and a wet dog are a wash cycle at home. Every Hazli product is CertiPUR-US and OEKO-TEX certified.
The trade-offs: it is heavier and bulkier than an air bed, it takes bed space while you drive, and it needs time to expand after unrolling. You have 30 days from delivery to decide. It is sold here, on Amazon US and on Amazon Canada. Measure between your wheel wells, then pick from the memory foam camping mattress collection.
