The Gladiator JT's 5-foot bed is one of the truck's biggest selling points — a real cargo space on a real off-road platform. Protecting it correctly depends on how you use it.
The factory JT bed is stamped steel with a basic painted finish. Haul lumber, gear bags, recovery equipment, and firewood over a few seasons without protection and the bed floor starts rusting through paint chips at scratch points. The right liner depends on whether you're protecting paint, improving grip, dampening road noise, or all three.
**Spray-in liner (professional):** A pro spray-in (Line-X, Rhino Lining, or Sherwin-Williams truck bed coating) is the most durable option. The shop scuffs the surface, masks the bed rails, and sprays a textured polyurethane coating that bonds chemically to the steel. Thickness is typically 1/4" and the texture provides excellent grip. Cost: $450–600 at most shops. Lifetime coverage. The downside: once it's on, it's permanent — and it adds weight (typically 15–20 lbs for a JT-size bed).
**DIY roll-on liner:** Herculiner and Durabak produce roll-on versions of the same polyurethane chemistry at a fraction of the cost. Prep work is the limiting factor — the bed surface must be clean, dry, degreased, and scuffed with 80-grit sandpaper for the coating to bond correctly. A properly prepared DIY roll-on holds up well; a rushed prep job peels within a year. Durabak 18 is thicker and more resilient than Herculiner and is the preferred choice for builds that see real trail use.
**Drop-in liner:** Plastic drop-in liners (Westin, Husky, Access) protect paint but trap water and debris underneath, which accelerates rust over time. They're also prone to shifting under load. On a truck used primarily for hauling or as a daily, a drop-in is acceptable. On a rig that lives in wet environments or sees seasons of trail use, avoid them.
**Bed mat:** BedRug and DualLiner mats are a compromise — removable, won't trap water as aggressively as a drop-in, and provide surface protection without the permanence of a spray-in. The BedRug IMJ20SBS is custom-fit to the JT bed including the tailgate and works well for overlanders who regularly rearrange the bed contents and need something they can pull out to clean.
**The JT bed dimensions:** 60" long x 53.5" wide between the wheel wells x 20.3" deep. The Gladiator Sport and Sport S run the same 5-foot bed as all JT trims — bed size doesn't change by trim level.
1. Remove any accessories from the bed — tie-down cleats, cargo rails, drain plugs.
2. Wash the bed thoroughly with soap and water, rinse, and let dry completely. Any surface moisture causes adhesion failure.
3. Sand the entire bed surface with 80-grit sandpaper to scuff the paint. Don't skip wheel wells or corners. The goal is a uniform matte surface with no gloss remaining.
4. Wipe down with degreaser (acetone or wax-and-grease remover). Let flash dry for 15 minutes.
5. Mask the top bed rails, tailgate weatherstripping, and any area you don't want coated. Use automotive masking tape — standard painter's tape won't hold the overspray.
6. Apply the first coat with a roller in long, even strokes. Brush into corners and wheel well curves where the roller can't reach. Coverage should be even — avoid thick puddles.
7. Let the first coat flash for 2–4 hours (per product instructions) before applying the second coat. Two coats are minimum; three coats in high-wear areas (tailgate, behind the wheel wells) is better.
8. Remove masking tape while the final coat is still slightly tacky. Pulling tape after full cure can lift the liner edge.
9. Allow 48–72 hours full cure before loading heavy gear. The liner will off-gas during cure — don't park in an enclosed garage during this period.
Professional spray-in (Line-X, Rhino Linings): $450–600. Longest-lasting option with a transferable warranty at most franchise shops.
Herculiner DIY kit (1 gallon, covers a full JT bed): ~$65–75. Adequate for light-duty protection, but prep work determines the outcome.
Durabak 18 (1 gallon): ~$85–95. Thicker formulation than Herculiner, better suited for a truck that hauls trail gear.
BedRug Custom Mat for JT: ~$240–260. Removable, carpet-like surface with good drainage — the overland-friendly alternative to a permanent coating.
| Part | Vendor | Est. price |
|---|---|---|
| Durabak 18 Truck Bed Liner — 1 Gallon Roll-On | Durabak | ~$89 |
| Herculiner HCL0B8 Bed Liner Kit | Herculiner | ~$69 |
| Rough Country RCRB100 Hard Tri-Fold Tonneau Cover | Rough Country | ~$499 |
| BedRug IMJ20SBS Bed Mat for JT | BedRug | ~$249 |
Written and maintained by an AZ wheeler and driveway wrencher. Always cross-reference your factory service manual — modifications affect vehicle safety and warranty. Work at your own risk.