2026 FOREST RIVER SIERRA 3990FL

The 2026 Forest River Sierra 3990FL is a luxury front-living (FL) fifth wheel that masterfully hides a massive amount of sleeping space within a sophisticated, residential-style layout. It is best known for its "hidden" loft and five-slide-out configuration.

Core Specifications

• Exterior Length: 43' 6"

• Dry Weight (UVW): ~12,439 lbs

• Hitch Weight: ~2,825 lbs

• Slides: 5 (Dual living room, dual kitchen, single bedroom)

• Sleeping Capacity: Up to 8 people

Key Living Features

• Elevated Front Living Room: A dedicated entertaining space featuring two tri-fold hide-a-bed sofas, theater seating, an electric fireplace, and a 50" pop-up Smart TV that disappears when not in use.

• The "Secret" Loft: Located above the rear master bedroom and bathroom, this loft features two 44" x 74" bunk mats, wardrobes, and storage, making it perfect for kids while keeping the main floor clear.

• Center Island Kitchen: A chef’s layout with a large stainless sink in the island, a 16 cu. ft. 12V refrigerator, and a Chef Collection 24" oven with a three-burner cooktop.

• Master Suite: Features a King Bed slide, a walk-in closet prepped for a washer/dryer, and easy access to a bathroom with a residential one-piece fiberglass shower with a seat.

Premium Build & Tech

• All-Weather Construction: Built with vacuum-bonded laminated sidewalls and Underbelly Armor, protecting the 12V heated holding tanks and mechanicals from road debris and cold.

• Solar & Power: Comes standard with a 200W roof-mounted solar panel and a 30-amp controller, supported by 50-amp service and a 65-amp converter.

• High-End Comfort: Includes a 60,000 BTU on-demand tankless water heater for endless hot showers and dual 15,000 BTU ducted A/C units (with prep for a third).

• Towing Stability: Rides on 7,000 lb axles with Anti-lock Braking Systems (ABS) and Goodyear Radial tires for a safer, smoother tow.