New 2026 Forest River RV Sierra 3990FL

Forest River Sierra fifth wheel 3990FL highlights:

The perfect fifth wheel for a larger family! This unit sleeps eight or more with the full and half lofts above the rear master bedroom and bathroom. In the full loft area there are two 44" x 74" bunk mats for comfort as well as wardrobe/storage at the head of each. The master bedroom features a king size bed that slides out to create more space by the bed. A spacious bath features a walk-in shower for comfort and includes a seat so you can relax while you shower. A spacious kitchen features two slides, a free standing dinette in one, and the 12V refrigerator and stove in the other. There is also a center island with large sink for added food prep space. Head up the steps in front to a dual slide front living area with 50" TV and fireplace beneath the window. There is also theater seating opposite the TV, and a tri-fold hide-a-bed in each slide allowing added sleeping space when needed.

Each one of these Forest River Sierra fifth wheels are equipped with everything you need to make the most of each adventure! The underbelly armor will protect your unit's vitals from road debris and the painted two tone aerodynamic fiberglass front cap has an improved turning radius to make them easier to navigate. With an electric leveling system, you can set your unit up quick and easy then get to having fun faster than ever. The welded aluminum framed, vacuum bonded laminated superstructure will hold up through every adventure and the cambered powder coated frame comes with rust prohibitor to last longer. Each model also includes the Summit Package that comes with a king Wi-Fi extender system and Olympus antenna, a full coach water filter system, Goodyear tires with 7,000 lb. axles, and the list goes on. The interior is just as impressive with rustic wood plank linoleum, recessed residential lighting, a memory foam mattress, and mocha accent crown molding over the kitchen cabinets!

Standard Features (2026)

Exterior Features

Interior Features

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Construction

For Your Safety

Popular Options

Please see us for a complete list of features and available options!

All standard features and specifications are subject to change.

All warranty info is typically reserved for new units and is subject to specific terms and conditions. See us for more details.

Due to the current environment, our features and options are subject to change due to material availability.