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2026 Grand Design Momentum 399M
NewStock #P160042
Listing price
2026 Momentum 399M
Other floor plans with a similar body style, feature mix, and price range, prioritizing other manufacturers and brands.
The Grand Design Momentum 399M puts its toy-hauler garage at the center of the adventure, with a rear ramp setup and optional aluminum deck system that expands the outdoor living space. Inside, a fireplace with electric heat, LED smart TV, Rockford Fosgate entertainment system, and matte black 20 cu. ft. refrigerator make the living area feel polished and comfortable. A one-piece fiberglass shower with glass door and teak bench, porcelain toilet, and dedicated bedroom storage round out the full-bath layout, while MORryde independent suspension, disc brakes, and a six-point hydraulic leveling system support confident setup and handling.
Length
44 ft 10 in
Dry weight
19,170 lbs
GVWR
23,500 lbs
Sleeps
4
Many factors play into a unit's listing price and what you should pay. This guide provides a ballpark estimate, but it does not factor in your exact scenario or how different listings are equipped.
There may be room for price negotiation.
$121,995 – $156,995
This unit has been on the lot for 31 to 60 days.
This unit is ranked 7 of 23 by asking price in this group.
The listing price on this unit has changed 1 time.
See the complete price timeline and the rest of this unit's pricing insights.
Meyer's RV
Branchville, NJ
Sells faster than 54% of US RV dealers
Compared with 1,118 dealers nationwide
Grand Design Momentum fifth wheel toy hauler 399M highlights:
MORRYDE 7K INDEPENDENT SUSPENSION 2.0 W/DIC BRAKES
Front Private Bedroom
Kitchen Island
Hybrid Desk/Dinette
Unobstructed Pass-Thru Storage
Side Patio
This toy hauler has all the comfort and convenience you could ask for! Once you have unloaded your toys from the 12' 6" separate garage, you can start lunch on the exterior griddle located by the side patio. There is also a 65" TV here and a 1.7 cu. ft. refrigerator to entertain guests! And if you have guests staying over, you can choose to add the optional Liftsuite system with underside can lights in the garage. If the weather isn't cooperating, you can make meals in the fully equipped interior kitchen, complete with an island, pantry, pull-out countertop extension and more. An L-shaped sofa with recliners is in perfect view of the 50" TV and fireplace, and there is even a hybrid desk/dinette with windows where you can get some work done if needed. Head towards the front to freshen up in the full bath before heading to bed in the private bedroom. Here, you'll find a queen bed slide out with an optional king bed, a large closet with washer and dryer prep, plus a dresser with TV prep if you want the option to watch movies in bed!
The Momentum fifth wheel toy haulers by Grand Design are built for four seasons of travel with your off-road toys and include luxurious accommodations throughout for extreme living! Each is constructed to a superior standard with the fully enclosed and heated underbelly and storage area, the 5-sided aluminum cage, and the triple insulated garage floor. The MORryde independent suspension 2.0 and rubber pin box, plus the upgraded axle hangers provide the performance and smooth towing you desire, while the interior offers luxury such as color changing LED accent lighting, hardwood cabinet doors with hidden hinges, and a central vacuum system. Each toy hauler also includes four packages, including the Garage Package with Tuff-Ply gas and oil-resistant flooring, the Weather-Tek Package with a Stealth AC System, and the Interior Luxury Package with solid surface countertops!
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