New 2026 Grand Design Momentum M-Class 399M Toy Hauler Fifth Wheel
Rainy day? No problem. The interior kitchen is a culinary playground, featuring a kitchen island, pull-out countertop extension, deep storage, pantry, and upscale appliances.
NEW 2026 Grand Design Momentum 399M Toy Hauler — Elevate Every Adventure
If you’ve been searching for a fifth wheel toy hauler that checks every box—power, luxury, workspace, entertainment, and real off-grid capability—the Momentum 399M was built for you. Grand Design’s flagship toy hauler welcomes thrill-seekers and full-timers alike with refined residential comforts and rugged durability that can keep up with wherever your journey leads.
Load Up, Level Up, and Live Large
The 12' 6" separate garage gives you the freedom to bring quads, dirt bikes, kayaks, e-bikes—anything that fuels your weekends. Once unloaded, transform the space into an extra suite with the optional Liftsuite system, complete with under-glow accent lights for a premium touch. And when you want to take the party outside, the side patio becomes your open-air living room—outfitted with a 65" TV, a 1.7 cu. ft. fridge, and an exterior griddle to keep everyone fed and smiling.
A True Chef's Kitchen… Indoors or Outdoors
Rainy day? No problem. The interior kitchen is a culinary playground, featuring a kitchen island, pull-out countertop extension, deep storage, pantry, and upscale appliances. Whether you’re prepping trail-day snacks or hosting friends for dinner, you’ll have the space and style to do it right.
Relaxation Worth Coming Home To
Kick back in the main living area where an L-shaped reclining sofa faces a 50" TV and ambient fireplace—the perfect setup after a long day on the trails. Need to squeeze in some work? The innovative hybrid desk/dinette with panoramic windows gives you a scenic remote-work station without sacrificing dining space.
Your Private Bedroom Retreat
At the front of the coach, unwind in the spacious master suite with a queen bed slide (optional king!), a large wardrobe with washer/dryer prep, and a dresser with TV prep. Whether you’re weekend camping or living full-time, this bedroom delivers the storage, comfort, and separation you need.
Built for All Seasons & All Terrains
Every Momentum is engineered for durability and all-weather performance with a fully enclosed/heated underbelly, 5-sided aluminum cage, and triple-insulated garage floor. Ride smoother with the MORryde CRE3000 suspension, rubber pin box, and upgraded axle hangers. Inside, enjoy upscale touches like hardwood cabinet doors, hidden hinges, solid surface countertops, color-changing LED lighting, and even a central vacuum system. Four premium packages—including the Garage Package, Weather-Tek Package, and Interior Luxury Package—ensure you don’t just arrive… you arrive in style.
Your Toys Deserve a Better Home. So Do You.
If you’ve dreamed of a toy hauler that works hard, plays harder, and pampers you at the end of every drive, the 2026 Momentum 399M is the one you’ll want to see first—and last.
Make it yours today at Little Dealer Little Prices—where your next adventure begins at a price you’ll feel great about.
INVENTORY IMAGES MAY BE SHOWN. COLORS AND SPECS MAY VARY. CALL FOR DETAILS.
Randy was awesome to deal with! Everything went smoothly and the prices were descent! Randy was good about keeping in touch with repairs and helpful! Loving our camper! - RaeLynn
Stock# 21173437
Interior Color: ARTISAN
| Sleeps | 4 |
| Slides | 3 |
| Length | 44 ft 10 in |
| Ext Width | 8 ft 5 in |
| Ext Height | 13 ft 6 in |
| Int Height | 8 ft 5 in |
| Interior Color | ARTISAN |
| Hitch Weight | 3464 lbs |
| GVWR | 22500 lbs |
| Dry Weight | 18000 lbs |
| Fresh Water Capacity | 140 gals |
| Grey Water Capacity | 104 gals |
| Black Water Capacity | 52 gals |
| Tire Size | 17.5" |
| Furnace BTU | 35000 btu |
| Fuel Capacity | 60 gals |
| Available Beds | Queen |
| Refrigerator Type | 12V Stainless Steel |
| Refrigerator Size | 20 cu ft |
| Cooktop Burners | 3 |
| Number of Awnings | 3 |
| Axle Weight | 7000 lbs |
| Garage Size | 12 ft 6 in |
| LP Tank Capacity | 30 lbs |
| Water Heater Type | On Demand |
| AC BTU | 30000 btu |
| TV Info | LR 50" LED TV, Garage 32" LED TV, Patio 65" TV |
| Awning Info | 9', 12', 14' Power w/LED Lights |
| Axle Count | 3 |
| Washer/Dryer Available | Yes |
| Number of LP Tanks | 2 |
| Shower Type | Shower w/Seat |
| Electrical Service | 50 amp |
| VIN | 573FM4736TBB04387 |
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