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.
Fireplace Toy Hauler
2026 399M Features and Options

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.

What Our Customers Are Saying

Loving our camper!

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
Price: $181,832
Campers Inn
Location: Mesa, AZ
Stock# 21173437
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RV ID: 3368799#
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2026 399M Specifications
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
For more information Contact Us
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