New 2026 Grand Design Momentum 399M Toy Hauler Fifth Wheel

2026 399M Features and Options
Grand Design Momentum fifth wheel toy hauler 399M highlights:
  • 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!  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 king bed slide out, 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 CRE3000 suspension system 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!

 

 

What Our Customers Are Saying

Fantastic service and support!

Fantastic service and support. Jim and Mike know RVs and even more important know the industry and all the conditions that are affecting RV sales. In addition, RV Kountry went above any beyond when it comes to the sale of my coach. They coordinated battery replacements and other repairs. I would highly recommend RV Kountry. Thanks for all your help. - Greg
Price: $186,840
You Save: $21,845
Sale Price: $164,995
General RV- SUSPENDED PER BILLING
Location: Philadelphia, PA
Stock# 340943


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
Hitch Weight 3464 lbs
GVWR 22500 lbs
Dry Weight 18176 lbs
Fresh Water Capacity 140 gals
Grey Water Capacity 104 gals
Black Water Capacity 52 gals
Tire Size 17.5"
Furnace BTU 35000 btu
Generator NPS 6000
Fuel Capacity 60 gals
Available Beds King
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 573FM4732TBB04614
For more information Contact Us
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