New 2026 Grand Design Momentum 399M Toy Hauler Fifth Wheel

Generator Go RVing
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! 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 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!

 

 

Options:
  • 20 CU FT 12V REFRIGERATOR (+ INVERTER PREP
  • 330W SOLAR PANEL
  • 50 AMP CONTROLLER
  • BLUETOOTH MODULE AND 2 DOCK PORTS)
  • 3RD A/C
  • 3RD A/C PREP
  • 6K WATT GENERATOR
  • AUXILIARY FRESH WATER TANK
  • BEDROOM A/C
  • EXTERIOR PKG
  • GARAGE LED HD TV
  • GARAGE PKG
  • GEN III 3 SEASON DOOR WITH SLIDING WINDOWS
  • HEAT PUMP A/C
  • KING BED UPGRADE
  • KITCHEN POWER FAN W/RAIN SENSOR
  • LUXURY INTERIOR PKG
  • MOMENTUM GARAGE SUITE FEATURING P2K BED LIFT
  • MOMENTUM PATIO CHAIRS
  • MOR RYDE 7K INDEPENDENT SUSPENSION 2.0 W/DISC BRAKES - TRIPLE AXLE
  • OMNICONNECT - SATELLITE
  • CELLULAR AND WIFI INTERNET PREP
  • REAR ALUMINUM DECK SYSTEM W/REAR POWER AWNING
  • ROCKFORD FOSGATE STAGE 1 STEREO - 500 WATTS
  • INT/EXT SPEAKERS W/10" POWERED SUB
  • RVIA SEAL
  • SAFERIDE RF ROADSIDE ASSISTANCE
  • SOLAR + PKG (ONE ADDITIONAL 330W PANEL & 2000W INVERTER)
  • UNDER UNIT LED LIGHT KIT
  • UPGRADED H-RATED TIRES W/17.5" WHEELS (TRIPLE AXLE)
  • WEATHER-TEK INSULATION PKG
What Our Customers Are Saying

Referred me to great service!

Although they couldn’t help with the repair of my specific problem, they were willing to take the time to help me locate another dealer/repair shop in town who could. - Joseph
Price: $198,078
Crestview RV
Location: South Austin - Buda
Stock# 32427
To get help now on this RV, call and enter the RV ID if prompted.
RV ID: 3191547#
(enter this ID if prompted)
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
Exterior Color 22500
Hitch Weight 3406 lbs
GVWR 23500 lbs
Dry Weight 19170 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 573FM473XTBB04652
For more information Contact Us

Momentum 399M Reviews

Be the first to tell other RVers what you think about this RV  Write a Review
Similar RVs and Floorplans

Loading

.

Manufacturer and/or stock photographs may be used and may not be representative of the particular unit being viewed. Where an image has a stock image indicator, please confirm specific unit details with your dealer representative.