2026 Grand Design Momentum M-Class 399M
- Year 2026
- Make Grand Design
- Model Momentum M-Class
2026 Grand Design Momentum M-Class 399M
2026 Grand Design Momentum M-Class 399M
Our top-of-the-line Momentum Fifth Wheel Toy Haulers are — inside and out — our most luxurious Toy Haulers. With the comfort of a master suite and master bath, home’s now a long way from your house.
Features may include:
- Thermal Roof Design (R-40)*
- Fully Laminated Walls (R-11)*
- Triple Insulated Main Floor (R-45)*
- Triple Insulated Garage Floor (R-40)*
- 1.5" Insulated Baggage Doors
- Vented Attic
- Insulated Gooseneck
- Rail-Tite Underbelly Seal
Dimensions
Overall Height
13' 6" | (w/opt. AC): 13' 6"
Overall Length
44' 10"
Overall Width
8' 5"
Interior Height
8' 5"
Dimensions
Standard Bed: 60 X 80 Queen Bed | Standard Bunk: 30 X 80 | Shower: 48 X 30
Garage Length
12' 6"
Awning Size
14' 9' 12'
Weights
Hitch Weight Capacity
3,464 lbs.
Unloaded Weight
18,000 lbs.
GVWR
22,500 lbs.
Capacities
Fresh Water Capacity
140 gal.
Gray Water Capacity
104 gal.
Black Water Capacity
52 gal.
LP Tank Capacity
60 gal
Sleeping Capacity
9
Fuel Capacity
60 lbs
Water Heater
On-Demand
Refrigerator
20 cu. ft.
Features
Features
Propane Tanks: 2 | Construction Type: Aluminum Cage | Slide Room R-Value: R-11 | Garage R-Value: R-40 | Slides: 3 | Awnings: 3
R-Value, Floor
R-45
R-Value, Wall
R-11
R-Value, Roof
R-40
Operational
Furnace Output
35,000 BTU
Air Conditioner Output
30,000 BTU
Chassis
Axle Count
3
Wheels & Tires
Wheels
17.50 in.
Tires, Rear Specification
ST215/75R17.5 LRH