2026 Grand Design Momentum 399M
Toy Hauler · Fifth Wheel Toy Hauler · 44.83 ft · sleeps 5
The 2026 Grand Design Momentum 399M is a toy hauler (fifth wheel toy hauler) built on a Momentum full-frame. At sleeps 5, 44.83 ft long, 19,170 lbs dry, it's positioned for owners who haul motorcycles, ATVs, or bikes.
Floor plan
Photos of the 2026 Grand Design Momentum 399M
Walkthrough video
Video courtesy of McClain's RV on YouTube.
Full specifications
Dimensions
| Length | 44.83 ft |
|---|---|
| Slide-Outs | 3 |
Weights
| Dry Weight | 19,170 lbs |
|---|---|
| GVWR | 23,500 lbs |
Living
| Sleeps | 5 |
|---|---|
| Bunkhouse | No |
Tanks
| Fresh Water | 140 gal |
|---|---|
| Grey Water | 104 gal |
| Black Water | 52 gal |
Amenities
| Outdoor Kitchen | No |
|---|---|
| Theater Seating | No |
| Residential Fridge | No |
| Fireplace | No |
| Four-Season | No |
| Off-Road Capable | No |
Similar Toy Haulers to consider
Other toy haulers in the catalog with comparable size and price.
Frequently asked questions
How many people does the 2026 Grand Design Momentum 399M sleep?
The 2026 Grand Design Momentum 399M sleeps 5.
How long is the 2026 Grand Design Momentum 399M?
The 2026 Grand Design Momentum 399M is 44.83 feet long.
What's the dry weight of the 2026 Grand Design Momentum 399M?
The 2026 Grand Design Momentum 399M has a dry weight of 19,170 lbs and a GVWR of 23,500 lbs.
Where can I buy the 2026 Grand Design Momentum 399M?
Pirka Wakka is a brand-agnostic catalog and doesn't sell RVs. The "Buy on Grand Design" link on this page sends you to the manufacturer's product page — they'll route you to an authorized dealer.
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