New 2026 Grand Design Momentum M-Class 399M
- SALE PRICE: $149,995
- MSRP: $195,561
- You Save: $45,566
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45ft long
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19,170 lbs
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Sleeps 4
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3 slides
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Kitchen IslandTwo Entry/Exit Doors
399M Floorplan
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 | 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 | 573FM4733TBB04718 |
Description
New 2026 Grand Design Momentum M-Class 399M
The New 2026 Grand Design Momentum M-Class 399M is built for RVers who want top-tier luxury combined with serious toy hauling capability. Featuring a spacious 13-foot garage, this floorplan is perfect for bringing along motorcycles, ATVs, or side-by-sides while still offering a high-end residential interior. The garage easily converts into a flexible living and sleeping space with rollover sofas, a HappiJac bed system, and a loft above, giving you plenty of room for guests or family.
The main living area offers a wide-open layout with multiple slide-outs, creating a true residential feel with theater seating, a large sofa, and an entertainment center for relaxing after a day of adventure. The kitchen is designed for real cooking on the road, featuring a large kitchen island, residential refrigerator, cooktop, oven, microwave, and abundant cabinetry, while the bath and a half layout adds extra convenience, especially for guests using the garage area.
Toward the front, the private master suite provides a comfortable king bed, wardrobe storage, and dresser space, creating a quiet retreat at the end of the day. The main bathroom includes a spacious residential-style shower and vanity, while outside, dual power awnings and large exterior storage compartments create the perfect outdoor setup for relaxing and entertaining. With its versatile garage, luxury features, and Grand Design craftsmanship, the Momentum M-Class 399M is built for both adventure and comfort.
Key Features & Highlights
• 13' toy hauler garage for motorcycles, ATVs, or gear
• HappiJac bed lift system with convertible seating
• Loft sleeping area for additional guests
• Bath and a half for added convenience
• Spacious living area with theater seating and sofa
• Kitchen island for meal preparation and serving
• Residential refrigerator, cooktop, oven, and microwave
• Private front bedroom with king bed
• Large bathroom with residential-style shower
• Dual power awnings for outdoor living
• Exterior storage compartments for camping gear
Why Choose Campers Inn RV
When you choose Campers Inn RV, you’re partnering with a team dedicated to helping you enjoy the RV lifestyle with confidence. Our RV Match Makers work closely with you to find the perfect RV for your travel goals, lifestyle, and budget. Every new RV we offer is carefully inspected and prepared by certified technicians so it’s ready for adventure. With flexible financing options, transparent pricing, and dependable service support whenever you need it, Campers Inn RV of Knoxville makes RV ownership simple and exciting.
See It In Person Today
Experience the luxury, space, and adventure-ready design of the Grand Design Momentum M-Class 399M for yourself. Call or text 865-933-7213 today to schedule your walkthrough or learn more from the team at Campers Inn RV of Knoxville.
- Luxury Interior Package
- Exterior Package
- Weather-tek Insulation Package
- Under Unit LED Light Kit
- Bedroom A/C
- 20 Cu. Ft. 12V Refrigerator
- OmniConnect
- Upgraded H-rated Tires w/ 17.5” Wheels
- SafeRide RV Roadside Assistance
- RVIA Seal
- 6K Watt Generator
- Gen III 3 Season Door w/ Sliding Windows
- 3rd A/C Prep
- Rockford Fosgate Stage 1 Stereo
- Momentum Garage Suite w/ p2k Bed lift
- Solar + Package
- Kitchen Power fan w/ Rain Sensor
- Garage LED HD TV
- Auxiliary Fresh Water Tank
- King Bed Upgrade
- 3rd A/C
- Heat Pump A/C
- Momentum Patio Chairs
- Rear Aluminum Deck System w/Rear Power Awning
- MorRyde 7K Independent Suspension 2.0 w/ Disc Brakes – Triple Axle
Features
Standard Features
Exterior
- Keyed Alike™ Ramp Door Latches
- 2nd Patio Awning w/ LED Lights
- 3rd Awning w/LED Lights (Main Slide-395MS)
- Exterior Color Changing LED Accent Lighting
- High-Gloss Gel Coat Exterior Sidewalls
- Door Side Exterior Spray Port
- Frameless Tinted Windows
- Walk-On Roof
- 17.5" Spare Tire (Undermount)
- MORryde Strut Assist Entry Step
- Slam-Latch Baggage Doors
- Mo Secure
Construction
- 101" Wide-Body Construction
- 5-Side Aluminum Cage Construction
- Fully Enclosed Underbelly w/Heated Tanks and Storage
Running Gear
- Upgraded Axle Hangers
- Heavy Duty H-Rated Tires
- Heavy Duty 7,000lb. Axles with ABS Drum Brakes (381MS, 395MS)
- Heavy Duty 8,000lbs. Axles with ABS Drum Brakes (351MS)
- 17.5" H-Rated Aluminum Wheels
- MORryde® CRE3000 Suspension System
- Tow Assist ABS & Sway Mitigation System
Frame & Chassis
- 6-Point Hydraulic Leveling System
- 101" Wide Body Super Chassis
Interior
- Interior Color Changing LED Accent Lighting
- Hardwood Cabinet Doors w/Hidden Hinges
- Recliner Sofa w/Adjustable Headrest or Flip Down Cupholders
- Central Vacuum System w/ Tools and Dust Pan
- Plywood Drawer Bottoms
Kitchen
- Microwave
- Residential Kitchen Faucet
- Professional Grade Stainless Steel Cooktop
- 12v High Power MaxxAir Fan with Rain Sensor
- Window Behind Range (N/A 395MS)
- Kitchen Barstools w/Extended Countertops (351MS, 381MS)
- Smart Sink w/removable cutting board, produce strainer and glass rinser
Electrical
- Solar Prep (10 gauge wiring with universal MC4 connectors)
- 75 Amp Converter
- 12V Battery Disconnect
HVAC
- 12v High Power Fan (Kitchen)
- 35K BTU High Capacity Furnace
- Stealth AC System w/ Insulated A/C Ducts
- Attic Vent
- High Capacity Heat Ducts
Plumbing
- Exterior Spray Port (Door Side)
- 12V Tank Heaters
- Sewer House Storage Area
- Whole House Water Filtration System
- All-In-One Enclosed Utility Center
Bedroom
- Under Bed Storage Area
- Individually Switched Reading Lights Over Bed
- Bedside 110-Volt & USB Outlets
- Window Above Master Bed Headboard
- 60" x 80" Queen Pillow Top Bed Mattress
Bathroom
- Porcelain Toilet
- Medicine Cabinet w/Mirrored Door
- Undermount Lav Sink
- One-Piece Fiberglass Shower w/Glass Door & Teak Bench Seat
Appliance
- Fireplace with Electric Heater
- Stainless Steel 20 cu. ft. Refrigerator
- 30" Over-The-Range Microwave
Electronics
- Exterior Cable/SAT Plug-In
- LED Smart TV in Living Area
- Rockford Fosgate Stereo Ent. System w/HDMI and App Controls
- Exterior Speakers
- No-Crank Digital TV Antenna w/Booster
- LED TV in Garage (NA 336M)
- TravLFi On-Board WiFi Ready
Packages
Exterior Package
- Satellite TV Prep
- MORryde Strut Assist Entry Step
- Aluminum Quad Entry Steps - Garage Entry
- 7,000 lb. Axles w/Self Adjusting Brakes, Wet Bolts and Bronze Bushings
- 17” Aluminum Wheels (120PSI Rated)
- Cooper Tires® 17.5" All-Steel H-Rated Tires
- Slam-Latch Baggage Doors
- Frameless Tinted Windows
- Exterior Security Lights
- Power Patio Awning w/LED Lighting
- Folding Roof Ladder
- White Gel Coat Fiberglass Front Cap
- 12V Battery Disconnect
- All-In-One Exterior Utility Center
- 50 Amp Service
- Converter
- Enclosed Fuel Station w/ Dual Fuel Tank (Single Tank 336M)
- Partial Paint Gel Coat Fiberglass Front Cap
Interior Package
- 49" Class LED TV in Living Area
- Stereo Entertainment System w/Bluetooth and App Based Controls in Living Area
- Washer/Dryer Prep
- On Demand Water Heater
- Roller Shade Window Coverings (Main Living Area and Bedroom)
- Recessed LED Puck Lighting
- Solid Surface Countertops w/ Sink Covers
- Stainless Steel Undermount Kitchen Sink
- Chef Inspired Range & Oven w/ Cover
- Kitchen Pantry w/ LED Light Strip
- Garage Control Panel
Garage Package
- 32" Class LED TV in Garage
- Protective Diamond Plate on Garage Sidewalls
- 2,500 lb. Rated Flush-Mount Tie-Downs
- Ram-Air Garage Vents Both Sides
- Tuff-Ply Gas and Oil Resistant Garage Flooring
- FastRamp Rear Ramp Door
- Triple Insulated Garage Floor
Weather-Tek Package
- R-Value Equivalent (R-40 Roof / R-45 Floor / R-11 Sidewalls / R-40 Garage Floor / R-24 Slideroom Floor)
- Fully Enclosed and Heated, Underbelly and Storage Area
- Enclosed and Heated Low Point Drains
- Engineered Underbelly Airflow Heat Paths
- Stealth AC System w/ Insulated A/C Ducts
- Attic Vent
- Plumbing Line Insulation Barrier
See us for a complete list of features and available options!
All standard features and specifications are subject to change.
All warranty info is typically reserved for new units and is subject to specific terms and conditions. See us for more details.
Due to the current environment, our features and options are subject to change due to material availability.
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*All calculated monthly payments are an estimate for qualified buyers only and do not constitute a commitment that financing or a specific interest rate or term is available. Financing terms may not be available in all Campers Inn locations. Campers Inn RV Sales is not responsible for any misprints, typos, or errors found in our website pages. Any price listed excludes sales tax, registration tags, and delivery fees. Manufacturer pictures, specifications, and features may be used in place of actual inventory in stock on our lot. Please contact us for availability as our inventory changes rapidly.
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.
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.



