2026 Grand Design Momentum 399M

New Toy Hauler in Corinth, Texas, 76210

$156,996.00

Show All 72 Photos

New 2026 Grand Design Momentum 399M available in Corinth, Texas

2026 Grand Design Momentum 399M - New Toy Hauler For Sale by McClain's RV Superstore in Corinth, Texas features Kitchen Sink, Ramp, Fire Extinguisher, TV, King Size Bed

2026 Momentum 399M by Grand Design from McClain's RV Superstore in Corinth, Texas

Unit Specs

Stock #15732
Year2026
ManufacturerGrand Design RV
Make Grand Design
ModelMomentum
Floorplan399M
Floorplan LayoutFront Bedroom
Mid Kitchen
Mid Living Area
Two Entry/Exit Doors
Type Toy Hauler
Secondary Type Fifth Wheel
ConditionNew
Length44' 10"
Width8' 5"
Height13' 6"
VIN573FM473XTBB04988
MSRP $196,512.00
Sale Price $156,996.00
Need to know your payment? Use our RV Loan Calculator!
Chassis101" Wide Body Super Chassis w/Drop-Frame Storage
Sleeps6
Water Capacity (Fresh)140 gal
Water Capacity (Black)52 gal
Water Capacity (Grey)104 gal
Air Conditioners3
A/C Spec3 X 15K BTU
Refrigerator Capacity20 ft³
Slideouts3
Payload Capacity4500 lbs
Dry Weight18,000 lbs
Tow/Hitch Weight3464 lbs
# Axles3

Looking to buy a 2026 Grand Design Momentum Toy Hauler RV?

Spacious rear garage toy hauler — room for quads, bikes, side-by-sides, or gear
Side patio with outside kitchen and entertainment
Two large slide-outs open the living/kitchen area wide
Front bedroom with privacy and solid storage
Full galley kitchen with island, big fridge, and real prep space
Comfortable living area with theater seating and sofa
Large bathroom with separate shower and good circulation
Excellent tank capacities and utility setup for longer trips
Built solid with Grand Design’s everyday-use quality
Power awning with LED lighting and ample exterior storage

If you want a toy hauler that doesn’t feel like a toy hauler — meaning it lives comfortably inside whether you’re hauling toys or not — the 2026 Grand Design Momentum 399M delivers exactly that. The rear garage is spacious enough for quads, bikes, or gear with real tie-downs and a proper ramp, but once you’re parked and set up, the interior feels like a real home on wheels.

The dual slide-outs make a huge difference — with them out, the kitchen and living area feel wide, open, and easy to walk around in instead of cramped. The kitchen itself is laid out thoughtfully with an island that gives you serious prep space, a big fridge, and storage that actually works. You’re not juggling pots and pans in every nook and cranny — you’ve got room to cook.

The living area has comfortable seating — theater seats and a sofa you’ll actually use — with a good entertainment setup, so relaxing after a long day doesn’t feel like an afterthought. Up front, the private bedroom gives you a real bed and plenty of storage, and the bathroom’s layout is practical with a good-sized shower and useful circulation.

Tank capacities and utility hookups are sized for extended stays — no stressing about hookups after a night or two. Outside, the power awning with LED lighting makes the campsite area feel like an extension of the interior, and the exterior storage bays are deep enough for chairs, tools, grills, and whatever gear you bring along.

Bottom line: the Momentum 399M is comfortable, practical, and built for real adventure — whether you’re hauling toys or just want a big, well-laid-out rig for camping, road trips, or extended travel. Easy to live in, easy to enjoy — exactly what you want out of a modern toy hauler.

View a video of this 2026 Grand Design Momentum 399M RV on YouTube!

2026 Grand Design Momentum 399M Features

Appliances
Furnace, Microwave, Refrigerator, Stove Top Burner, Water Heater
Electrical
Air Conditioning, Batteries, Solar Prep
Equipment
CO Detector, Fire Extinguisher, LED Lights, LP Detector, Propane, Smoke Detector, TV, TV Antenna
Exterior
Awning, Black Tank Flush, Detachable Power Cord, Enclosed Underbelly, Exterior Speakers, Heated Underbelly, Leveling Jacks, Pass Thru Storage, Ramp, Roof Vent, Screen Door, Slideout, Tinted Windows
Interior/Furnishings
Central Vacuum, Day/Night Shades, Fireplace, Free Standing Dinette w/Chairs, Island Kitchen, King Size Bed, Kitchen Sink, Medicine Cabinet, Overhead Cabinetry, Pantry, Roof Vents, Shower, Table and Chairs, Theater Seating, Toilet, Wardrobe(s)