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New 2025 Grand Design Momentum M-Class 398M

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Call Today 661-247-4549
2025 398M Features and Options

Grand Design Momentum M-Class toy hauler 398M highlights:

  • 18' Separate Garage
  • Bedroom Wardrobe Slide
  • Four-Seat Super Sofa
  • Kitchen Island with Bar Stools
  • Dual Entry Doors
  • Flip Up Pet Dish

 

Load up your toys, gear, clothes and food to enjoy some off-road fun with your toys and friends! Once at the RV park, unload your toys and set up the three slide outs and two awnings, and begin planning your trail rides! You might decide to make a meal or snack in the combined kitchen and main living area which offers all the appliances you need, plus a kitchen island with two bar stools, a pantry, an LED TV with a fireplace below, plus a slide out four-seat sofa. The garage even offers sofas and an overhead bed plus the option to add two additional Happi-Jac rollover sofas with tables with a top bed if you want seating and sleeping space. The overhead loft bed provides sleeping space as well. You will love the shower with a seat in the full bathroom with a space saving sliding door, and the front bedroom can be your escape. There is a queen bed, a slide out wardrobe and USB charging outlets.

 

With any Momentum M-Class toy hauler by Grand Design, you will enjoy luxury at every turn! They have been constructed to a superior standard with a thermal roof design, triple insulated main floor and garage floor, and a Rail-Tite underbelly seal that will allow you to camp in all elements. Each model also features an 8' 5" wide body chassis with a wide rail design, no wheel wheels, and a dovetail entry for easier loading. The Stealth A/C system provides maximum cooling power, and the CRE3000 suspension system means you can enjoy a smooth tow each time. You will love the luxurious interior with a professional grade stainless steel cooktop, interior color changing LED accent lighting, a fiberglass shower with a glass door, and solid surface countertops. 

 

Options:
  • 20 CU FT 12V REFRIGERATOR
  • 3RD A/C
  • 3RD A/C PREP
  • 7K AXLE W/ABS DRUM BRAKES
  • AUXILLARY FRESH WATER TANK
  • BEDROOM A/C
  • EXTERIOR ENTERTAINMENT CENTER
  • EXTERIOR PKG
  • GARAGE LED HD TV
  • GARAGE PKG
  • GEN II 3 SEASON DOOR
  • HAPPI-JAC ELECTRIC BUNK
  • HEAT PUMP A/C
  • KITCHEN POWER FAN W/ RAIN S
  • LUXURY INTERIOR PKG
  • MOMENTUM PATIO CHAIRS
  • REAR ALUMINUM DECK SYSTEM
  • ROCKFORD FOSGATE STG 1
  • RVIA SEAL
  • SAFERIDE RV ROADSITE
  • SOLAR ½ PKG
  • TRAVLFI ON-BOARD WIFI
  • UNDER UNIT LED LIGHT KIT
  • UPGRADED COOPER H RATED TIRES
  • WEATHER-TEK INSULATION PKG
  • YAMAHA GENERATOR
What Our Customers Are Saying

Very helpful

"The sales associate and the Finance Mgr involved with our transaction were very pleasant and answered all of our questions. We would not have been able to complete our transaction without their help. Appreciatively, Scott & Sandra Follansbee" - Scott
MSRP: $160,050
Location: Bakersfield
Stock# 69942
2025 398M Specifications
Sleeps 8
Slides 3
Length 43 ft 10 in
Ext Width 8 ft 5 in
Ext Height 13 ft 5 in
Int Height 8 ft 5 in
Interior Color MAGNOLIA
Hitch Weight 2980 lbs
GVWR 20000 lbs
Dry Weight 15000 lbs
Fresh Water Capacity 140 gals
Grey Water Capacity 52 gals
Black Water Capacity 52 gals
Tire Size ST215/75R17.5 LRH
Furnace BTU 35000 btu
Fuel Capacity 60 gals
Number Of Bunks 1
Available Beds Queen
Refrigerator Type Stainless Steel
Refrigerator Size 20 cu ft
Cooktop Burners 3
Number of Awnings 2
Axle Weight 7000 lbs
Garage Size 18 ft
LP Tank Capacity 30 lbs
Water Heater Type On Demand
AC BTU 30000 btu
TV Info LED TV; LR 49", Garage 32"
Awning Info 16' and 18' Power with LED Lights
Axle Count 3
Washer/Dryer Available Yes
Number of LP Tanks 2
Shower Type Shower w/Seat
Electrical Service 50 amp
VIN 573FM4635SBB03053
For more information, call us at 661-247-4549 or Contact Us
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ManuFacts
Grand Design Logo
In 2012, we started with a blank canvas to pursue that better way, a different way, than what had been done before. A company whose culture requires a long-term, personal connection with our customers, employees, and dealers – that company is Grand Design RV. Our business model of doing the right thing has led us to unparalleled years of growth.
 
Our local workforce has been hand-picked and has an excellent reputation for second-to-none industry craftsmanship, and our CEO and Senior Management actively work with the production facilities to help build the team and develop products.
 
At Grand Design we've raised the quality bar by putting every unit through a series of quality inspection gates during the manufacturing process. Once completed, the unit undergoes a comprehensive “final finish” inspection. Every one of our coaches is shipped to a PDI (Pre-Delivery Inspection) area where they are put through a rigorous 300+ point inspection checklist before being shipped to our dealers.  And, we back every one of our coaches with a 3-year limited structural warranty.  
 
At Grand Design our goal is simple – continue leading the industry with quality products while improving the customer’s RV experience before, during and after the sale. We strive for nothing less than customers for life and we would be honored to personally welcome you to the Grand Design RV family!

Happy Daze RV is not responsible for any misprints, typos, or errors found in our website pages. Any price listed excludes sales taxes, registration, tags and delivery fees. Manufacture pictures, specifications, and features may be used in place of actual units on our lot. To preserve the quality and mileage of our coaches, we only do test drives with a qualified offer to purchase.