Used 2020 Grand Design RV Momentum 399th for sale at Blue Fox RV in North Logan, UT. Sleeps 7, 44.8 ft long, 3 slides. Listed at $79,995.
Listing last updated .
2020 Grand Design RV Momentum 399th
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Built for the road, ready for your next trip.
- Dual Entry
- Full and Half Bath
- Exterior LED TV
- 13' Separate Garage
- Queen bed, with room to upgrade to a RV King
- Loft
- Sleeps 7 to 9 people
- Fold-Down Side Patio
- On board generator
If you are ready to play with your off-road toys, then it's time to hitch up this Momentum fifth wheel toy hauler after loading your toys in the 13' separate garage. You will be able to get cleaned up after getting muddy from the trails in the half bath in the garage or the sunken tub with skylight in the full bathroom up in the master suite. The kids can sit at the kitchen island with bar stools or relax on the theater seats while watching the 49" LED TV and fireplace. The fold-down side patio is going to be your favorite spot when summertime rolls around, and the exterior unobstructed pass-through storage compartment will allow you to bring along some lawn chairs that you can set up on the patio.
With any Grand Design Momentum toy hauler fifth wheel, you will enjoy extraordinary living and extreme playtime with the Weather-Tek insulation for four seasons of protection and a fully enclosed fuel pump station to keep the fun going the whole time. The Tuff-Ply garage flooring is gas and oil resistant, and it includes 2,500-LB flush-mount tie-downs to keep your toys secure while moving down the road. The interior includes color-changing LED accent lighting, a convection microwave, a central vacuum system with tools and a dust pan, and a OneControl 7" touchscreen control panel with app controls so that you can operate many of your RV's functions from wherever you want. Any Grand Design Momentum allows you to keep your active lifestyle no matter where you decide to stay!
Blue Fox Rv
390 W 2500 N North Logan Utah
435-890-4602
435-317-3625
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A short tour from our lot. We narrate the build details and the storage you can't see in photos.
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Towing & Dimensions 5
Tires & Wheels 9
Cargo 4
Quick Overview 8
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VisitNorth Logan, UT 84341
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Most of our buyers come from referrals because we sweat the small stuff after the sale.
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Is the 2020 Grand Design RV Momentum 399th still available?
Yes — as of June 24, 2026, this unit is on our lot in North Logan, UT. Last updated June 23, 2026.
How much is the 2020 Grand Design RV Momentum 399th?
$79,995. With $15,999 down at 6.99% APR over 180 months, that's about $575/mo. We accept trades — talk to us about your current unit when you visit.
What can tow this Grand Design RV Momentum?
1-ton truck with a proper heavy-duty towing package required — F-350+, Silverado 3500+, Ram 3500+. Dry weight is 15,900 lbs. Hitch/tongue weight is 3,400 lbs.
How many people can sleep in the Momentum?
7 people comfortably. Bed configuration: 2 queen, 1 bunk, 1 sofa-bed.
What's the warranty?
Basic warranty: 12. We'll go over all coverage details at the walkthrough before delivery.
Can I trade in my current RV?
Yes — we take trades every week, even if you don't buy from us. We'll give you a real offer once we see the RV. Call (435) 317-3625 or fill out the inquiry form below to get started.
How do I schedule a walkthrough?
Call (435) 317-3625, or fill out the inquiry form below. Same-day response during business hours.