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 $75,995.
Listing last updated .
2020 Grand Design RV Momentum 399th
Everything you'd ask on the lot.
Grand Design Momentum toy hauler 399TH highlights:
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
Floorplan
- Length
- 44 ft
- Slides
- 3
- Sleeps
- 7
RV specs, all in one place.
Towing & Dimensions
Tires & Wheels
Cargo
Quick Overview
Why buy your RV from us?
Most of our buyers come from referrals because we sweat the small stuff after the sale.
2020 Grand Design RV Momentum 399th
$75,995
- Call (435) 317-3625
- Visit North Logan, UT 84341
Quick answers, no sales pitch.
Is the 2020 Grand Design RV Momentum 399th still available?
Yes — as of August 25, 2026, this unit is on our lot in North Logan, UT. Last updated August 24, 2026.
How much is the 2020 Grand Design RV Momentum 399th?
$75,995. With $15,199 down at 6.99% APR over 180 months, that's about $546/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.
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.
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