Skip to main content Skip to navigation

Browse RV floor plans

Inventory Dealers

Class A motorhomes
Class C motorhomes
Class B vans
Fifth wheel trailers
Travel trailers
Pop-up campers
Advanced search
Floor plan wizard
Inventory

Browse popular layouts & features

Class A motorhomes

… with bunk beds
… with two bedrooms
… with bath and a half
… with two full bathrooms
… with bunk over cab
… with rear bathroom

Browse all features →

Class B vans

… with King size bed
… with rear twin beds
… with Murphy bed
… with rear bathroom
… with dual twin beds

Browse all features →

Class C motorhomes

… with bunk over cab
… with bunk beds
… with rear bathroom
… with rear twin beds
… with Murphy bed
… with outdoor kitchen
… with outdoor TV

Browse all features →

Fifth wheel trailers

… with bath and a half
… with two bathrooms
… with bunk beds
… with two bedrooms
… with side patio
… with rear patio
… with outdoor kitchen
… with washer/dryer
… with front living

Browse all features →

Travel trailers

… with bunk beds
… with two bedrooms
… with Murphy bed
… with outdoor kitchen
… with rear bath
… with front bedroom

Browse all features →

Popup campers

under $10k
under $15k
under 2,000 lbs
under 3,000 lbs

Browse all features →

RV dealers by metro area

Los Angeles Dallas–Fort Worth Houston Atlanta Phoenix Tampa Bay Orlando Denver Chicago Seattle Nashville Toronto Browse all metro areas →

Quick links

About
Contact
Guides
Privacy policy
Terms of service

Connect

Stay updated

Fax

© 2026 RV Envy. All rights reserved.

RV dealer websites and CRM powered byRV Envy

DashboardInventory Guides

2023 Momentum 399TH Fifth Wheel for sale | RV Envy

Home
Fifth wheel trailers
Grand Design
Momentum

Grand Design Momentum 399TH

Toy hauler, side patio, bath and a half, bar seating

Front bedroom
Side patio
Bath and a half
Walk-thru bath
Loft
Bar seating
Toy hauler

MSRP

$153,081

Browse inventory (12)

Grand Design Momentum 399TH floor plan

Grand Design Momentum 399TH floor plan

Key facts

MSRP: $153,081
Length: 43 ft 1 in
Max weight: 20,000 lbs
Sleeps: 9

RV Envy's expert take

We like...

Side patio

Things to consider...

TV doesn't face couch
Tight quarters in bathrooms

Videos

Find a Grand Design Momentum 399TH

See it in person or find a great deal nationwide.

Want to remember this floor plan?

Grand Design Momentum 399TH overview

Front bedroom
Side patio
Bath and a half
Walk-thru bath
Loft
Bar seating
Toy hauler

Key facts

MSRP: $153,081
Length: 43 ft 1 in
Max weight: 20,000 lbs
Sleeps: 9

Specs

Dimensions

Length: 43 ft 1 in
Height: 13 ft 5 in
Width: 8 ft 5 in
Slideouts: 3

Tanks & capacities

Fresh water: 140 gal
Gray water: 104 gal
Black water: 104 gal

Weight & towing

Dry weight: 15,900 lbs
GVWR: 20,000 lbs
Hitch weight: 3,400 lbs

1 ton truck required

New Ford F-350, RAM 3500, Sierra 3500, or bigger

Based on overall weight and weight directly on tow vehicle's hitch and a new model tow vehicle. Please consult with a professional.

Accommodations

Sleeps: 9

Download brochure

Available years

2024 2023 2022 2021

On this page...