2024 Grand Design Momentum 399TH vs 2025 Grand Design Momentum G-Class 28G

Detailed Comparison

The 2024 Grand Design Momentum 399TH goes up against the 2025 Grand Design Momentum G-Class 28G in this detailed comparison. Each has distinct advantages worth considering.

Dimensionally, you're looking at 28.0 ft for the Grand Design Momentum 399TH and 43.0 ft for the Grand Design Momentum G-Class 28G. The Grand Design Momentum G-Class 28G carries an extra 3,700 lbs, which affects tow vehicle requirements and fuel economy.

The Grand Design Momentum 399TH sleeps 9 while the Grand Design Momentum G-Class 28G accommodates 10.

For boondocking enthusiasts, tank sizes matter. Fresh water capacity goes to the Grand Design Momentum 399TH at 68 gallons versus 56 gallons. Solar-wise, you get 200W on the Grand Design Momentum 399TH and 150W on the Grand Design Momentum G-Class 28G. Battery banks are 150 Ah and 150 Ah.

At $61,000 MSRP for the Grand Design Momentum 399TH and $70,000 for the Grand Design Momentum G-Class 28G, the Grand Design Momentum 399TH saves you $9,000.

If you're traveling with a family, look for the model with more sleeping positions and better storage. Boondockers: look at the fresh water capacity and solar/battery systems — they determine how long you can stay out. For the full-time RV lifestyle, every gallon of tank capacity and every inch of counter space counts.

Whichever you choose, you'll be getting a capable rig. Just make sure to inspect one in person before signing.