Grand Design Momentum M-Class 351MS vs KZ Sportster X 3411X
Grand Design · Toy Hauler
Grand Design Momentum M-Class 351MS
~$192,156
The difference that matters
At 39.9 ft apiece, the length is a wash, but the Momentum M-Class 351MS is the heavier and better-equipped rig. It weighs 15,760 lb dry with a 3,000 lb pin and a 19,000 lb GVWR, against 13,560 lb, 2,520 lb and 16,000 lb for the Sportster X 3411X. That gap matters when matching a truck to the pin.
For the weight, the Momentum brings an 11 ft garage separated from the living area, three slides, sleeping for six, 330 W of solar with a 50 A controller, a 20 cu ft 12 V fridge, a 60 gal fuel station, MORryde independent suspension and an R-40 roof. Tanks are 140 gal fresh, 52 gray and 104 black.
The Sportster X has a 100 in wide body with 102 in interior height, a 16 cu ft fridge, dual awnings and 100/50/88 gal tanks. Its cargo capacity is 2,440 lb.
- Grand Design Momentum M-Class 351MS
- Full-timers hauling toys who want solar, a big fresh tank and a garage walled off from the living space.
- KZ Sportster X 3411X
- Buyers who want a 40 ft toy hauler with a lighter pin weight and a tall, wide interior.
Weights
Weights
2027 maker figures
- Dry weight (UVW)
- 15,760 lb
- GVWR
- 19,000 lb
- Pin weight, dry
- 3,000 lb
- Cargo capacity (CCC)
- not published
3,240 lb between brochure dry weight and GVWR. Water (8.3 lb a gallon), food, gear, propane and dealer-added options all come out of it.
Weights
2027 maker figures
- Dry weight (UVW)
- 13,560 lb
- GVWR
- 16,000 lb
- Pin weight, dry
- 2,520 lb
- Cargo capacity (CCC)
- 2,440 lb
2,440 lb between brochure dry weight and GVWR. Water (8.3 lb a gallon), food, gear, propane and dealer-added options all come out of it.
Spec for spec
| Grand Design Momentum M-Class 351MS | KZ Sportster X 3411X | |
|---|---|---|
| Dry weight (UVW) | 15,760 lb | 13,560 lb |
| GVWR | 19,000 lb | 16,000 lb |
| Hitch / pin weight, dry | 3,000 lb | 2,520 lb |
| Cargo capacity (CCC / OCCC) | — | 2,440 lb |
| GVWR minus dry weight | 3,240 lb | 2,440 lb |
| Exterior length | 39.9 ft | 39.92 ft |
| Exterior height | 13.5 ft | 13.42 ft |
| Sleeps | 6 | — |
| Slide-outs | 3 | — |
| Fresh water | 140 gal | 100 gal |
| Gray water | 52 gal | 50 gal |
| Black water | 104 gal | 88 gal |
| Factory solar | 330 W | — |
Bold is the lighter or larger figure. A dash means the maker does not publish it.
To scale
- Grand Design Momentum M-Class 351MS · 39.9 ft long · 13′6″ tall
- KZ Sportster X 3411X · 39.92 ft long · 13′5″ tall
Grand Design Momentum M-Class 351MS
Full spec sheet, sources →
KZ Sportster X 3411X
Full spec sheet, sources →