01 What makes it unique
The 21G is the smallest way into a G-Class garage, and it is a genuine toy hauler rather than a trailer with a ramp: a full-sized rear ramp door, a flat garage floor with no wheel wells, rear-ramp loading lights with a back-up function, 2,500-pound tie-downs anchored into the chassis and a 30-gallon fuel station with interior and exterior gauges — all standard across the G-Class travel-trailer roster. At twenty-six feet eleven inches on one slide, it is the only single-slide plan of the seven. Laminated aluminum walls at R-7 sit under a 5-inch radius wood-framed R-40 roof with a double-insulated front cap, and the underbelly is heated and enclosed with suspended tanks.
Grand Design publishes 11,000 pounds of GVWR against 7,280 dry, so the payload is 3,720 pounds — more than the entry Momentum fifth wheel's 3,090, in a trailer half its weight. The dry tongue is 1,056 pounds, which is the number to think hardest about: it is a comfortable half-ton figure at rest, but a toy hauler's tongue weight climbs with everything ahead of the axles, and an 11,000-pound loaded trailer will not stay at 1,056. Weigh it loaded and read your vehicle's door-jamb placard before you commit to a half-ton.
02 Full specifications
Dimensions
- Exterior length
- 26 ft 11 in
- Exterior width
- 8 ft 5 in
- Width, slides out
- 11 ft 4 in
- Exterior height
- 12 ft 4 in
- Interior height
- 7 ft 7 in
- Garage / flex length
- 14 ft*
Weights
- Dry / unit base weight (UVW)
- 7,280 lbs
- GVWR (max loaded)
- 11,000 lbs
- Net cargo / payload
- 3,720 lbs
- Dry tongue weight
- 1,056 lbs
Capacities
- Fresh water
- 90 gal
- Grey water
- 74 gal
- Black water
- 39 gal
- LP gas
- 40 lbs · 2 tanks
- Refrigerator
- 8 cu. ft.
Construction
- Sidewalls
- Laminated aluminum framed (R-7)
- Roof
- 5″ radius wood framed (R-40*) · double-insulated roof and front cap
- Ramp door
- Laminated aluminum framed (R-12)
- Front cap
- Fiberglass w/ paint · 48″ LED front cap lighting
- Underbelly
- Heated and enclosed w/ suspended tanks
Running gear
- Hitch
- Bumper pull
- Wheel wells
- None — flat garage floor
- Spare
- Full-sized spare tire and carrier
- Roof access
- Folding roof ladder · walk-on roof
Garage
- Garage / flex length
- 14 ft*
- Garage insulation
- R-30
- Ramp
- Full-sized rear ramp door · rear-ramp loading lights w/ back-up function
- Tie-downs
- 2,500 lb tie-downs anchored into the chassis
- Fuel station
- 30 gal
Galley & systems
- Refrigerator
- 8 cu. ft. 12-volt
- Air conditioning
- 15,000 BTU
- Furnace
- 30,000 BTU
- Water heater
- Tankless
- Solar
- 220W roof-mounted panel · 30 AMP controller
- Shower
- 27 X 36
Sleeping & layout
- Sleeps
- 6
- Slides
- 1
- Awnings
- 1 · 19 ft
- Hitch type
- Bumper pull
- Primary bed
- 60 X 80 Queen Bed
03 The Momentum floorplan family
Momentum is Grand Design's toy-hauler family, and it spans four rosters across both tow types. The full-size Momentum fifth wheel is the flagship — a 101-inch wide-body coach on MORryde independent suspension with disc brakes, carrying a 60-gallon dual fuel station. The Momentum G-Class fifth wheel sits below it on MORryde CRE3000 suspension and a Rotoflex pin box with a 30-gallon fuel station, and the G-Class travel trailer puts that same garage behind a bumper pull. The Momentum MAV is the compact end — the lightest and cheapest way into a Momentum garage, and the one roster with no fuel station at all. The 21G on this page is highlighted; each other profiled plan links to its own page. The full MY2027 catalogue runs to 28 floorplans across the four rosters; eight are profiled in depth here and the rest are catalogued on the line hub with their weights.
| Floorplan | Roster | Type | Length | Garage | Sleeps | Notable |
|---|---|---|---|---|---|---|
| 344M | Momentum | 5W | 39′ 11″ | 11 ft | 6 | Entry Momentum — lowest GVWR of the ten, tightest payload |
| 392M | Momentum | 5W | 45′ 11″ | 17 ft | 9 | Sleeps nine, longest fifth-wheel garage in the family |
| 320G | Momentum G-Class | 5W | 36′ 3″ | 11 ft | 6 | Entry G-Class fifth wheel — lowest GVWR of the six |
| 394G | Momentum G-Class | 5W | 44′ 11″ | 15 ft* | 7 | Top G-Class GVWR, biggest G-Class payload, triple awning |
| 21G | Momentum G-Class | TT | 26′ 11″ | 14 ft* | 6 | Entry G-Class trailer — only single-slide, lowest GVWR |
| 30G | Momentum G-Class | TT | 34′ 10″ | 20 ft 7 in | 7 | Longest garage in the whole Momentum family |
| 17MAV | Momentum MAV | TT | 22′ 11″ | 11 ft 6 in | 2 | Lightest and cheapest Momentum built |
| 28MAV | Momentum MAV | TT | 33′ 11″ | 10 ft 4 in | 6 | Top of the MAV range — the only MAV with a slide-out |
The Momentum G-Class travel trailer brings the G-Class garage to a bumper-pull, for buyers who want a real toy hauler without an in-bed hitch. Laminated aluminum walls, a full-sized rear ramp door, a flat no-wheel-well garage floor and a 30-gallon fuel station are standard across the roster. Tongue weights are factory dry figures — weigh the loaded trailer and confirm against your vehicle's door-jamb placard. Additional G-Class travel-trailer floorplans are catalogued on the line hub.
04 What owners & reviewers report
The only single-slide G-Class trailer
One slide against two on every other plan in the roster, and the lowest GVWR of the seven at 11,000 pounds.
Fourteen-foot garage in under twenty-seven feet
More than half the trailer is cargo space. The floor is flat — the roster carries no wheel wells in the garage.
Garage length published without a unit
The factory prints a bare 14 with no unit where other plans print 13 feet 6 inches. Feet is the only consistent reading, but it is our reading, so it is flagged.
A 1,056-pound dry tongue is a starting figure
Loaded to its 11,000-pound GVWR with cargo ahead of the axles, the real tongue weight will be well above it. Check the door-jamb placard, not the brochure.
05 How it compares
The entry Cyclone travel trailer — 11,700 pounds of GVWR with a published 4,255-pound cargo capacity, sleeping four, profiled here.
Four feet shorter, 1,738 pounds lighter dry and twenty-six thousand dollars cheaper — but no fuel station, and it sleeps two.
Eight feet longer with the longest garage in the whole Momentum family, a king bed and two slides.