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Grand Design Solitude 377MBS

Fifth wheelbuilt 2017–20Better build tierFindable on the used market
WHAT ONE COSTS
$57,000est. used (2020, 6 yr old)

Sticker was $92,713 in 2020. Out of production since 2020, so the used market is the only way to buy one. Estimate assumes a 2020 unit.

WHAT IT WEIGHS BEHIND YOUR TRUCK
~14,776 lbestimated as towed, for 2 people

dry weight 13,200 lb + fresh water (93 gal, full) 776 lb + propane + battery 200 lb + gear for 2 600 lb. Brochure dry weight omits water, propane, batteries and your gear; this estimate doesn't.

You want a tow rating around16,420 lb (10% margin)
GVWR (the sticker maximum)16,800 lb
Tongue weight, loaded~3,078 lb (21%)
WHICH TOW VEHICLES IT FITS: 19 OF 95

Judged the way the app judges: estimated loaded weight against each vehicle's rating less a 10% margin, per model year, because the 377MBS's published weights changed mid-run. Fifth wheels also need a pickup bed and are held to the fifth-wheel rating where published.

VEHICLETOW RATINGVERDICT
Chevrolet Silverado / GMC Sierra 2500HD (Duramax, max tow) '24-2622,500 lbfits, loaded, with 10% margin
Chevrolet Silverado / GMC Sierra 2500HD (Duramax) '20-2318,510 lbfits, loaded, with 10% margin
Chevrolet Silverado / GMC Sierra 2500HD (Duramax) '11-1918,100 lbfits, loaded, with 10% margin
Chevrolet Silverado / GMC Sierra 3500HD (Duramax DRW, gooseneck) '20-2636,000 lbfits, loaded, with 10% margin
Chevrolet Silverado / GMC Sierra 3500HD (Duramax DRW, gooseneck) '11-1923,300 lbfits, loaded, with 10% margin
Ford F-250 Super Duty (6.7 diesel, gooseneck) '20-2222,800 lbfits, loaded, with 10% margin
Ford F-250 Super Duty (6.7 diesel, tow pkg) '17-1918,000 lbfits, loaded, with 10% margin
Ford F-250 Super Duty (6.7 diesel) '11-1616,600 lbfits, loaded, with 10% margin
Ford F-250 Super Duty (6.7 HO diesel, gooseneck) '23-2623,000 lbfits, loaded, with 10% margin
Ford F-350 Super Duty (6.7 diesel DRW, gooseneck) '17-1932,500 lbfits, loaded, with 10% margin
Ford F-350 Super Duty (6.7 diesel DRW, gooseneck) '20-2237,000 lbfits, loaded, with 10% margin
Ford F-350 Super Duty (6.7 diesel DRW, gooseneck) '11-1621,600 lbfits, loaded, with 10% margin
Ford F-350 Super Duty (6.7 HO diesel DRW, gooseneck) '23-2638,000 lbfits, loaded, with 10% margin
Ford F-450 Super Duty (6.7 HO diesel DRW, gooseneck) '23-2640,000 lbfits, loaded, with 10% margin
Ram 2500 (6.7 Cummins HO) '19-2620,000 lbfits, loaded, with 10% margin
Ram 2500 (6.7 Cummins) '11-1817,980 lbfits, loaded, with 10% margin
Ram 3500 (6.7 Cummins DRW, gooseneck) '13-1831,210 lbfits, loaded, with 10% margin
Ram 3500 (6.7 Cummins HO DRW, gooseneck) '25-2636,610 lbfits, loaded, with 10% margin
Ram 3500 (6.7 Cummins HO DRW, gooseneck) '19-2437,090 lbfits, loaded, with 10% margin
The 76it doesn't fit

These verdicts assume 2 people aboard with typical gear. See the margin for your truck and your crew →

THE SPECS
Length41.3 ft
Height (incl. A/C)13.4 ft
Width8.4 ft
GVWR16,800 lb
Dry weight13,200 lb
Dry tongue weight2,750 lb
Sleeps10
Slide-outs4
Axles2
Fresh water93 gal
Grey water100 gal
Black water50 gal
Air conditioning15,000 BTU

A missing row means the maker never published that figure: unknown, not zero.

WHERE PEOPLE SLEEP
  • 1× Front queen bed, king optional(Permanent)60×80
  • 2× Mid-bunk room bunks (sizes unpublished)(Permanent)—
  • 2× Double tri-fold hide-a-bed sofas(Convertible)—
  • 1× Dinette converts to a bed(Convertible)—
HOW IT'S BUILT: 4/5
WallsLaminated fiberglass
FrameAluminum
RoofWalk-on
UnderbellyEnclosed

Grand Design (Better tier): Solitude is Grand Design's full-profile flagship: R-11 welded-aluminum laminated walls, 101" widebody chassis, MORryde independent suspension and 17.5" H-rated tires — genuine full-time-capable construction.

YEAR BY YEAR: WHAT CHANGED
YEARSGVWRDRYMSRP
201616,000 lb13,200 lb$92,713
2017–2016,800 lb13,200 lb$92,713
  • 2016Predecessor 377MB introduced with a 16,000 lb GVWR
  • 2017Renamed 377MBS; GVWR raised to 16,800 lb
  • 2021Replaced by the 378MBS
FINDING ONE

Findable: a few listed nationwide most weeks. Estimated from build volume and production span, not a count of live listings.

OUR TAKE

Mid-bunk Solitude rated for ten — the biggest sleeps count the line has offered. MSRP not published in surviving sources.

OTHER SOLITUDE FLOORPLANS
2930RL · 15,000 lb · sleeps 2305RE · 16,000 lb · sleeps 4310GK · 19,000 lb · sleeps 43330RE · 16,800 lb · sleeps 6344GK · 16,800 lb · sleeps 6345GK · 16,800 lb · sleeps 43460FL · 16,800 lb · sleeps 63540GK · 16,800 lb · sleeps 43550BH · 16,800 lb · sleeps 8366DEN · 16,000 lb · sleeps 5370DV · 19,000 lb · sleeps 4372WB · 16,800 lb · sleeps 4373FB · 16,800 lb · sleeps 43740BH · 16,800 lb · sleeps 8the whole line →
Find one for sale

Live listings for the 377MBS on the big marketplaces. Each search opens pre-filled with this exact floorplan:

RV Trader ↗Camping World ↗FB Marketplace ↗Google ↗

Inventory varies by site and day. Slim pickings? search the whole Solitude line ↗

Is the 377MBS your #1, or just a spec sheet?

These are the facts. Whether it beats the other six thousand rigs for you depends on what you care about. Set your priorities as sliders, switch on your hard limits, and watch the whole market re-rank around them. Every exclusion explained, every margin shown.

See where it ranks for you →

Data compiled from dealer and aggregator listings, retrieved 2026-07.