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Keystone Sprinter 3550MLS

Fifth wheelbuilt 2018–21Mixed build tierFindable on the used market
WHAT ONE COSTS
$45,400est. used (2021, 5 yr old)

Sticker was $74,065 in 2021. Out of production since 2021, so the used market is the only way to buy one. Estimate assumes a 2021 unit.

WHAT IT WEIGHS BEHIND YOUR TRUCK
~12,532 lbestimated as towed, for 2 people

dry weight 11,056 lb + fresh water (81 gal, full) 676 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 around13,925 lb (10% margin)
GVWR (the sticker maximum)14,000 lb
Tongue weight, loaded~2,499 lb (20%)
Cargo capacity2,944 lb
WHICH TOW VEHICLES IT FITS: 20 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 3550MLS'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-150 (3.5 EcoBoost, max tow) '21-2314,000 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 75it doesn't fit

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

THE SPECS
Length39.0 ft
Height (incl. A/C)13.2 ft
Width8.3 ft
GVWR14,000 lb
Dry weight11,056 lb
Dry tongue weight2,205 lb
Cargo capacity2,944 lb
Sleeps4
Slide-outs4
Axles2
Fresh water81 gal
Grey water78 gal
Black water44 gal
Air conditioning15,000 BTU

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

WHERE PEOPLE SLEEP
  • 1× rear master suite king bed(Permanent)70×80
  • 1× tri-fold sleeper sofa(Convertible)—
HOW IT'S BUILT: 4/5
WallsLaminated fiberglass
FrameAluminum
RoofWalk-on
UnderbellyEnclosed

Keystone (Mixed tier): Keystone RV

YEAR BY YEAR: WHAT CHANGED
YEARSGVWRDRYMSRP
2018–2014,000 lb11,040 lb$74,065
202114,000 lb11,056 lb$74,065
  • 2018Introduced as the 3550FWMLS
  • 2021Renamed 3550MLS and discontinued
FINDING ONE

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

OUR TAKE

Mid-living with an entertaining kitchen and a rear master suite.

OTHER SPRINTER FLOORPLANS
25ML · 11,970 lb · sleeps 429BH · 11,770 lb · sleeps 830RL · 12,210 lb · sleeps 63150FWRLS · 12,900 lb · sleeps 63190RLS · 12,900 lb · sleeps 631MB · 11,910 lb · sleeps 831TB · 12,100 lb · sleeps 73210RLS · 14,100 lb · sleeps 432BH · 11,930 lb · sleeps 103340FLS · 14,000 lb · sleeps 63500RDB · 13,900 lb · sleeps 63520RDS · 13,900 lb · sleeps 43530DEN · 14,000 lb · sleeps 63560RLB · 14,000 lb · sleeps 6the whole line →
Find one for sale

Live listings for the 3550MLS 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 Sprinter line ↗

Is the 3550MLS 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 manufacturer spec sheets, retrieved 2026-07.