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Keystone Sprinter 3670FLS

Fifth wheelbuilt 2021– (in production)Mixed build tierCommon on the used market
WHAT ONE COSTS
$91,100MSRP today

Still in production. A used 2023 would run roughly $53,800.

WHAT IT WEIGHS BEHIND YOUR TRUCK
~12,951 lbestimated as towed, for 2 people

dry weight 11,525 lb + fresh water (75 gal, full) 626 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 around14,390 lb (10% margin)
GVWR (the sticker maximum)14,000 lb
Tongue weight, loaded~2,787 lb (22%)
Cargo capacity2,475 lb
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 3670FLS's published weights held steady. 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
Length40.3 ft
Height (incl. A/C)13.3 ft
Width8.3 ft
GVWR14,000 lb
Dry weight11,525 lb
Dry tongue weight2,480 lb
Cargo capacity2,475 lb
Sleeps8
Slide-outs4
Axles2
Fresh water75 gal
Grey water102 gal
Black water34 gal
Air conditioning15,000 BTU

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

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

Keystone (Mixed tier): Keystone RV

YEAR BY YEAR: WHAT CHANGED
  • 2021Introduced
FINDING ONE

Common: usually several for sale within a day’s drive. Why: Keystone is a volume manufacturer; still in production. Estimated from build volume and production span, not a count of live listings.

OUR TAKE

Front living with a full dinette and stackable washer/dryer prep.

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 63550MLS · 14,000 lb · sleeps 4the whole line →
Find one for sale

Live listings for the 3670FLS 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 3670FLS 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.