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Keystone Montana 3121RL

Fifth wheelbuilt 2018–23Mixed build tierCommon on the used market
WHAT ONE COSTS
$76,000est. used (2023, 3 yr old)

Sticker was $122,693 in 2023. Out of production since 2023, so the used market is the only way to buy one. Estimate assumes a 2023 unit.

WHAT IT WEIGHS BEHIND YOUR TRUCK
~13,751 lbestimated as towed, for 2 people

dry weight 12,367 lb + fresh water (70 gal, full) 584 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 around15,280 lb (10% margin)
GVWR (the sticker maximum)16,350 lb
Tongue weight, loaded~2,613 lb (19%)
Cargo capacity3,983 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 3121RL'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
Length35.0 ft
Height (incl. A/C)13.3 ft
GVWR16,350 lb
Dry weight12,367 lb
Dry tongue weight2,350 lb
Cargo capacity3,983 lb
Sleeps4
Slide-outs3
Fresh water70 gal
Grey water88 gal
Black water49 gal

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

WHERE PEOPLE SLEEP
  • 1× King bed in front master(Permanent)—
  • 1× Convertible sofa in rear living(Convertible)—
HOW IT'S BUILT: 4/5
WallsLaminated fiberglass
FrameAluminum
RoofWalk-on
UnderbellyEnclosed

Keystone (Mixed tier): Keystone's flagship — the best construction in the Keystone stable (laminated walls, aluminum frame, long structural warranty), but Thor-era QC inconsistency keeps the line at mixed.

YEAR BY YEAR: WHAT CHANGED
YEARSGVWRDRYMSRP
2018–1916,380 lb12,367 lb$122,693
2020–2316,350 lb12,367 lb$122,693
  • 2018Introduced
  • 2020GVWR 16,380 to 16,350 lb; hitch 2,385 to 2,350 lb; sleeps rating 6 to 4
  • 2023Discontinued
FINDING ONE

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

OUR TAKE

The compact Montana — full luxury spec in a garage-friendlier 35-footer; the 2020 refresh dropped the sleeps rating to 4.

OTHER MONTANA FLOORPLANS
3100RL · 19,000 lb · sleeps 43120RL · 16,000 lb · sleeps 43123RL · 16,350 lb · sleeps 43230CK · 16,680 lb · sleeps 43231CK · 16,680 lb · sleeps 43531RE · 16,480 lb · sleeps 43532SP · 16,500 lb · sleeps 43700LK · 16,400 lb · sleeps 63740FK · 16,500 lb · sleeps 63760FL · 16,800 lb · sleeps 63761FL · 18,000 lb · sleeps 63762BP · 16,980 lb · sleeps 63763BP · 16,980 lb · sleeps 63780RL · 16,600 lb · sleeps 4the whole line →
Find one for sale

Live listings for the 3121RL 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 Montana line ↗

Is the 3121RL 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.