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Keystone Carbon 338

Fifth wheelbuilt 2021–26Mixed build tierCommon on the used market
WHAT ONE COSTS
$71,200est. used (2026, 1 yr old)

Sticker was $96,990 in 2024. Out of production since 2026, so the used market is the only way to buy one. Estimate assumes a 2026 unit.

WHAT IT WEIGHS BEHIND YOUR TRUCK
~13,680 lbestimated as towed, for 2 people

dry weight 12,096 lb + fresh water (94 gal, full) 784 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 around15,200 lb (10% margin)
GVWR (the sticker maximum)16,820 lb
Tongue weight, loaded~3,189 lb (23%)
Cargo capacity4,724 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 338'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
Length35.9 ft
Height (incl. A/C)13.2 ft
Width8.3 ft
GVWR16,820 lb
Dry weight12,096 lb
Dry tongue weight2,820 lb
Cargo capacity4,724 lb
Sleeps6
Slide-outs2
Axles2
Fresh water94 gal
Grey water82 gal
Black water44 gal
Air conditioning15,000 BTU
Solar (standard)200 W
Awning19 ft

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

WHERE PEOPLE SLEEP
  • 1× Front queen bed(Permanent)—
  • 2× Garage electric bed over opposing sofas(Convertible)—
HOW IT'S BUILT: 4/5
WallsLaminated fiberglass
FrameAluminum
RoofWalk-on
UnderbellyEnclosed

Keystone (Mixed tier): Carbon Toy Hauler

YEAR BY YEAR: WHAT CHANGED
YEARSGVWRDRYMSRP
2021–2316,820 lb12,096 lb$96,990
2024–2616,820 lb12,281 lb$96,990
  • 2021Introduced
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

Short-garage fifth wheel replacing the 337.

OTHER CARBON FLOORPLANS
27 · 11,145 lb · sleeps 629WFO · 13,000 lb · sleeps 630WFO · 13,000 lb · sleeps 6310 · 16,710 lb · sleeps 632 · 13,000 lb · sleeps 633 · 13,000 lb · sleeps 6330 · 16,765 lb · sleeps 6337 · 16,755 lb · sleeps 6340 · 17,000 lb · sleeps 6347 · 17,000 lb · sleeps 6348 · 17,000 lb · sleeps 7349 · 16,720 lb · sleeps 635 · 13,000 lb · sleeps 6357 · 17,000 lb · sleeps 6the whole line →
Find one for sale

Live listings for the 338 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 Carbon line ↗

Is the 338 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.