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Keystone Carbon 403

Fifth wheelbuilt 2018–19Mixed build tierFindable on the used market
WHAT ONE COSTS
$45,100est. used (2019, 7 yr old)

Sticker was $76,819 in 2019. Out of production since 2019, so the used market is the only way to buy one. Estimate assumes a 2019 unit.

WHAT IT WEIGHS BEHIND YOUR TRUCK
~15,774 lbestimated as towed, for 2 people

dry weight 14,090 lb + fresh water (106 gal, full) 884 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 around17,530 lb (10% margin)
GVWR (the sticker maximum)19,000 lb
Tongue weight, loaded~3,818 lb (24%)
Cargo capacity4,910 lb
WHICH TOW VEHICLES IT FITS: 18 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 403'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 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 77it doesn't fit

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

THE SPECS
Length43.5 ft
Height (incl. A/C)13.5 ft
Width8.3 ft
GVWR19,000 lb
Dry weight14,090 lb
Dry tongue weight3,410 lb
Cargo capacity4,910 lb
Sleeps8
Slide-outs3
Axles2
Fresh water106 gal
Grey water82 gal
Black water82 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(Permanent)—
  • 1× Loft bunk mat(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
  • 2018Introduced
FINDING ONE

Findable: a few listed nationwide most weeks. Why: Keystone is a volume manufacturer; only 2 model years. Estimated from build volume and production span, not a count of live listings.

OUR TAKE

Two-year-only big-garage plan between the 387 and 417.

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 6338 · 16,820 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 6the whole line →
Find one for sale

Live listings for the 403 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 403 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.