Jayco Seismic 399
Fifth wheelbuilt 2025– (in production)Mixed build tierFindable on the used market
WHAT ONE COSTS
$132,000MSRP today
Still in production. A used 2023 would run roughly $77,900.
WHAT IT WEIGHS BEHIND YOUR TRUCK
~17,269 lbestimated as towed, for 2 people
dry weight 15,585 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 around19,190 lb (10% margin)
GVWR (the sticker maximum)21,000 lb
Tongue weight, loaded~3,618 lb (21%)
Cargo capacity5,415 lb
WHICH TOW VEHICLES IT FITS: 15 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 399's published weights changed mid-run. Fifth wheels also need a pickup bed and are held to the fifth-wheel rating where published.
The 80it doesn't fit
- Chevrolet Colorado / GMC Canyon (2.7 Turbo HO, tow pkg) '23-26: over by ~10,339 lb loaded
- Chevrolet Colorado / GMC Canyon (2.8 Duramax) '15-22: over by ~10,339 lb loaded
- Chevrolet Silverado / GMC Sierra 1500 (6.2 V8, max tow) '19-26: over by ~7,999 lb loaded
- Chevrolet Silverado / GMC Sierra 2500HD (Duramax) '11-19: over by ~979 lb loaded
- Chevrolet Silverado 1500 (max tow) '14-18: over by ~6,829 lb loaded
- Chevrolet Silverado EV (4WT) '24-26: over by ~6,019 lb loaded
- Chevrolet Suburban (5.3 V8, max tow) '21-26: no pickup bed (cannot hitch a fifth wheel)
- Chevrolet Tahoe (5.3 V8, max tow) '21-26: no pickup bed (cannot hitch a fifth wheel)
- Chevrolet Traverse (tow pkg) '18-26: no pickup bed (cannot hitch a fifth wheel)
- Chrysler Pacifica '17-26: no pickup bed (cannot hitch a fifth wheel)
- Dodge Durango (5.7 / 6.4 Hemi, tow pkg) '14-26: no pickup bed (cannot hitch a fifth wheel)
- Ford Bronco 4-dr (2.7 EcoBoost, tow pkg) '21-26: no pickup bed (cannot hitch a fifth wheel)
- Ford Expedition (3.5 EcoBoost, tow pkg) '25-26: no pickup bed (cannot hitch a fifth wheel)
- Ford Expedition (3.5 EcoBoost, tow pkg) '18-24: no pickup bed (cannot hitch a fifth wheel)
- Ford Explorer (3.0 EcoBoost, tow pkg) '20-26: no pickup bed (cannot hitch a fifth wheel)
- Ford F-150 (3.5 EcoBoost, max tow) '24-26: over by ~7,549 lb loaded
- Ford F-150 (3.5 EcoBoost, max tow) '15-20: over by ~6,559 lb loaded
- Ford F-150 (3.5 EcoBoost, max tow) '21-23: over by ~4,669 lb loaded
- Ford F-150 (3.5 EcoBoost, max tow) '11-14: over by ~7,099 lb loaded
- Ford F-150 Lightning (max trailer tow) '22-26: over by ~8,269 lb loaded
- Ford F-250 Super Duty (6.7 diesel, tow pkg) '17-19: over by ~1,069 lb loaded
- Ford F-250 Super Duty (6.7 diesel) '11-16: over by ~2,329 lb loaded
- Ford Maverick (2.0 EcoBoost, 4K tow pkg) '22-26: over by ~13,669 lb loaded
- Ford Ranger (2.3 EcoBoost, tow pkg) '19-23: over by ~10,519 lb loaded
- Ford Ranger (2.7 EcoBoost, tow pkg) '24-26: over by ~10,519 lb loaded
- Ford Transit (HD tow pkg) '15-26: no pickup bed (cannot hitch a fifth wheel)
- GMC Acadia (tow pkg) '20-26: no pickup bed (cannot hitch a fifth wheel)
- GMC Hummer EV Pickup '22-26: over by ~10,519 lb loaded
- GMC Sierra EV '24-26: over by ~6,469 lb loaded
- GMC Yukon / Yukon XL (5.3 V8, max tow) '21-26: no pickup bed (cannot hitch a fifth wheel)
- Honda Odyssey '18-26: no pickup bed (cannot hitch a fifth wheel)
- Honda Passport (AWD) '19-26: no pickup bed (cannot hitch a fifth wheel)
- Honda Pilot (AWD, tow pkg) '16-26: no pickup bed (cannot hitch a fifth wheel)
- Honda Ridgeline (AWD) '17-26: over by ~12,769 lb loaded
- Hyundai Palisade (tow pkg) '20-26: no pickup bed (cannot hitch a fifth wheel)
- Hyundai Santa Cruz (2.5T AWD) '22-26: over by ~12,769 lb loaded
- Jeep Gladiator (3.6 V6, max tow) '20-26: over by ~10,339 lb loaded
- Jeep Grand Cherokee (5.7 Hemi) '11-21: no pickup bed (cannot hitch a fifth wheel)
- Jeep Grand Cherokee (WL, tow pkg) '22-26: no pickup bed (cannot hitch a fifth wheel)
- Jeep Grand Cherokee L (5.7 Hemi) '21-26: no pickup bed (cannot hitch a fifth wheel)
- Jeep Grand Wagoneer (Hurricane, max tow) '22-26: no pickup bed (cannot hitch a fifth wheel)
- Jeep Wagoneer (Hurricane, max tow) '22-26: no pickup bed (cannot hitch a fifth wheel)
- Jeep Wrangler Unlimited 4-dr (tow pkg) '18-26: no pickup bed (cannot hitch a fifth wheel)
- Kia Telluride (tow pkg) '20-26: no pickup bed (cannot hitch a fifth wheel)
- Land Rover Defender '20-26: no pickup bed (cannot hitch a fifth wheel)
- Land Rover Discovery '17-26: no pickup bed (cannot hitch a fifth wheel)
- Lexus GX 550 (tow pkg) '24-26: no pickup bed (cannot hitch a fifth wheel)
- Lexus LX 600 '22-26: no pickup bed (cannot hitch a fifth wheel)
- Mazda CX-90 (3.3 turbo, tow pkg) '24-26: no pickup bed (cannot hitch a fifth wheel)
- Mercedes-Benz Sprinter '19-26: no pickup bed (cannot hitch a fifth wheel)
- Nissan Armada (3.5 twin-turbo, tow pkg) '25-26: no pickup bed (cannot hitch a fifth wheel)
- Nissan Armada (tow pkg) '17-24: no pickup bed (cannot hitch a fifth wheel)
- Nissan Frontier (3.8 V6, tow pkg) '22-26: over by ~10,834 lb loaded
- Nissan Pathfinder (tow pkg) '22-26: no pickup bed (cannot hitch a fifth wheel)
- Nissan Titan (5.6 V8, tow pkg) '17-24: over by ~8,484 lb loaded
- Nissan Titan XD (Cummins diesel) '16-19: over by ~5,829 lb loaded
- Ram 1500 (3.0 Hurricane, max tow) '25-26: over by ~6,819 lb loaded
- Ram 1500 (5.7 Hemi eTorque, max tow) '19-24: over by ~5,794 lb loaded
- Ram 1500 (5.7 Hemi, max tow) '11-18: over by ~7,709 lb loaded
- Ram 2500 (6.7 Cummins) '11-18: over by ~1,089 lb loaded
- Ram ProMaster '14-26: no pickup bed (cannot hitch a fifth wheel)
- Rivian R1S '22-26: no pickup bed (cannot hitch a fifth wheel)
- Rivian R1T '22-26: over by ~7,369 lb loaded
- Subaru Ascent '19-26: no pickup bed (cannot hitch a fifth wheel)
- Subaru Outback (XT / Wilderness) '20-26: no pickup bed (cannot hitch a fifth wheel)
- Tesla Cybertruck '24-26: over by ~7,369 lb loaded
- Tesla Model X (tow pkg) '16-26: no pickup bed (cannot hitch a fifth wheel)
- Tesla Model Y (tow pkg) '21-26: no pickup bed (cannot hitch a fifth wheel)
- Toyota 4Runner (4.0 V6) '11-24: no pickup bed (cannot hitch a fifth wheel)
- Toyota 4Runner (i-Force Max) '25-26: no pickup bed (cannot hitch a fifth wheel)
- Toyota Grand Highlander (i-Force Max) '24-26: no pickup bed (cannot hitch a fifth wheel)
- Toyota Highlander (tow pkg) '20-26: no pickup bed (cannot hitch a fifth wheel)
- Toyota Land Cruiser (i-Force Max) '24-26: no pickup bed (cannot hitch a fifth wheel)
- Toyota Sequoia (i-Force Max, tow pkg) '23-26: no pickup bed (cannot hitch a fifth wheel)
- Toyota Sienna '21-26: no pickup bed (cannot hitch a fifth wheel)
- Toyota Tacoma (i-Force Max, tow pkg) '24-26: over by ~11,419 lb loaded
- Toyota Tacoma (V6, tow pkg) '16-23: over by ~11,149 lb loaded
- Toyota Tundra (5.7 V8, tow pkg) '11-21: over by ~8,089 lb loaded
- Toyota Tundra (i-Force Max, tow pkg) '22-26: over by ~6,469 lb loaded
- Volkswagen Atlas (tow pkg) '18-26: no pickup bed (cannot hitch a fifth wheel)
These verdicts assume 2 people aboard with typical gear. See the margin for your truck and your crew →
THE SPECS
Length45.9 ft
Height (incl. A/C)13.3 ft
Width8.5 ft
GVWR21,000 lb
Dry weight15,585 lb
Dry tongue weight3,265 lb
Cargo capacity5,415 lb
Sleeps8
Fresh water106 gal
Grey water87 gal
Black water87 gal
Solar (standard)400 W
Awning21 ft
A missing row means the maker never published that figure: unknown, not zero.
WHERE PEOPLE SLEEP
- 1× Front bedroom king(Permanent)—
- 1× HappiJac electric-lift queen in garage(Stow-away)—
- 2× Garage opposing convertible sofas(Convertible)—
- 1× Free-standing dinette(Convertible)—
HOW IT'S BUILT: 4/5
WallsLaminated fiberglass
FrameSteel
RoofWalk-on
UnderbellyEnclosed
Jayco (Mixed tier): Jayco
YEAR BY YEAR: WHAT CHANGED
| YEARS | GVWR | DRY | MSRP |
|---|---|---|---|
| 2025 | 21,000 lb | 14,950 lb | $131,993 |
| 2026 | 21,000 lb | 14,950 lb | $131,993 |
- 2025Introduced
- 2027UVW 15,585 lb; CCC 5,415 lb
FINDING ONE
Findable: a few listed nationwide most weeks. Why: Jayco is a volume manufacturer; only 2 model years; still in production. Estimated from build volume and production span, not a count of live listings.
OUR TAKE
Best cargo capacity in the Jayco toy hauler range at 5,415 lb — a 13'6" garage that can actually carry what fits in it.
OTHER SEISMIC FLOORPLANS
Find one for sale
Live listings for the 399 on the big marketplaces. Each search opens pre-filled with this exact floorplan:
Inventory varies by site and day. Slim pickings? search the whole Seismic line ↗
Is the 399 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.