01 What makes it unique
Keystone publishes three weights for the Hampton 388FKL: a shipping weight of 11,515 lb, a carrying capacity of 3,485 lb and a hitch weight of 1,585 lb. Those are Keystone’s own terms, and this page keeps them. Keystone does not call the first figure dry or unloaded weight, does not say the hitch figure is measured dry, and publishes no GVWR for any Hampton floorplan, so none of the three is renamed here and no loaded rating is worked out from them. The trailer’s own federal weight label, inside the door, is the document that carries its UVW, cargo capacity and GVWR.
Tank capacities are 54 gal fresh, 120 gal gray and 40 gal waste, as Keystone lists them. Fresh water weighs about 8.3 lb per US gallon, so a full fresh tank is roughly 448 lb on the road before anything else is loaded. The tire size Keystone lists is ST235/80R16G.
Against the 3 Hampton floorplans profiled here, this one is the 1st by Keystone’s shipping weight, in a range from 11,515 lb (388FKL) to 12,072 lb (378DBB). Every figure in that comparison comes from the same Keystone page type for the same model year, so the comparison inside the series is like for like.
Every number on this page was read on 5 Nov 2026 from Keystone’s own floorplan page for the Hampton 388FKL. That page carries no model year, so the year comes from the roster page that links it, which lists the Hampton floorplans under the heading “2027 Floorplans”. Keystone notes that its website reflects the most recent production run and that features and specifications change during the year.
How the 388FKL differs from the other two Hampton floorplans. Most distinctive first. How these ranks are worked out.
- Shipping weight (Keystone’s term), 11,515 lb: lightest of three; next is the 372FDB (11,666 lb).
- Carrying capacity (Keystone’s term), 3,485 lb: largest of three; next is the 372FDB (3,334 lb).
- Length, 42 ft 4 in: longest of three; next is the 372FDB (41 ft 4 in).
- Exterior height, 13 ft 6 in: tallest of three; next is the 378DBB (13 ft).
- Sleeping capacity, 7: largest of three; next are the 372FDB and 378DBB (4).
- Hitch weight as Keystone lists it, 1,585 lb: second-lightest of three, between the 378DBB (1,508 lb) and the 372FDB (1,974 lb).
- Hitch weight as a share of shipping weight, 13.8%: second-smallest of three, between the 378DBB (12.5%) and the 372FDB (16.9%).
Next to the 372FDB, the nearest heavier floorplan by shipping weight, the 388FKL is 151 lb lighter by shipping weight, has 151 lb more carrying capacity, has a hitch weight 389 lb lighter, is 1 ft longer, stands 7 in taller, has a fresh tank 4 gal larger, has a grey tank 42 gal larger and sleeps three more.
02 Full specifications
Dimensions
- Exterior length
- 42' 4"
- Exterior height
- 13' 6"
- Exterior width
- Not published by Keystone
Weights
- Dry / unit base weight (UVW)
- Not published by Keystone
- GVWR (max loaded)
- Not published by Keystone
- Shipping weight (Keystone’s term)
- 11,515 lb
- Carrying capacity (Keystone’s term)
- 3,485 lb
- Hitch weight, as Keystone lists it
- 1,585 lb
Capacities
- Fresh water
- 54 gal
- Gray water
- 120 gal
- Waste water
- 40 gal
Running gear
- Hitch type
- Bumper pull
- Tire size
- ST235/80R16G
Sleeping & layout
- Sleeps
- 7
- Propane
- 60 lb
- Refrigerator
- 18 Cu. cu ft
How these published figures sit against the rest of the catalogue: travel trailer tongue weight by size; fresh, grey and black tank sizes; camper trailer size chart.
Towing it
Can’t check: Keystone publishes no GVWR. A tow check needs the GVWR, the most the trailer may weigh loaded, and Keystone prints none for this floorplan, so this site does not work one out. Read the GVWR on the trailer’s own federal weight label and hold it against your tow vehicle’s ratings.
03 The Hampton floorplan family
Keystone lists 3 Hampton floorplans for 2027. 3 have a complete Keystone figure set and no existing page here, and are profiled, from 11,515 lb to 12,072 lb shipping weight; the others are catalogued on this page with the reason against each. Keystone publishes shipping weight, carrying capacity and hitch weight for these trailers, and no GVWR.
Keystone lists 3 Hampton floorplans for 2027. 3 are profiled here; the rest are catalogued with the reason against each.
04 Notes on this floorplan
What Keystone does not publish for the Hampton
No GVWR, no unloaded (dry) weight under that name, no dry hitch weight and no exterior width appear on Keystone’s floorplan pages for this series, so those rows read as not published. Nothing is filled from a sibling floorplan, a different model year or a dealer listing.
Read the label on the trailer
Federal rules put a load-carrying label inside every RV trailer: its unloaded weight with full propane, its cargo carrying capacity and its GVWR (49 CFR 571.110 and 571.120). On a Hampton those figures come from the trailer, not from this page, and they govern the towing decision.
05 How it compares
11,666 lb shipping weight and 3,334 lb carrying capacity, against this plan’s 11,515 lb and 3,485 lb.
07 Where this floorplan sits
Closest sibling: the Hampton 378DBB, nearest on the published figures. It differs on 3 of the 5 fields both publish (this plan first): length 42 ft 4 in vs 40 ft 11 in; sleeps 7 vs 4; hitch weight 1,585 lb vs 1,508 lb. They match on fresh tank and grey tank.
| Hampton plans | This plan | Position, low to high | Range |
|---|---|---|---|
| Hitch weight (lb) | 1,585 | 2 of 3 | 1,508–1,974 |
| Length | 42 ft 4 in | 3 of 3 | 40 ft 11 in–42 ft 4 in |
| Fresh tank (gal) | 54 | 2–3 of 3 | 50–54 |
| Grey tank (gal) | 120 | 2–3 of 3 | 78–120 |
| Sleeps | 7 | 3 of 3 | 4–7 |
| Nearest Hampton siblings | Length | Sleeps | Dry (lb) | GVWR (lb) | CCC (lb) | Hitch (lb) | Fresh (gal) |
|---|---|---|---|---|---|---|---|
| Hampton 388FKL | 42 ft 4 in | 7 | — | — | — | 1,585 | 54 |
| Hampton 378DBB | 40 ft 11 in | 4 | — | — | — | 1,508 | 54 |
| Hampton 372FDB | 41 ft 4 in | 4 | — | — | — | 1,974 | 50 |
All 3 Hampton floorplans: Hampton line hub.
08 Common questions about the 388FKL
What is the tongue weight of the 388FKL?
1,585 lb as published.
How many people does the 388FKL sleep?
It is rated to sleep 7. No other Hampton floorplan here is rated for more.
What are the tank capacities on the 388FKL?
Fresh 54, grey 120 gallons.
How long is the 388FKL?
42' 4" overall, tongue or pin box included.
From the figures above.
09 What this page publishes, and what it does not
8 of the 18 fields this catalogue tracks are published for the 388FKL. Not published: dry weight, GVWR, cargo capacity (CCC), exterior width, interior height, black tank, slide count, axle count, awning, air conditioning.
Sourcing rules: methodology.
10 Manuals & documents
Sources: keystonerv.com (linked below); the full source note is at the foot of the page.
11 NHTSA safety record
NHTSA holds 5 recall campaigns and 1 owner complaint (model years 2005 on) against the Reign, Hampton & Sprout line (a recall and a complaint are not the same thing).
Too few reports to show a pattern. 1 complaint has been filed on this line — not enough to say what fails most often. It covers unknown or other.
Recall coverage here is not complete, and complaints are owners’ unverified reports (how this record is built). Check a specific VIN at NHTSA before you buy. Full tables are on the Reign, Hampton & Sprout line page.