01 What makes it unique
KZ lists the 2026 Sportster X 3915X at 14,550 lb dry, a GVWR of 20,000 lb, a net carrying capacity of 5,450 lb and a pin weight of 3,100 lb. Its dry weight plus its carrying capacity comes to exactly its GVWR.
It is 44' 5" long and 13' 5" high. KZ prints its tanks as 100 gal fresh, 50 gal grey, 90 gal black.
Every number on this page was read on 8 Nov 2026 from KZ’s own 2026 Sportster X floorplan page for the Sportster X 3915X, whose heading names the model year 2026.
02 Full specifications
Dimensions
- Exterior length
- 44' 5"
- Exterior height
- 13' 5"
- Exterior width
- 100"
- Interior height
- 102"
Weights
- Dry / unit base weight (UVW)
- 14,550 lb
- GVWR (max loaded)
- 20,000 lb
- Net cargo / payload (CCC)
- 5,450 lb
- Hitch / pin weight
- 3,100 lb
Capacities
- Fresh water
- 100 gal
- Grey water
- 50 gal
- Black water
- 90 gal
Running gear
- Hitch type
- Fifth wheel (pin box)
- Tire size
- 16"
Sleeping & layout
- Sleeps
- 7
- Availability (as printed)
- KZ files this floorplan “Dealer Stock Only”: sold from dealer inventory, not orderable from the factory
- Model year (as printed)
- floorplan drawing labelled “2026 KZ RV Sportster X 3915X Fifth Wheel Toy Hauler Floorplan” on KZ’s page
- Awning
- 15'/15'
How these published figures sit against the rest of the catalogue: fifth wheel pin weight and payload; fresh, grey and black tank sizes; camper trailer size chart.
Drawn to scale
Weight budget
Size, with end view
Holding tanks
Axles, wheels and nose shape are schematic; not a floorplan. Data: dataset.
Towing it
Check your vehicle. Enter the ratings from your owner’s manual and the door-pillar placard.
Compares your figures with this page’s published GVWR (20,000 lb) and the upper loaded pin estimate (5,000 lb, a rule of thumb). Your vehicle’s placard and the trailer’s own weight label govern.
Loaded range: 15–25% of GVWR on the pin, a rule of thumb, not a measurement of this unit. No truck ratings or hitch classes (why; NHTSA, DOT HS 809 433). The range starts at the published figure, because loaded is never lighter than that.
03 The Sportster X floorplan family
The Sportster X floorplan below was added from KZ’s 2026 Sportster X floorplan page; every Sportster X floorplan on this site, every model year, is listed on the Sportster X hub.
| Floorplan | Nominal | Sleeps |
|---|---|---|
| Sportster X 3915X | 44' 5" | 7 |
The Sportster X floorplan below was added from KZ’s 2026 Sportster X floorplan page; every Sportster X floorplan on this site, every model year, is listed on the Sportster X hub.
04 Notes on this floorplan
What KZ does not publish for the Sportster X 3915X
Nothing is filled from a sibling model, a different model year or a dealer listing.
Read the label on the trailer
The weight label every RV trailer carries by law (49 CFR 571.110 and 571.120) governs the towing decision, not this page.
05 How it compares
06 Loading it for a trip
A full 100-gallon fresh tank is about 830 lb of water (water counts as cargo: 49 CFR 571.120 S10.4.2), 15% of the Sportster X 3915X’s 5,450 lb cargo capacity, leaving 4,620 lb (660 lb per rated berth). Your own unit’s figure is on the label inside its entry door (49 CFR 571.120 S10.4.3).
07 Where this floorplan sits
| Other lines, nearest by GVWR | GVWR (lb) | Dry (lb) | Sleeps | Length |
|---|---|---|---|---|
| Sportster X 3915X | 20,000 | 14,550 | 7 | 44 ft 5 in |
| Seismic 4213 | 20,000 | 15,385 | 8 | 43 ft 5 in |
| Model Gx 3500x | 19,250 | 15,600 | — | 40 ft 2 in |
| Riverstone 38BMB | 19,250 | 17,186 | — | 39 ft 7 in |
| Pinnacle 39DSDB | 19,200 | 16,360 | 8 | — |
| Ambition 399TH | 21,000 | 16,900 | — | 43 ft 7 in |
| Cyclone 3913 | 21,000 | 15,435 | 8 | 46 ft 5 in |
Against the Sportster X 3915X: the Seismic 4213 is 1 ft shorter and sleeps 1 more; the Model Gx 3500x is 750 lb lighter and 4 ft shorter; the Riverstone 38BMB is 750 lb lighter and 5 ft shorter.
08 Common questions about the Sportster X 3915X
How much does the Sportster X 3915X weigh?
14,550 lb dry; 20,000 lb GVWR, the most it may weigh loaded.
How much can the Sportster X 3915X carry?
5,450 lb, 27% of its GVWR (median across 491 fifth wheels here: 19%). A full fresh tank uses 830 lb of it.
What is the pin weight of the Sportster X 3915X?
3,100 lb as published, 21% of the dry weight (median across 727 fifth wheels here: 19%).
What size tow vehicle does the Sportster X 3915X need?
A tow rating of at least 20,000 lb, plus payload for the loaded pin weight, passengers and cargo.
How many people does the Sportster X 3915X sleep?
It is rated to sleep 7.
What are the tank capacities on the Sportster X 3915X?
Fresh 100, grey 50, black 90 gallons. Off hookups, fresh water runs out first.
How long is the Sportster X 3915X?
44' 5" overall, tongue or pin box included.
From the figures above.
09 What this page publishes, and what it does not
13 of the 18 fields this catalogue tracks are published for the Sportster X 3915X. Not published: slide count, axle count, refrigerator, air conditioning, tire size (a description is published, a size is not).
Sourcing rules: methodology.
10 Manuals & documents
Sources: kz-rv.com (linked below); the full source note is at the foot of the page.
11 NHTSA safety record
No recall campaign or owner complaint in our NHTSA data names the Sportster X line. Read that as no result found, not as a clean record.
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 Sportster X line page.