2026 Forest River Sierra4002FB

The Sierra 4002FB has 2,611 lbs of cargo capacity between 12,889 lbs dry and its 15,500 lbs GVWR, 17% of that rating; filling its 50-gallon fresh tank at 8.3 lb a gallon uses 415 lbs of it (how to read trailer weights).

Pin weight is 2,340 lbs, 18% of the dry weight as published; it rises as the trailer is loaded and comes off the truck’s payload, not its towing rating, so check it against the payload on your own door sticker (pin weight and payload).

Off hookups: 200 gallons of grey and black capacity against 50 gallons of fresh water, so fresh water runs out first (tank sizes by length).

Against the rest of the Sierra roster this is the 7th of 9 floorplans by dry weight, in a line that runs from 10,869 lbs to 13,864 lbs. It sits in the heavier third of the line.

Plan the tow on loaded weight, not the 12,889 lbs dry figure: half the published cargo capacity brings this plan to about 14,195 lbs, and the published GVWR of 15,500 lbs is the limit (how to read trailer weights).

Forest River’s line listing and this floorplan’s own factory page agree on all 4 shared figures. Dry weight plus cargo capacity equals the published GVWR exactly. A missing row means Forest River does not publish that figure (how figures are verified).

Forest River's own description of this floorplan reads: “The 4002FB is a double queen bed and loft coach. With 4 slideouts and a double bunk loft, this floorplan has enough sleeping space for whoever wants to tag along. Rear entry into the 2nd full bath will offer full amenities without cluttering or using the master bath. The island kitchen and theater seating provide a great space to entertain and unwind. The 4002FB is extremely versatile, utilizing the extra bedroom or…” That is the factory's marketing copy rather than a specification, and nothing in it is treated as a verified field on this page - layout descriptions, sleeping arrangements and feature claims in factory copy are not carried into the spec table unless the factory also publishes them as specifications.

How the 4002FB differs from the other eight Sierra floorplans. Most distinctive first. Sibling pages may cover other model years than this one (2026). How these ranks are worked out.

• Cargo capacity, 2,611 lb: second-smallest of nine, between the 3844QUAD (2,431 lb) and the 3800RK (2,651 lb).
• Cargo capacity as a share of GVWR, 16.8%: second-smallest of nine, between the 3844QUAD (14.9%) and the 3800RK (17.1%).
• Dry weight, 12,889 lb: third-heaviest of nine, between the 3800RK (12,849 lb) and the 3900HBLR (13,284 lb).
• Length, 43 ft 5 in: third-longest of nine, between the 3710HBFB, 3844QUAD and two others (42 ft 9 in) and the 3990FL (43 ft 6 in).
• Black tank, 100 gal: third-largest of nine, between the 3844QUAD (82 gal) and the 3710HBFB and 3900HBLR (104 gal).
• Pin weight, 2,340 lb: fourth-heaviest of nine, between the 3844QUAD (2,295 lb) and the 3710HBFB and 3800RK (2,405 lb).
• Pin weight as a share of dry weight, 18.2%: fifth-smallest of nine, between the 3480RL (17.1%) and the 3800RK (18.7%).
• Grey tank, 100 gal: shared with the 3800RK and 4003MB; of nine, one smaller and five larger, nearest the 3990FL (80 gal) and the 3100RD, 3480RL and two others (104 gal).
• GVWR, 15,500 lb: shared with the 3710HBFB, 3800RK and 4003MB; of nine, three lower and two higher, nearest the 3990FL (15,375 lb) and the 3900HBLR (16,085 lb).

Next to the 3800RK, the nearest lighter floorplan by dry weight, the 4002FB is 40 lb heavier by dry weight, has 40 lb less cargo capacity, has a pin weight 65 lb lighter, is 8 in shorter and has a black tank 50 gal larger; the two publish the same GVWR, exterior height, fresh tank and grey tank.

Next to the 3900HBLR, the nearest heavier floorplan by dry weight, the 4002FB is 395 lb lighter by dry weight, has a GVWR 585 lb lower, has 190 lb less cargo capacity, has a pin weight 255 lb heavier, is 8 in longer, has a grey tank 36 gal smaller and has a black tank 4 gal smaller; the two publish the same exterior height and fresh tank.

Sierra's published pin weights spread further than its dry weights do, and that is the fact worth carrying into a dealership: nine floorplans run 10,319 to 13,864 lb dry - a 3,500 lb band - while pin weight runs 1,560 to 2,825 lb, nearly doubling. Two Sierras a thousand pounds apart on the scale can be far apart at the pin too. Every plan on the roster ties out exactly against its published GVWR.

A full 50-gallon fresh tank is about 415 lb of water (water counts as cargo: 49 CFR 571.120 S10.4.2), 16% of the 4002FB’s 2,611 lb cargo capacity, leaving 2,196 lb. Across 9 Sierra floorplans the water share runs 14% to 19%, and 3 give up more than this one. Nearest on that share: Sierra 3800RK at 16% and Sierra 3844QUAD at 17%. Your own unit’s figure is on the label inside its entry door (49 CFR 571.120 S10.4.3).