2026 Keystone RV Montana 3900RK

2026 Keystone RV Montana 3900RK

North America's #1 Selling Fifth Wheel
Montana has earned its reputation the hard way. Not on a showroom floor, but out on the road. Built by experienced craftsmen and shaped by owners who put real miles behind every decision, Montana is designed around how people actually live and travel. That work shows up in the details. A better warranty, backed by an industry-leading five-year structural commitment. A better ride. Smarter storage. A master suite designed for real time on the road. And an overall experience built to hold up season after season, supported by better materials, a stronger foundation, and customer support that stays with you. Montana. Proven by the People.

SolarFlex RV Solar

Take Charge of How You Camp

Incredibly versatile and expertly designed, SolarFlex™ is redefining factory-installed solar power, exceeding customer expectations. SolarFlex™ takes the guesswork out of the equation by offering affordable, high-quality RV solar energy systems. Each package is designed to grow with you, allowing owners to easily expand their system with approved, warrantied parts available exclusively through authorized Keystone dealers. To further enhance performance, all SolarFlex™ packages can be upgraded with cutting-edge Dragonfly Energy Lithium-ion batteries—available as a factory-installed option or as an aftermarket upgrade through your dealer.

SCROLL TO THE BOTTOM OF THE PAGE FOR SOLARFLEX MANUALS, QUICK START & TROUBLESHOOTING GUIDES.

Security

Intelligently engineered by the experts at the Keystone Innovation Lab. SolarFlex uses best-in-class hardware and configuration options designed specifically for RVers. Fully integrated during the build process, SolarFlex eliminates the patchwork of an aftermarket build and is covered by Keystone’s fully transferable warranties.

Control

Monitor and optimize your solar energy in real-time using the Victron app. 

Protection

Every RV owner knows the sinking feeling of a dead battery. SolarFlex can provide continuous charge, ensuring the operation of 12V systems and avoiding battery depletion and replacement.  

Flexibility

SolarFlex offers four distinctive packages delivering different levels of solar energy. Each package is designed to grow with you—offering easy add-ons for more power collection and storage.  

Titan Leveling System

Advanced Hydraulic Leveling

Now Available on Most Keystone Fifth Wheels

With an updated control system with a touch screen and a single sensor for leveling, this brand-new low-profile hydraulic leveling system is now available on several of our fifth wheel brands. The Titan system cuts 1/3rd of the weight from the competition and provides you with high-impact lighting for those early morning or late night travel days.

High Impact Lighting

Great for early morning and late night travel days, you can easily see and make sure that the ground is clear.

Low Profile Footpad

Better traction with the refined low profile footpad design.

Touch Screen Control System

You can easily operate this system with the click of a button. This system can also be run off of the OneControl app.

Four Season Camping

Water lines and tanks protected to keep you camping down to 0°F

Innovation Leadership

These models feature exclusive ground-breaking components and technologies from the Keystone Inovation Lab.

A Better Fifth Wheel Chassis

VIDEO HIGHLIGHTS

Rolled 1-piece I-beams eliminate potential welded failure points

Full-width outriggers fully support sidewall weight

Lighter stamped steel crossmembers replace welded rod-and-angle construction

Rotocast 1-piece tanks eliminate seamed and glued failure points

Steel straps prevent tanks from billowing in transit and impinging on the floor

Patented MaxTurn™ bent-tube frame design increases turning radius without welds

Blade Pure™ Airflow System

20% MORE COOLING POWER + AIR FILTRATION AND SOUND DAMPENING

A thoughtful combination of new-age efficiency and residential comfort, Blade Pure takes camping comfort to the next level. Now available on Alpine, Avalanche, Arcadia, Cougar, Montana, Montana High Country, & Sprinter.

MERV 9 Filtration

Tested to remove up to 50% of 1-3 micron particles for cleaner, healthier air. Blade Pure removes contaminants such as dust, mites, pet dander, pollen, mold, and auto fumes providing an extra layer of safety and peace of mind.  According to the EPA, indoor air can contain 2-5 times the amount of pollutants found outdoors, Blade Pure ensures those suffering from asthma and allergies get to breathe easier while traveling the country or weekending at their local campground (Indoor Air Quality, 2018).

The Quiet Series

The Coleman-Mach Q Series is undoubtedly the quietest air conditioner in the industry. With a combined noise reduction of more than 10-15 decibels over traditional A/C's without filtration, campers will enjoy movie nights, conversations, and better sleep without the distraction of a loud air conditioning unit. 

12V Color-Coded Wiring Standard

SMART & SIMPLE

Learn how Keystone’s EXCLUSIVE color-coded 12V wiring is different from conventional RV wiring and why it’s a better for both owners and service technicians.

Easy-to-trace circuits help dealer service techs troubleshoot and complete repairs more quickly, saving owner’s time and money.

Clearly labeled wiring helps savvy owners with DIY diagnosis and repair of technical issues.

Tru-Fit™ Slide Construction 

A BETTER FOUNDATION

A long-time RV owner recently stood in our office and pronounced that auto-leveling and slide rooms were the industry's two greatest inventions, and we have to agree. As great as slide rooms are, it's important to remember that they aren't all created equal.

When shopping for a new RV, look for slides that are well-engineered and well-built to both keep water out and stand up to the mechanical stresses of moving hundreds of pounds in and out of your coach.

The Innovation Lab's Tru-Fit™ Slide contruction tackles durability and weather protection head on.

With custom-engineered frames for every floorplan, Keystone RV eliminates the compromises other manufacturers are forced to make as they try to adapt new floorplan designs to work with stock frames. Keystone's Tru-Fit frame design optimizes each slide's position to reduce stress on the structure and motor, resulting in a more durable build and consistent performance. A flexible rubber seal is added to both the slide-out structure and the side wall, doubling the RV's protection against the elements.

The result? More durable and weather-resistant slide rooms that are most definitely built for the long haul.

4G LTE and WiFi Prep

Keystone RV Company now offers 4G LTE and WiFi prep on every model we manufacture. Our engineering and sourcing teams have developed a solution that makes it simple, easy and affordable for owners to add WiFi or cellular connectivity to your coach.

Winegard AIR 360+ Omni-Directional Rooftop Antenna
Eliminates dead spots

Every Keystone RV includes the Air 360+ antenna with wiring connecting it to a receiver plate for easy intallation of a WiFi router. This antenna receives AM, FM and over-the-air television signals, and is HDTV compatible. It also features dual 4G antennae to optimize reception, two times the signal strength, and a built-in gain low noise amplifier to minimize interference.

Winegard Gateway 4G LTE WiFi Router
Prepped and ready for installation

Stay connected while parked or while traveling. Your system is designed to work with the Winegard Gateway 4G LTE WiFi Router (GW-1000, MSRP $299). This router clicks seemlessly into place on the pre-installed wall plate and activates the 4G LTE antennae in the Air 360+. The Winegard Gateway supports HD streaming with 150 Mbps max and 4G LTE download, amplifies park WiFi, distributes you WiFi signal for up to a half mile, and offers WPA, WPA2 and WPA mixed wireless security.

Features May Include: 

Exterior

• 12" I-beam w/ z-frame technology
• Helux Pin Box
• 2" thick composite backed high gloss fiberglass sidewalls and insulated rear wall
• 4k Square Frameless tinted safety glass windows
• Fiberglass front cap w/ KeyShield™ automotive-grade paint
• Fully walkable roof w/ Alpha seamless TPO membrane system and 5" rafters
• Rear ladder
• Hydraulic slideouts on main level w/ individual switches & electric slideouts on upper deck
• Insulated underbelly w/ forced hot air & electric tank heaters
• Curt TCS (Touring Coil Spring) 8K Axles
• Curt ABS (Anti-Lock Braking System)
• 17.5" Wheels
• H-Rated Tires
• TPMS Prep
• 6' 6" tall 30" wide entry door w/ screen & friction hinge
• 4 Step entry steps w/ strut assist
• Large pass through storage w/ oversized slam latch door
• Premium oversized steel slide out storage tray
• Slide Out rear Gear Storage Trays.
• Back-up camera prep
• 2nd battery disconnect dedicated to residential refrigerator (inverter models)
• Dual battery boxes
• Water connections, black tank flush, outside shower w/ quick connect hose, winterization kit, water heater bypass, power tank fill, waste & water handle valves, 110V outlet, shutoff valve, 12V compartment light, enclosed low point drains, intuitive KeyTV™ satellite/cable/ antennae source control
• Seamless roto-cast holding tanks
• 50 Amp Power Cord Reel
• Outside shower w/ quick disconnect hose
• Lippert 12V electric patio awning(s) w/ LED lights
• 2nd Lippert 12V electric patio awning(s) w/ LED lights
• 3000 lb towing hitch
• MORryde® Safe-T-Rail door handle
• Lippert Titan™ leveling system w/ touch screen and underlights
• 12V distribution Giggy Box™
• Electric power cord reel
• Electric Dump Valves

Interior

• Hardwood decorative slideout fascia
• Reflective window shades built into window
• Hardwood decorative window frames
• Hardwood cabinetry, stiles, & framing
• Decorative backlit crown molding in living area, hardwood base molding in hallway and living area
• 5K BTU decorative fireplace heater in Bedroom and Living Room
• SBC V-Flow Max Cordless Vacuum

Keystone Exclusives

• 5-year limited structural warranty
• 1-year limited base warranty
• Color-coded unified wiring standard
• 4G LTE and Wi-Fi prep
• Tuf-Lok™ thermoplastic duct joiners
• KeyTV™ multisource signal controller
• Tru-fit™ slide construction
• Blade Pure™

Kitchen Features

• Full extension ball bearing drawer glides, hidden cabinet hinges
• Solid Surface Backsplash
• Solid surface kitchen countertops
• Solid Surface waterfall island
• Oversized deep stainless steel sink with attachments
• High-rise pull down faucet
• Adjustable Sliding "Deskette" w/ 4 chairs
• Flush floor slideout(s)

Appliances & Utilities

• (2) 40 lb LP tanks w/ auto changeover
• 18K Furrion Chill Cube Main A/C with heat pump
• 13.5 K Furrion AC for 2nd and 3rd ACs
• Starlink Prep
• 35K BTU furnace
• 60K BTU Suburban On Demand Water Heater
• 55" 4K Smart TV and JBL 2.1 Soundbar and Subwoofer
• 20 Cu. Ft. 12V refrigerator
• Residential size stainless steel convection microwave
• 24" Furrion freestanding 4-burner range with 3.7 Cu Ft Oven
• Stackable washer/dryer prep
• Pendant style island light w/ ceiling treatment

Bedroom Features

• King size bed
• Adjustable reading lights
• USB & 110V outlets bedside
• Foam mattress & decorative bedspread/pillow package
• 40" 4K SMART TV in Bedroom
• Built IN jewelry center with hamper

Bathroom Features

• Decorative vanity w/ stainless sink
• Residential 30" X 48" fiberglass shower w/ decorative glass enclosure, skylight, & molded accessory/foot shelf
• Porcelain foot flush toilet
• Bathroom power vent fan w/ rain sensor

Weather Protection

• Four Season Living Package
• 12V heat pads on holding tanks
• Astrofoil insulated slide floors & underbelly
• Dual attic vents
• Heated and enclosed underbelly, convenience center, & dump valves
• Reflective foil insulated front cap
• Tested and approved for 0° usage

Safety

• Breakaway switch
• GFI receptacles
• CO detector
• Smoke detector
• Propane gas leak detector
• Fire extinguisher

Options: 

Exterior

• Dual pane frameless windows w/ safety tint
• Generator prep
• RVMP Flex Power 5500 Generator
• Slide-out awning package
• MORryde® Independent Suspension System
• Frontier Gold full body paint
• Furrion Vision S side & rear observation system

Appliances & Utilities

• 18 Cu. Ft. residential refrigerator w/ 2000w inverter

Bedroom Features

• 60" x 80" full size queen bed