2021 Sierra by Forest River M-401FLX Specs

Specifications

Floor Plan

Type

Destination

Basic Warranty (Months)

Revision Status

Carryover

Maximum Sleeping Capacity

Number Of Slideouts

Length (ft-in / m)

42' 4' / 12.9

Interior Height (in / mm)

99 / 2514.6

Base Weight (lbs / kg)

10830 / 4912.5

Carrying Capacity (lbs / kg)

3011 / 1365.8

Hitch Weight (lbs / kg)

1841 / 835.1

Number Of Axles

Air Conditioning (BTUs)

15000

Heater (BTUs)

40000

Fresh Water Capacity (gal / L)

50 / 189.3

Gray Water Capacity (gal / L)

156 / 590.5

Black Water Capacity (gal / L)

52 / 196.8

Propane Capacity (gal / lbs)

14.2 / 60

Water Heater Tank (gal / L)

10 / 37.9

Air Conditioning

Standard

Kitchen Dinette

Chairs

Interior Flooring Type

Carpet / Vinyl

Master Bedroom

Standard

Number Of Bathrooms

Shower

Standard

Television

Standard

DVD Player

Standard

Patio Awning

Standard

Leveling Jack Type

Front Manual / Rear Manual

Power Retractable Entry Steps

Not Available

Interested in Selling Your Vehicle?

Get a verified offer sent directly to you.

Click Here

Make sure you're protected! Insure your RV for as low as just $125/year.*

JD Power Travel Trailer/5th Wheel Buying Program

Take advantage of real dealer pricing and shop special offers on new and used Travel Trailers/5th Wheels. Select your Travel Trailer/5th Wheel to get started.

Condition

Zip

See Dealer Pricing

Learn More about the JD Power Travel Trailer/5th Wheel Buying Program

Progressive RV Insurance

Insure your 2021 Sierra by Forest River M-401FLX for just $125/year*.

Leader in RV Insurance: Personalize your policy without breaking the bank.
Savings: We offer low rates and plenty of discounts.
Coverages: Specialized options for full timers and recreational RVers.

Get a Quote

*Annual premium for a basic liability not available in all states.

Other Resources

Use these tools provided by our trusted partners to complete your RV shopping experience.

Attention West Coast RV Owners

We’ll pay CASH for your RV — TODAY!

Get Cash

Sell Your Travel Trailers/5th Wheel with GoRollick

Receive a direct offer on your Travel Trailers/5th Wheel with GoRollick.

Get Started

Trucks and SUVs for Hauling

See All Trucks

See All SUVs

2025 Chevrolet Silverado 1500

9,100 lbs towing capacity

Starting at $37,000

Build and Price

2026 Jeep Gladiator

4,500 lbs towing capacity

Starting at $39,820

Best car deal in 43215

Build and Price

Research Other Trucks and Cars

Make

Model

Year

Research Another Vehicle

Truck Deals, Pricing and Values

2021 Sierra by Forest River M-401FLX Specs

Values

Specifications

Notes

Identification

Identification

Type

Basic Warranty (Months)

Revision Status

Specifications

Specifications

Maximum Sleeping Capacity

Number Of Slideouts

Length (ft-in / m)

Interior Height (in / mm)

Base Weight (lbs / kg)

Carrying Capacity (lbs / kg)

Hitch Weight (lbs / kg)

Number Of Axles

Air Conditioning (BTUs)

Heater (BTUs)

Holding Tanks

Holding Tanks

Fresh Water Capacity (gal / L)

Gray Water Capacity (gal / L)

Black Water Capacity (gal / L)

Propane Capacity (gal / lbs)

Water Heater Tank (gal / L)

Interior Features

Interior Features

Air Conditioning

Kitchen Dinette

Interior Flooring Type

Master Bedroom

Number Of Bathrooms

Shower

Television

DVD Player

Exterior Features

Exterior Features

Patio Awning

Leveling Jack Type

Power Retractable Entry Steps

Interested in Selling Your Vehicle?

JD Power Travel Trailer/5th Wheel Buying Program

Progressive RV Insurance

Other Resources

Attention West Coast RV Owners

Sell Your Travel Trailers/5th Wheel with GoRollick

Trucks and SUVs for Hauling

Research Other Trucks and Cars

Popular on JD Power

Popular RV Values

Popular RV Makes

Popular RV Specs

Popular RV Categories