M3i Indoor Bike
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We Built The Ultimate Indoor Bike

More than 20 years ago, Keiser set out to create a bike that would exceed the demands of indoor group cycling.

  • A bike that fits riders of all body shapes and sizes
  • A bike that achieves a quiet – but true – road-bike experience inside your gym or home
  • The ONLY bike built in the U.S. to ensure the tightest quality control
  • And the ONLY bike built entirely around YOU the rider, YOU the gym owner and YOU the service technician

…and we accomplished it all with the simplest of engineering design. Here’s how.

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Many indoor group cycling bike manufacturers claim a road-bike experience, but don’t get what’s important about road bikes: Frames that vary to accommodate riders of different sizes. We do.

Scroll to continue
FIRST TO ENGINEER A V-SHAPE FRAME

Our groundbreaking design mimics different bike frames by enabling the M3i seat and handlebars to be raised in conjunction with one another, fitting longer legs, torsos and arms.

BUILT FOR RIDERS BIG & SMALL

The M3i matches riders from 4’10” to 7’ tall (1,1473 mm to 2,233 mm) with a weight capacity of 350 pounds (159 kg), making it ideal for diverse group cycling classes.

Other indoor bikes mistakenly place the rider’s sweat zone directly over the flywheel and other vulnerable mechanisms – an obvious engineering flaw.

FIRST TO PUT THE FLYWHEEL AT THE REAR OF A BIKE

The M3i is more reliable, easier to clean and better protected from sweat and corrosion.

ANGLED CHANNEL FLOWS SWEAT AWAY FROM DRIVE-TRAIN

Superior sweat protection helps gym owners save money through lower maintenance costs and a longer bike life.

It’s easy to “claim” accuracy. Keiser guarantees it. As the FIRST to use magnetic resistance, we revolutionized indoor cycling by delivering a quiet, reliable ride with immediate accurate data for EVERY M3i bike.

RELENTLESS QUALITY CONTROL

EVERY COMPONENT of our axle assembly – the core piece responsible for predicting and delivering accurate ride data EVERY TIME – is inspected to meet precise tolerances. And EVERY DAY an M3i production bike is randomly dyno-tested to ensure quality and accuracy.

TRUE POWER READINGS

The M3i is the FIRST indoor bike to receive the globally recognized TÜV EN957-10 certification for accuracy and safety. Most competitors’ bikes are not certified by TÜV.

IMMEDIATE RIDE DATA

The M3i is the FIRST indoor bike designed to predict the power generated at any speed in any gear – ensuring that accurate ride data is always delivered immediately.

The competition endorsed Keiser’s engineering by following our lead on using magnetic resistance – but they should have also copied our drive-train design.

The simple M3i drive-train – with just a single Poly-V belt – produces the higher speeds necessary for a lighter-weight aluminum flywheel to provide the kinetic energy and magnetic resistance to simulate a good road-bike experience.

Our competitors’ outdated drive-trains must use a heavier, perimeter-weighted flywheel to accomplish the same. They actually brag about that, as well as cog-belt drives and crank-arm-to-flywheel ratios. But what they’re really telling you is…

THEY DESIGNED THEIR BIKE WRONG.
A QUIET AND SMOOTH RIDE

Our Poly-V belt design transmits very high loads over very small pulleys, achieving a good road-bike experience without a perimeter-weighted flywheel, a more complicated drive-train and the noise and vibration of a cog belt.

NO ADJUSTMENTS OR MAINTENANCE

The belt’s pre-tension design requires no adjustments, and the drive-train requires no maintenance other than routine inspection.

THE POLY-V BELT IS THE CHOICE OF AUTOMOTIVE MANUFACTURERS

The M3i uses the belt that’s the preferred choice to run the accessories on the front of car engines, because it’s so quiet, durable and reliable.

Many manufacturers talk about the distance between their indoor bike’s pedals, and boast about the narrow Q Factor. But their bikes were built around the narrow shoes and pelvises of elite cyclists, even though footwear and people of all sizes can be found in group cycling classes.

WHY WOULDN’T YOU DESIGN A BIKE TO FIT EVERYONE?
CURVED CRANK ARMS TO FIT WIDER HIPS AND BULKY SHOES

Instead of using straight crank arms to achieve a narrow Q Factor, Keiser recognized the need for versatility.

We added curvature to the M3i crank arms to maintain the proper distance for wider hips and any type of footwear, from narrow bike shoes to bulkier gym shoes.

Engineered beyond consumer standards for group classes, it’s more than a pedal – it’s a game changer, providing superior comfort, safety and durability.

DESIGNED FOR SPD RIDERS

Our M Series pedal ensures that the toe cage remains parallel to the ground and clear of the floor surface.

To meet the needs of riders, gym owners and maintenance technicians, we thought of everything when designing the Keiser digital system.

FIRST COMPUTER TO SHOW POWER OUTPUT

The M3i digital display is simple, with everything a rider needs to know on a single screen.

BACK-LIT DISPLAY

Automatically turns on when the room light drops below a set level and remains on, unlike other bikes.

NO BUTTONS

Eliminating inconvenience and a cause of wear and maintenance.

TRACK EVERY RIDE

The FIRST bike to offer Bluetooth® with open API, the M3i communicates with class projection systems while simultaneously syncing data to cycling apps.

RECORD EVERY DETAIL

Our M Series App easily logs every detail of your ride so you can see your progress.

MANAGE EVERY CLASS

Our M Series Instructor App shows live data from multiple bikes allowing instructors to make real-time class adjustments.

ENHANCE YOUR INDOOR CYCLING INSTRUCTION WITH FTP TESTING, DYNAMIC TRAINING & MORE

With the Keiser M Series Group app featuring Functional Threshold Power (FTP) Training, indoor cycling instructors can enhance their teaching capabilities to easily transform classes into fun and fiery competitions that inspire riders and keep them coming back for more.

TAP INTO A WIDE VARIETY OF TRAINING OPTIONS

Use Distance, Energy and Cadence for performance monitoring, and the app doesn’t lock you into any one type of class. Other group class apps simply don’t offer such a wide variety of training options.

FEATURES OFFERED BY THE APP INCLUDE:

  • Unranked Rides
  • FTP Testing
  • Intervals (Timed Sets)
  • Team Challenges
  • Class Summaries

M3i with clickable hotspots
Media Tray Handlebars Shifter Easy Adjustment Easy Adjustment Water Bottle Holder Simplified Maintenance Easy Transport Leveler Stretch Pad

The M3i features a wide array of details, benefits and features, offering additional fit and comfort, enhanced durability and simplified upkeep.

Click to discover the details
Media Tray Handlebars Shifter Easy Adjustment Easy Adjustment Water Bottle Holder Simplified Maintenance Easy Transport Leveler Stretch Pad
SIMPLIFIED MAINTENANCE

M3i drive-train can be accessed by removing just eight Phillips head screws vs. over three times more on some competitors’ bikes.

Media Tray Handlebars Shifter Easy Adjustment Easy Adjustment Water Bottle Holder Simplified Maintenance Easy Transport Leveler Stretch Pad
STANDARD MEDIA TRAY

For holding cell phones and tablets.

Media Tray Handlebars Shifter Easy Adjustment Easy Adjustment Water Bottle Holder Simplified Maintenance Easy Transport Leveler Stretch Pad
EASY ACCESS TO SHIFTER

Mounted directly to handlebars for ease of use and increased safety, especially when riding out of the saddle. Interval training is activated by simply pushing the shifter all the way down and back up, making it ideal for HIIT workouts.

Media Tray Handlebars Shifter Easy Adjustment Easy Adjustment Water Bottle Holder Simplified Maintenance Easy Transport Leveler Stretch Pad
WATER BOTTLE HOLDER

Incorporated into frame design and fits both small and large sizes.

Media Tray Handlebars Shifter Easy Adjustment Easy Adjustment Water Bottle Holder Simplified Maintenance Easy Transport Leveler Stretch Pad
WIDE ARRAY OF HAND POSITIONS

Continuous design of handlebars provides multiple hand positions for indoor cycling.

Media Tray Handlebars Shifter Easy Adjustment Easy Adjustment Water Bottle Holder Simplified Maintenance Easy Transport Leveler Stretch Pad
EASY-TO-ADJUST SEAT AND HANDLEBARS

Quick, intuitive vertical and horizontal adjustments of seat and handlebars, as well as robust knobs requiring less maintenance than a traditional cam-lock.

Media Tray Handlebars Shifter Easy Adjustment Easy Adjustment Water Bottle Holder Simplified Maintenance Easy Transport Leveler Stretch Pad
STRETCH PAD

Located on bike base to facilitate pre- and post-ride stretching.

Media Tray Handlebars Shifter Easy Adjustment Easy Adjustment Water Bottle Holder Simplified Maintenance Easy Transport Leveler Stretch Pad
LEVELER

The leveler foot can be adjusted by slightly lifting the appropriate corner of the bike and screwing the foot clockwise or counter-clockwise.

Media Tray Handlebars Shifter Easy Adjustment Easy Adjustment Water Bottle Holder Simplified Maintenance Easy Transport Leveler Stretch Pad
EASY TO TRANSPORT

Fewer parts and a lighter flywheel for ease of transport.

The Ultimate Machine for Indoor Group Cycling

With more than a quarter million of our M Series sold worldwide and countless reviews placing in at the top of the industry, it’s easy to see why there is no indoor group cycling bike on the planet more proven than the M3i.

  • Amazon.com (135+ reviews)
  • The Ferrari of spin cycles.
    GarageGymBuilder.com
  • A beast when it comes to spin bikes.
    BodyGearGuide.com
  • The design and appeal of the Keiser
    M3i is worth the cost.
    Top Fitness Magazine
Shop for Home See more reviews
COMPATIBLE
WITH VIRTUALLY
ANY TRAINING APP OR VIDEO
COMPETE AGAINST YOURSELF OR OTHERS
AT HOME OR AT THE CLUB/GYM

Optimize your ride at home or health club. You choose an app. Keiser gets you connected. Enhance your workouts with endless app possibilities for the ultimate cycling experience.

COMPATIBLE WITH ALL
MAJOR PROJECTION SYSTEMS

As the industry’s FIRST company-designed projection system, Keiser eliminates any need for gym owners to work with separate bike and projection suppliers. But in true Keiser fashion, the M3i receiver is also compatible with all major projection system providers, giving gym owners a wide array of options.

Take classes to the next level

In person – and online – Keiser’s world-renowned Master Trainers offer the lessons, skills and tools so instructors can train clients the right way and keep them coming back for more.

BECOME A CERTIFIED KEISER INSTRUCTOR

Foundations in an on-site, eight-hour course during which a Keiser Master Trainer teaches and applies all of the required information attendees need to become a Keiser indoor group cycling class instructor.

DOWNLOAD THE M SERIES INSTRUCTOR APP

View live data from multiple bikes on one device and make class adjustments in real time with the free M Series Instructor App for Apple® or Android™ devices.

LEARN MORE about Keiser PowerED

Instructor application and app screenshots
Keiser Videos

More than 20 years ago, Keiser set out to create a bike that would exceed the demands of indoor group cycling.

  • A bike that fits riders of all body shapes and sizes
  • A bike that achieves a quiet – but true – road-bike experience inside your gym or home
  • The ONLY bike built in the U.S. to ensure the tightest quality control
  • And the ONLY bike built entirely around YOU the rider, YOU the gym owner and YOU the service technician

…and we accomplished it all with the simplest of engineering design.

Here’s How we did it

Many indoor group cycling bike manufacturers claim a road-bike experience, but don’t get what’s important about road bikes: Frames that vary to accommodate riders of different sizes. We do.

FIRST TO ENGINEER A V-SHAPE FRAME

Our groundbreaking design mimics different bike frames by enabling the M3i seat and handlebars to be raised in conjunction with one another, fitting longer legs, torsos and arms.

BUILT FOR RIDERS BIG & SMALL

The M3i matches riders from 4’10” to 7’ tall (1,1473 mm to 2,233 mm) with a weight capacity of 350 pounds (159 kg), making it ideal for diverse group cycling classes.

Other indoor bikes mistakenly place the rider’s sweat zone directly over the flywheel and other vulnerable mechanisms – an obvious engineering flaw.

FIRST TO PUT THE FLYWHEEL AT THE REAR OF A BIKE

The M3i is more reliable, easier to clean and better protected from sweat and corrosion.

ANGLED CHANNEL FLOWS SWEAT AWAY FROM DRIVE-TRAIN

Superior sweat protection helps gym owners save money through lower maintenance costs and a longer bike life.

It’s easy to “claim” accuracy. Keiser guarantees it. As the FIRST to use magnetic resistance, we revolutionized indoor cycling by delivering a quiet, reliable ride with immediate accurate data for EVERY M3i bike.

RELENTLESS QUALITY CONTROL

EVERY COMPONENT of our axle assembly – the core piece responsible for predicting and delivering accurate ride data EVERY TIME – is inspected to meet precise tolerances. And EVERY DAY an M3i production bike is randomly dyno-tested to ensure quality and accuracy.

TRUE POWER READINGS

The M3i is the FIRST indoor bike to receive the globally recognized TÜV EN957-10 Certification for accuracy and safety. Most competitors’ bikes are not certified by T&‌Uuml;V.

IMMEDIATE RIDE DATA

The M3i is the FIRST indoor bike designed to predict the power generated at any speed in any gear – ensuring that accurate ride data is always delivered immediately.

The competition endorsed Keiser’s engineering by following our lead on using magnetic resistance – but they should have also copied our drive-train design.

The simple M3i drive-train – with just a single Poly-V belt – produces the higher speeds necessary for a lighter-weight aluminum flywheel to provide the kinetic energy and magnetic resistance to simulate a good road-bike experience.

Our competitors’ outdated drive-trains must use a heavier, perimeter-weighted flywheel to accomplish the same. They actually brag about that, as well as cog-belt drives and crank-arm-to-flywheel ratios. But what they’re really telling you is…

THEY DESIGNED THEIR BIKE WRONG.
A QUIET AND SMOOTH RIDE

Our Poly-V belt design transmits very high loads over very small pulleys, achieving a good road-bike experience without a perimeter-weighted flywheel, a more complicated drive-train and the noise and vibration of a cog belt.

NO ADJUSTMENTS OR MAINTENANCE

The belt’s pre-tension design requires no adjustments, and the drive-train requires no maintenance other than routine inspection.

THE POLY-V BELT IS THE CHOICE OF AUTOMOTIVE MANUFACTURERS

The M3i uses the belt that’s the preferred choice to run the accessories on the front of car engines, because it’s so quiet, durable and reliable.

Many manufacturers talk about the distance between their indoor bike’s pedals, and boast about the narrow Q Factor. But their bikes were built around the narrow shoes and pelvises of elite cyclists, even though footwear and people of all sizes can be found in group cycling classes.

WHY WOULDN’T YOU DESIGN A BIKE TO FIT EVERYONE?
CURVED CRANK ARMS TO FIT WIDER HIPS AND BULKY SHOES

Instead of using straight crank arms to achieve a narrow Q Factor, Keiser recognized the need for versatility.

We added curvature to the M3i crank arms to maintain the proper distance for wider hips and any type of footwear, from narrow bike shoes to bulkier gym shoes.

Engineered beyond consumer standards for group classes, it’s more than a pedal – it’s a game changer, providing superior comfort, safety and durability.

DESIGNED FOR SPD RIDERS

Our M Series pedal ensures that the toe cage remains parallel to the ground and clear of the floor surface.

To meet the needs of riders, gym owners and maintenance technicians, we thought of everything when designing the Keiser digital system.

FIRST COMPUTER TO SHOW POWER OUTPUT

The M3i digital display is simple, with everything a rider needs to know on a single screen.

BACK-LIT DISPLAY

Automatically turns on when the room light drops below a set level and remains on, unlike other bikes.

NO BUTTONS

Eliminating inconvenience and a cause of wear and maintenance.

TRACK EVERY RIDE

The FIRST bike to offer Bluetooth® with open API, the M3i communicates with class projection systems while simultaneously syncing data to cycling apps.

RECORD EVERY DETAIL

Our M Series App easily logs every detail of your ride so you can see your progress.

MANAGE EVERY CLASS

Our M Series Instructor App shows live data from multiple bikes allowing instructors to make real-time class adjustments.

ENHANCE YOUR INDOOR CYCLING INSTRUCTION WITH FTP TESTING, DYNAMIC TRAINING & MORE

With the Keiser M Series Group app featuring Functional Threshold Power (FTP) Training, indoor cycling instructors can enhance their teaching capabilities to easily transform classes into fun and fiery competitions that inspire riders and keep them coming back for more.

TAP INTO A WIDE VARIETY OF TRAINING OPTIONS

Use Distance, Energy and Cadence for performance monitoring, and the app doesn’t lock you into any one type of class. Other group class apps simply don’t offer such a wide variety of training options.

FEATURES OFFERED BY THE APP INCLUDE:

  • Unranked Rides
  • FTP Testing
  • Intervals (Timed Sets)
  • Team Challenges
  • Class Summaries

The M3i features a wide array of details, benefits and features, offering additional fit and comfort, enhanced durability and simplified upkeep.

SIMPLIFIED MAINTENANCE

M3i drive-train can be accessed by removing just eight Phillips head screws vs. over three times more on some competitors’ bikes.

STANDARD MEDIA TRAY

For holding cell phones and tablets.

EASY ACCESS TO SHIFTER

Mounted directly to handlebars for ease of use and increased safety, especially when riding out of the saddle. Interval training is activated by simply pushing the shifter all the way down and back up, making it ideal for HIIT workouts.

WATER BOTTLE HOLDER

Incorporated into frame design and fits both small and large sizes.

WIDE ARRAY OF HAND POSITIONS

Continuous design of handlebars provides multiple hand positions for indoor cycling.

EASY-TO-ADJUST SEAT AND HANDLEBARS

Quick, intuitive vertical and horizontal adjustments of seat and handlebars, as well as robust knobs requiring less maintenance than a traditional cam-lock.

STRETCH PAD

Located on bike base to facilitate pre- and post-ride stretching.

LEVELER

The leveler foot can be adjusted by slightly lifting the appropriate corner of the bike and screwing the foot clockwise or counter-clockwise.

EASY TO TRANSPORT

Fewer parts and a lighter flywheel for ease of transport.

Keiser’s commitment to constant innovation continues to lead the indoor cycling industry. With more than a quarter million of our M Series sold worldwide and countless reviews placing it at the top of the industry, it’s easy to see why there is no indoor group cycling bike on the planet more proven than the M3i — and the only bike built entirely around YOU.

  • Amazon.com (135+ reviews)
  • The Ferrari of spin cycles.
    GarageGymBuilder.com
  • A beast when it comes to spin bikes.
    BodyGearGuide.com
  • The design and appeal of the Keiser
    M3i is worth the cost.
    Top Fitness Magazine
COMPATIBLE WITH VIRTUALLY ANY TRAINING APP OR VIDEO
COMPETE AGAINST YOURSELF OR OTHERS AT HOME OR AT THE CLUB/GYM

Optimize your ride at home or health club. You choose an app. Keiser gets you connected. Enhance your workouts with endless app possibilities for the ultimate cycling experience.

COMPATIBLE WITH ALL MAJOR PROJECTION SYSTEMS

As the industry’s FIRST company-designed projection system, Keiser eliminates any need for gym owners to work with separate bike and projection suppliers. But in true Keiser fashion, the M3i receiver is also compatible with all major projection system providers, giving gym owners a wide array of options.

In person – and online – Keiser’s world-renowned Master Trainers offer the lessons, skills and tools so instructors can train clients the right way and keep them coming back for more.

Become a certified Keiser instructor

Foundations in an on-site, eight-hour course during which a Keiser Master Trainer teaches and applies all of the required information attendees need to become a Keiser indoor group cycling class instructor.

Download the M series instructor app

View live data from multiple bikes on one device and make class adjustments in real time with the free M Series Instructor App for Apple® or Android™ devices.

Keiser Videos

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