The Keiser M3i Indoor Bike – Everything You Need To Know Before You Buy [A Review]

Keiser’s M3i has earned a stellar reputation and is generally considered one of the best indoor cycles on the market.

With a fast-spinning, lightweight flywheel, the M3i is able to provide a smooth pedaling motion, while still keeping the overall weight of the cycle down, making it easy to move compared to other, bulkier cycles.

And with a sophisticated magnetic resistance system and commercial grade belt drive, this bike operates quietly, so you certainly won’t have to worry about bothering family members during workouts.

The M3i is also able to fit riders of most heights comfortably, making it accessible for folks of all sizes.

All things considered, I agree with the consensus that the M3i is a fabulous cycle, but is it really the right bike to meet your needs?

That’s what I’m here to help you figure out.

In this review, I’ll go over everything you should be aware of before deciding on this bike.

After reading, you’ll be well prepared to decide for yourself whether or not the M3i is worth investing in.

Let’s begin.

The Keiser M3i Indoor Bike

Even though most of us probably know Keiser for their elite indoor cycles, the fitness brand really made a name for themselves in the world of professional sports.

Keiser also has a full lineup of pneumatic resistance equipment that’s become a popular training choice for pro athletes in all sports.

The idea being that the pneumatic resistance varies throughout your range of movement, allowing you to trainer at faster speeds, while minimizing stress to the soft tissues and joints.

Very cool stuff.

Anyway, Keiser started with their resistance training equipment and eventually expanded into the indoor cycling market.

At the time of writing this, Keiser offers 2 cycles to choose from: the original M3 and the M3i we’re here to discuss now.

The M3i comes with a few key upgrades over the M3, but the M3 is still a great cycle in its own right.

Let’s start this review off with a look at this bike’s resistance system.


  • Fast spinning, light weight flywheel
  • Micro-adjustable magnetic resistance
  • 24 gear levels
  • Bluetooth compatible with fitness apps
  • Dual-compatible pedals
  • Fully adjustable seat
  • Fully adjustable handlebars
  • Fits folks of most heights
  • Weight limit of 350 lb
  • Polar H9 heart rate monitor included
  • Dumbbell holders
  • Floor mat
  • Toolkit included
  • Media tray
  • Good warranty


  • No built-in workout programs
  • No water bottle holder
  • Dumbbells not included


I mentioned in the intro that the M3i uses a light flywheel and this is certainly one of the key features of this bike.

The belief that heavier is better has generally become accepted when it comes to exercise bikes and flywheels, but that’s only really the case if the bike is designed to benefit from a heavier flywheel.

And it turns out, most home bikes are designed that way.

And it’s really because adding mass to the flywheel is an affordable way to improve the feel of the pedaling motion.

It all comes down to momentum – a heavier flywheel is going to build more momentum as it spins, which in turn helps keep the pedals moving a little between pedal strokes.

This is what eliminates any unwanted lag between your upstroke on one side and your downstroke on the other, making for a better overall feel.

Well, turns out you can build momentum by increasing the speed at which that flywheel spins too.

This takes a more sophisticated design, but it works just as effectively (some would even say it creates a better feel).

Keiser only uses an 8 lb flywheel, but that flywheel spins about 11x for every full rotation of the pedals (1:11 gear ratio) – which means that flywheel gets moving really fast during workouts.

This flywheel speed builds all the momentum needed to keep those pedals moving smoothly and users are pretty unanimous in their feelings that the M3i offers a great feel.

Again, most indoor cycles go the heavy-flywheel route because it’s a cheaper way to build momentum, but there are other cycles out there that utilize light flywheels (the ICG cycles come to mind).

Having a light flywheel also makes the M3i a little easier to start from a dead stop and can even help reduce strain on your joints, compared to a traditional heavy flywheel design.

Keiser pairs this 8 lb flywheel with a magnetic resistance system that comes with 24 digital “gears”, but technically it’s a micro-adjustable system because you can make adjustments to the resistance between gears too.

Personally, I’d prefer a system that registers each resistance level because it makes it easier for me to replicate workout conditions and track my progress.

But with the gear levels, you’ll be able to replicate workout conditions pretty easily too.

Oh, the M3i also comes with a high-end, maintenance free belt drive, so you won’t have to worry about lubricating the belt or anything like that.

It’ll also operate very quietly, which is always a good thing.

Overall, the M3i scores highly with its fast spinning flywheel and smooth magnetic system and users have few complaints regarding this cycle’s performance.


I’m usually a proponent that having a heavier bike is a good thing because the extra weight helps stabilize the bike – making it less likely to wobble around during workouts.

But when looking at the M3i, we have to keep in mind that it doesn’t have a heavy flywheel adding to the total weight of the bike.

So, with an assembled weight of 92 lb, the M3i is quite a bit lighter than most other cycles in this price range, but again, it’s only packing an 8 lb flywheel.

For the sake of comparison, the Peloton Bike weighs around 135 lb, but it’s packing a 35 lb flywheel.

That said, ICG’s IC4 uses a 7.6 lb flywheel and still weighs in at around 110 lb, making it quite a bit heavier-duty.

Even though the assembled weight is lower on the M3i, users of all sizes seem to agree that the frame feels stable and secure during workouts.

I haven’t come across many complaints at all regarding the quality of this cycle.

According to Keiser, the M3i should be able to fit most riders between 4’10” – 7′ tall, which is pretty amazing for an indoor cycle.

This is mostly due to the “V shaped” frame design, which allows the seat and handlebars to move out horizontally as you adjust the height.

This cycle also comes with an impressive weight capacity of 350 lb, again allowing folks of most sizes to safely access it.

Otherwise, the M3i takes up a foot print of roughly 4′ x 2′, give or take a few inches, which is standard for most indoor cycles.

Overall, the M3i’s frame is lighter than many other cycles, but that doesn’t seem to affect its stability one bit. And I love that this bike can accommodate riders of so many heights and sizes.


The Keiser M3i comes with the following residential warranty:

  • 3 year frame
  • 3 year parts
  • 90 day wearable items

Ok, I’d prefer to see a lifetime frame warranty here, but to be fair – there aren’t that many brands offering those these days, even in this price range.

Three years on the frame is still pretty short, considering most elite cycles offer 5 – 10 years, but the good news is it’s rare for the frame to breakdown on ya.

Three years on the parts is pretty good, considering most other brands offer 2-3 years on parts.

90 days on wearable items is pretty short, but I don’t consider this that serious of an offense.

For the sake of comparison, the similarly priced IC4 I mentioned earlier comes with a 10 year frame, 3 year parts, and 1 year labor warranty.

NordicTrack also offers a 10 year frame, 2 year parts, and 1 year labor guarantee on their Commercial S22i.

Overall, the M3i’s parts warranty is good, but its frame guarantee could definitely be longer.


The Keiser M3i Indoor Bike comes with the following features:

M Connect console- the console on the M3i is fairly small, but it’s brightly lit, making it easy to read all your metrics in real time during workouts. There aren’t any built-in workouts or anything like that, but this console is bluetooth compatible with most fitness apps, including Keiser’s own M Series app. A lot of riders have mentioned they like to pair the M3i with Peloton’s Digital App, which seems to work great.

Polar H9 heart rate monitor- the console is compatible with strap heart rate monitors and Keiser does ya one better by including one with purchase.

Fully adjustable seat- you can adjust both the height and horizontal (fore/aft) position of the seat, making it easier to find the best riding position for folks of all heights.

Fully adjustable handlebars- the handlebars on this cycle are also fully adjustable, which is one of the biggest upgrades the M3i has have the original M3. The handlebars on the M3i are also more ergonomically inclined, offering more comfortable grips.

Dual-compatible pedals- the pedals come with a toe cage on one side and are SPD compatible on the other, allowing you to wear sneakers or cleats during your workouts (fyi – some riders find it helpful to remove the straps when using the SPD side because the straps can make a little noise when pedaling).

Dumbbell holders- there’s a place to store small dumbbells on your bike, which comes in handy when following Peloton style workouts (you have to provide your own dumbbells though).

Floor mat- Keiser throws in a floor mat with purchase, allowing you to protect your floor.

Media tray- there’s also a place to hold your phone/tablet during workouts, which is convenient when using fitness or entertainment apps.

Tool kit- Keiser also includes all necessary tools for assembly.


At the time of writing this, Keiser’s M3i costs $2,160.

This price may vary throughout the year, but this bike’s price has been fairly stable over the last few years, so I assume it’ll always be somewhere around $2k.

I agree $2k is a sizable investment for an indoor cycle, but it’s in the right ballpark when compared to other elite cycles.

The Peloton Bike+ and NordicTrack’s Commercial S22i are both pushing $2k and the IC4 mentioned earlier is just a tad over $2k.

ICG also has several indoor cycles that cost quite a bit more than the M3i (their IC7 is pushing $4k at the time of writing this).

Based on these other cycles, I think Keiser’s asking price for the M3i is fair based on what you get.

Final Thoughts

Well, that’s about all I got regarding the M3i.

Something I forgot to mention earlier, is that Keiser was the first brand to use magnetic resistance on their indoor cycles and they were also the first ones to put the flywheel in the back.

Both of which have been replicated by fitness brands around the world.

We have Keiser to thank for a lot of the innovations that indoor cycling has appreciated over the last few decades and I think it’s a real testament to what the folks behind this brand are doing.

Anyway, I think the M3i is an impressive bike.

Folks looking for an elite cycle that can perform and deliver accurate power measurements will likely be very pleased.

The console doesn’t come with any workouts or speakers or fans, so if you’re looking for more of that stuff, you should probably go with another cycle.

Overall though, I think the M3i is still one of the best indoor cycles on the market today. Highly recommended.

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