Keiser M3i Indoor Bike Review

We purchased the Keiser M3i Indoor Bike so our expert reviewer could thoroughly test and assess it. Keep reading for our full product review.

Finding the motivation to head outside for a run or a bike ride can be daunting when you’re dealing with a heat index of 100+ (ditto for when the weather turns cold). Indoor exercise equipment like the Keiser M3i Indoor Bike can help you run out of excuses. I was looking for something to keep me on a regular exercise schedule—something that was somehow enjoyable while still making me really work for it—so I turned to the Keiser.

Considered one of the top indoor cycling bikes you can buy, this model sets out to do a couple of things: fit riders of all sizes and feel like a real bike ride. It’s often used in gyms for group cycling, but you needn’t sign up for the gym in order to take advantage of the bike in your own home. I tested this product in the comfort of my living room, sweating it out with digital spin classes, to give you the most comprehensive review possible. Read on to learn whether the Keiser M3i Indoor Bike is right for you.

Setup Process: Check your toolbox before beginning

This bike arrived in a large, heavy box that made me thankful for my building’s elevator and a helpful delivery person. Though it was initially daunting, actually assembling the bike wasn’t as difficult as I expected. 

Before you begin, take a look at the manual to make sure you have all the tools. I needed to pick up an extra Allen wrench and rust inhibitor, along with a torque wrench. Once I had all the tools, I managed to put together the bike in about an hour. 

The longest part of the process? Opening the box and unwrapping the parts. The instructions suggest that two people work together on the bike due to its weight, but I’m fairly small-statured and managed just fine on my own.

Design: Modern and adjustable 

The Keiser M3i is often used by gyms for indoor cycling classes, so it’s designed to work with different-sized users (it adjusts for heights from 4-foot-10 to 7-foot and up to 350 pounds). The company claims to be the first to engineer a V-shape frame, which mimics road bikes by enabling the seat and handlebar to be raised in conjunction with each other.

The flywheel is located at the back of the bike. While that might look odd at first, its placement is intentional in order to keep sweat from ruining the flywheel. In fact, all the important parts of the bike are placed behind the rider, where they’re safe from the sweat zone. This includes the drivetrain, which consists of a single Poly-V belt and helps the rider reach higher speeds. Keiser says this placement makes the bike less vulnerable to corrosion and maintenance needs. 

The resistance handle is situated directly in front and spans from 0 to 88; the highest setting acts as the emergency brake. The resistance works via magnetic resistance, which reduces wear and tear on the flywheel because it never actually touches it. This use of magnetic resistance allows lends itself to the road-bike feel of the Keiser M3i.

No detail has been overlooked with this bike, right down to the design of the pedals. For one, the curve of the pedal is made to eliminate pressure points on the foot, and the cage is integrated into the pedal design rather than added on. Keiser put together a whole video on the pedal design, which you can watch here. There’s even a ridge or “stretch pad” located at the back of the bike to make it easier to stretch before and after working out.

In terms of overall style, no exercise bike was going to blend in with my home completely, but the Keiser M3i does the best it can. Compared to other top exercise bikes on the market, it has a sleek, modern look that I don’t mind leaving out in view when I have to (and usually, I have to—though the bike isn’t huge, it’s not fitting into any of my closets). If you do leave it out, the manufacturer recommends leaving 24 inches open on every side.

Performance: A spin class experience in your living room

After adjusting the bike for my 5-foot-2-inch frame, I slipped my feet into the pedals and got to work. This bike had me sweating like no other exercise can. I followed a spin class via my phone, which was easy to do because of the included media tray that provides a place for a phone or tablet. You can easily find classes on YouTube or apps like the Keiser MSeries app, which syncs with the bike. There’s space for a water bottle, too, which is incorporated into the design and located along the V frame of the handlebars. 

The built-in bike computer kept track of my stats and provided RPMs, watts, calories, time on bike, and trip distance. It also shows what gear (resistance level) you’re using, and if you have a heart rate monitor, your heart rate. This bike received the TÜV’s EN957-10 Certification for Power Accuracy and Safety (in fact, it was the first indoor bike to be certified), so I felt confident that I was getting accurate data.

I found the screen to be slightly dim, but it does have a backlight that automatically turns on when it senses a darkened room. This feature is automatic, and there is no way to turn the backlight on or off manually. Once it does turn on, it stays on for the rest of the ride. The bike computer works via Bluetooth, so you can also send your data directly to the Keiser app on your phone (more on that later). 

One of my favorite things about the bike is how quiet it is. Thanks to the use of magnetic resistance, there’s no loud whooshing of the wheel or unnecessary noises. Someone could easily watch TV in the same room without being disturbed. Overall, exercising on the Keiser M3i is comfortable and effective. I plan to continue to use it as part of my exercise routine.

Comfort: Comfy handles and pedals, but seat could be better

Because I’m on the shorter side, some exercise bikes can be uncomfortable, but with the completely adjustable handles and seat, I didn’t have this problem with the M3i. In fact, the seat has four-way adjustment and can be raised or lowered and moved forward and back to help you find the perfect position—a desirable feature to look for when shopping for an indoor cycling bike. The handlebars do the same and are comfortable to use whether you’re sitting or standing and with whatever hand position you choose to use.

I found the pedals comfortable to use, and they felt strong and secure during my rides. The shoe cage adjusts easily using a strap that pulls to tighten, so there are no clunky buckles like on other spin bikes I’ve used. My husband, who is significantly taller than I am, also tested the bike and had no issues adjusting the seat and handlebars to fit his frame.

The one thing I didn’t find comfortable was the included seat. Though it’s covered in smooth, soft leather that continues the elegant design of the bike, I found it to be a bit harsh after about 15 minutes. For this reason, I’ll be purchasing a new bike seat or cover.

Compatibility: Purchase a converter to expand connections

The Keiser M3i differs from other indoor bikes in the same line because of its Bluetooth capabilities. The bike computer connects with your devices to send your exercise data to your phone, offering a convenient way to track and compare workouts from other fitness apparatus, such as rowing or elliptical machines. Connecting was easy and fairly automatic.

I tried out the free Keiser MSeries app, which is the suggested way to connect to the bike. Once I started pedaling, I was presented with three options: Free Ride, FTP Test, and Guided Session. Free Ride, as the name suggests, simply tracks the ride statistics and saves them within the app. It tracks the same stats that you see on the bike’s computer, along with graphs of both power and cadence. 

The FTP test, or Functional Threshold Power test, measures the amount of power (watts) you can sustain for an hour, and it gives you a measurement of your fitness. Taking this test will set guidelines for the third option, the Guided Session workouts. The Guided Session option lets you choose from a selection of about 11 workouts, all within the 45- to 60-minute range. There’s a power workout, interval workouts, and FTP improvement workouts—all customized to you based on your previous performance in the FTP test.

The workouts guide you to stay within a certain RPM, watt, and gear range and indicate on the screen if you need to make these numbers higher or lower. After you’re done, your results are saved onto your phone. I prefer classes with a live instructor, but I still enjoyed these classes for the hard workout I got from them. I can see myself eventually wanting something new, however, since there are so few classes available. 

If you want to expand the compatibility of the bike, you can purchase an M Series Converter from Keiser for $99, which allows the bike to connect to apps like Zwift, The Sufferfest, BKOOL and many others. This converter works by literally converting the Bluetooth information from the bike into data that is useable by other apps.

In order to use the heart rate feature, you will need to pick up a compatible heart rate-measuring device. I used the Polar H10 chest strap heart rate monitor, and it automatically connected to the bike. Keiser recommends Polar brand monitors, like the Polar H1 and T31 WearLink models. Depending on where you purchase the indoor bike, it may already be included in your order. If you order from Keiser directly, a heart rate monitor is included.

Features: A solid warranty

When purchasing something pricey, a good warranty can be the difference between going for it and holding back. Fortunately, I feel that Keiser has a relatively good warranty. The wearable parts of the bike—as defined as the "T" handles, pedal cage, pedal strap, and saddle upholstery—are guaranteed free of defects for three months. The rest of the bike is under warranty for three years. You can see more on Keiser’s site. Keep in mind this bike is frequently in high-use, gym class situations, so this warranty likely covers much more wear and tear than a single owner could ever put on it.

I also really appreciated the floor mat that came with the bike. Though it’s meant to keep sweat off the floor, I also felt that it helped stabilize the bike, along with the rear, adjustable leveler. When I needed to move the bike, the two wheels on the front end were helpful. I did think they were placed too high on the bike, but this could be a consequence of my small frame. It was a bit nerve-inducing to flip the bike on its head so much and then subsequently lower all 85 pounds.

Price: An expensive, high-end bike

This bike isn’t cheap. At $1,995, it’s as high-end as you can get. But what you pay for in cash, you get back in quality. Though you can purchase an exercise bike for just a few hundred dollars, spending more will get you quality craftsmanship and bonuses like a quieter and more comfortable ride. 

This is a bike that is often used in gyms and spin classes, so the price gets you a professional piece of equipment without a gym membership. Because of the craftsmanship and warranty, the bike should last for years and years with limited maintenance needed. 

Competition: Consider the monthly fees for each

Peloton: Potential buyers might weigh whether the Keiser or the similarly priced Peloton is a better buy. For the most part, it comes down to whether you want a bike that requires a subscription feature or not (and whether that feature is worth the cost for you). While the Keiser M3i can be used without a monthly subscription, the Peloton requires a monthly payment of $39.99. 

If you enjoy Peloton classes but not the subscription, you can still access classes through the Peloton app for $12.99 a month and use them with the Keiser. Though it won’t be the same experience, it gives you the freedom to choose how you want to use the bike. And with the aforementioned M Series Converter, you can participate in those classes just like you have a Peloton.

Other Keiser M3 Series Indoor Bikes: The biggest difference between the Keiser M3i and the other bikes in the M3 series is its Bluetooth connection, along with fore-and-aft-handlebar adjustments (which moves the handlebars closer or farther from your body). And while the M3i is a road bike experience, the M3X simulates mountain biking or hill climbing. The M3iX comes with the road bike feel plus Bluetooth, but it doesn’t have the fore-and-aft handlebar adjustment.