The Battle of the Bikes: The Diamondback 1260sc vs. the Keiser M3i 

Diamondback 1260sc vs Keiser M3i bike comparison

February 19, 2021

Indoor cycling brings with it a world of benefits, aside from convenience and comfort. It can help you burn calories and lose body fat while boosting your cardiovascular health and muscle endurance. Plus, it beats going to the gym in bad weather.

If you're thinking of getting into at-home fitness, then you should consider looking into spin bikes.

In this article, we'll be reviewing two of the best commercial-grade spin bikes for indoor cycling: the Diamondback Fitness 1260sc and the Keiser M3i.

Diamondback 1260sc vs. Keiser M3i

While it's designed for residential use, the Diamondback Fitness 1260sc Studio Cycle is built like a commercial-grade exercise bike that can accommodate riders of different sizes and weights.

Keiser's M3i is also a commercial-grade indoor exercise bike, but it differs from a traditional indoor cycle, which relies on the flywheel weight to achieve optimum results. It instead uses a unique, light flywheel system while delivering the same effects as its conventional counterparts, making the M3i the better choice for a workout using indoor bikes.

The Benefits of an Indoor Cycling Bike

Having a spin bike in your house makes training or exercise a more time-efficient activity. If you want to squeeze in a few minutes of cardio during the day, you absolutely can—all without having to leave your house to go to the gym.

With exercise bikes, you won't need to head outdoors, map out a route, and face the usual interruptions when you're on the road. You'll be able to focus on your training, whether it’s building your endurance or improving your overall performance.

Best of all, a modern indoor cycling bike is loaded with features that can keep your workout sessions more interesting. Most bikes can connect to apps that allow you to monitor your progress. Some also have Bluetooth connectivity. Today's bikes are designed to enhance the user's performance and training without compromising their comfort.

Key Features and Differences

Diamondback 1260sc

Keiser M3i

Diamondback 1260sc indoor cycle
Keiser M3i indoor cycle


31 lbs flywheel


8 lbs flywheel

Resistance Levels:


Resistance Levels:



Digital with WATT technology


Backlit LCD








4 way adjustable with multi-positional grips


 standard or SPD clipless pedals


cage integrated design


high-density foam saddle


four-way adjustable seat

HR Monitoring:

HR receiver ANT+ compatible

HR Monitoring:

HR receiver with M Series Apps


59"L x 23"W x 50"H


51"L x 26"W x 49"H

Max. User Weight:

300 lbs. 

Max. User Weight:

300 lbs. 

Max. User Height:

5'2" to 6'5"

Max. User Height:

4'10" to 7'


5 years for the frame and brakes, 3 years for parts and any electronic components, 1 year labor for a service technician


10 years for the frame and structural supports, 3 years for the cylinders and display, 2 years for the cables, bearings, and pulleys, 1 year on chrome

When choosing between the Diamondback Fitness 1260sc Studio Cycle and Keiser's M3i, here are some key factors you need to consider.

Design and Frame

The Diamondback Fitness 1260sc has a simple design with a standard heavy-duty frame. It also has a conveniently placed water bottle holder that's easy to access.

The M3i has a heavy-duty all-steel V-shape frame that's designed to accommodate riders of all body shapes and sizes up to 300 lbs. It's also sleek and modern, making it a great addition to any living room or home gym.


The 1260sc is belt-driven with a flywheel drive system that's 31 lbs. It can be precision-controlled using a dual magnetic resistance system. Meanwhile, the M3i has a self-tensioning, no-maintenance Poly-V belt drive that offers smooth movement and multiple adjustment options.

Levels of Resistance

With its magnetic resistance flywheel that’s rear-mounted, the 1260sc offers 16 resistance levels. The M3i, meanwhile, has almost infinite incremental resistance changes, giving users more versatility with their workouts. Its unique configuration and magnetic resistance provide a smooth and quiet workout session every time.


Equipped with a digital console, the 1260sc works with various apps and wearable tech that are compatible with ANT+ and BLE FTMS. It allows you to sync your data with heart rate monitors and activity monitors from brands such as Garmin and Wahoo, so you can better track your progress. It also works with iOS and Android, so you can use third-party apps such as Zwift and SPIVI.

The console displays your WATT output and keeps track of other essential details such as time, distance, calories, and RPM.

The M3i comes with an intuitive and simple-to-read console. It's backlit and displays information on one screen, including cadence, power, speed, distance, and rider time.


Both bikes feature Bluetooth connectivity that allows users to record and track their progress via compatible apps and wearable tech.


The 1260sc offers a customized experience for each rider. Aside from having an adjustable seat heat and saddle positioning, its handlebar height and fore or aft positioning are also adjustable. Additionally, its new handlebar configuration allows riders to use the bike with different riding height levels.

The M3i has adjustable handlebars with multi-positional grips, offering various riding experiences for each rider. It also comes with a smartphone or tablet holder that's mounted on the handlebar itself.


The 1260sc is equipped with versatile pedals and heavy-duty pedal cranks. Users can choose from standard or SPD clipless pedals to get the customized riding experience they need. The three-piece heavy-duty cranks offer a more reliable pedaling experience.

Featuring redesigned Keiser Bike Pedals, the M3i has pedals with stronger bearings for both static and dynamic loads, an integrated cage design, and ramped barbs that provide secure foot placement. The new design also includes a unique curvature that eliminates pressure points for more comfortable rides.


The 1260sc's seat is fully adjustable and allows riders to configure its height, as well as it saddle fore and after positioning. In comparison, the M3i also boasts an ergonomic, fully adjustable seat that you can adjust in four different ways.

HR Monitoring

Both bikes have Heart Rate monitoring. The 1260sc has an HR receiver that's ANT+-compatible and can be used with contact or wirelessly. With the M3i, you can train HR and use HR monitors such as the Polar H1 and T31 WearLink, both of which are compatible with the Keiser M Series bikes.


When assembled, the 1260sc has the following dimensions: 59"L x 23"W x 50"H. It weighs a total of 130 lbs. Meanwhile, the M3i's dimensions are as follows: 51"L x 26"W x 49"H. It weighs 92 lbs.

Max. User Weight

The 160sc and M3i can both accommodate users weighing up to 300 lbs.

Max. User Height

Those who are 5'2" to 6'5" can use the 1260sc. Meanwhile, the M3i offers more versatility when it comes to riders' heights, as it can seat users who are 4'10" to 7' tall.


The 1260sc's warranty covers five years for the frame and brakes, three years for parts and any electronic components, one year labor for a service technician, and 90 days for wear and tear items such as pedal straps, seat, and handlebars.

The M3i's warranty includes 10 years for the frame and structural supports, three years for the cylinders and display, two years for the cables, bearings, and pulleys, 1 year on chrome, and 90 days for the wear and tear components, including paint, upholstery, and rubber and plastic components.

Other Features

Both bikes come with transport wheels for easy movement.

The 1260sc has a spring ride saddle that offers extra cushioning and support to its users.

The M3i has a media tray, stretch pads, and a rear-wheel design that helps protect against sweat and corrosion. 


The 1260sc and M3i models come with a price tag of around $1,500 to $2,000, respectively. As they’re packed with various features that are useful for beginners and advanced riders alike, choosing either bike is a well-worth investment.

User Reviews

Customer reviews for both bikes are generally positive. For the 1260sc model, users liked its durability and smooth movement. A few recommended getting additional help to lift some of its pieces because of its heavier build.

Meanwhile, the majority of the M3i users appreciated the bike’s whisper-quiet operations and incredible adjustability. They also mentioned that it’s relatively easy to assemble, so long as you have all the tools required.

Considerations When Looking for an Indoor Cycling Bike

The wide range of styles and models available for indoor bikes can seem daunting for those who want to get into at-home fitness. To help you choose the right one for your needs, here are some factors that you need to consider before making any purchase:


Most bikes nowadays feature a sturdy construction and an all-steel build. These are usually powder-coated, not only for a sleeker look but also to make them longer-lasting. It goes without saying that bikes should be strong enough to handle a wide range of weights. It should also be stable enough, so users won't have to worry about it tipping over or being bent out of shape.


Another crucial factor that you should look into is a bike's adjustability, so you won’t have to compromise comfort. This includes the seat, handlebars, and resistance.


Choose a bike with a set of features that will benefit you the most. Some have easy-to-read LCD displays, while others have digital touchscreen consoles that are larger. Several bikes also come with pedal-foot restraint systems. Additionally, check if a unit has a built-in smartphone or tablet holder. You can also enhance it by adding accessories, such as an exercise bike mat and more comfortable seats.

Your Space

Check if the bike’s dimensions will suit your available space. See if it can also be stored easily when not in use.

Final Thoughts:

While both bikes offer pretty much the same benefits, they do vary in some aspects. The M3i has a one-up over the 1260sc with its unique flywheel configuration. It's smaller and more lightweight compared to conventional systems and offers nearly infinite resistance changes.

About the author 

Kevin Lee

Health and fitness have always been a passion for me; whether its being in the weight room, going for a run before work or even participating in a half iron man triathlon. ShapeJunkie was created to share to knowledge and love of fitness with others.

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