5 Best 120mm Mountain Bikes [In 2025]

Last Updated on August 25, 2025 by Jaxon Mike

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When it comes to mountain biking, having the right bike can make all the difference in your riding experience. The best 120mm mountain bikes offer a versatile and well-rounded package that can handle a variety of terrain and riding styles. Whether you’re tackling technical singletrack, cruising down flowing trails, or conquering steep climbs, a 120mm bike can provide the perfect balance of suspension, geometry, and capabilities.

5 Best 120mm Mountain Bikes Reviews

BAFANG Mid Drive Kit 1000W BBS-HD Electric Bike Conversion Kit

Overview

The BAFANG Mid Drive Kit 1000W BBS-HD Electric Bike Conversion Kit is a powerful and versatile option for transforming your existing mountain bike into an electric bike. This kit features a high-torque 1000W motor, a range of display and battery options, and comprehensive compatibility with a variety of bike frames and components.

Specs

• Motor: 1000W BAFANG mid-drive motor with 160 N.m of torque
• Battery: Compatible with 48V and 52V electric bike batteries (sold separately)
• Display: Optional displays include VD03, EKD01, VD04, VD618, VD61, DPC010, and DPC080
• Compatibility: Fits bottom brackets with 68-73mm, 100mm, or 120mm lengths and 33.5-36mm inner diameters
• Includes: Motor, brake lever, chainwheel, thumb throttle, speed sensor, headlight, and more

Pros

• Powerful 1000W motor with high torque for tackling hills and off-road terrain
• Versatile compatibility with a wide range of bike frames and components
• Comprehensive accessory kit makes installation and customization easy
• Offers throttle, pedal assist, and standard cycling modes for a personalized riding experience

Cons

• Battery and display are sold separately, adding to the overall cost
• Installation may require some technical know-how and time
• Not compatible with carbon fiber frames or bikes with pedal brakes

Customer Reviews

Customers who have installed the BAFANG Mid Drive Kit 1000W BBS-HD Electric Bike Conversion Kit are generally very satisfied with their purchase. Many praise the kit’s power, versatility, and ease of installation, with one reviewer noting, “As I am getting older, I want to get back into bicycling being retired and all after pricing ebikes and already having a bike that was comfortable I decided to try a conversion kit and am very happy I did the kit was not that hard to install.”

BAFANG 500/750/1000W Mid Drive Kit

Overview

The BAFANG 500/750/1000W Mid Drive Kit is another high-performance electric bike conversion option for your mountain bike. This kit offers a range of motor power outputs, from 500W to 1000W, allowing you to choose the level of performance that best suits your needs and terrain. Like the previous BAFANG kit, this conversion system provides comprehensive accessories and customization options.

Specs

• Motor: Available in 500W (100 N.m), 750W (120 N.m), or 1000W (160 N.m) options
• Battery: Compatible with 48V and 52V electric bike batteries (sold separately)
• Display: Optional displays include VD03, EKD01, VD618, VD61, DPC010, and DPC080
• Compatibility: Fits bottom brackets with 68-73mm, 100mm, or 120mm lengths and 33.5-36mm inner diameters
• Includes: Motor, display, sprocket, speed sensor, brake lever, crank, and more

Pros

• Offers three power output options to suit different riding needs and terrain
• Comprehensive accessory kit and customization options for a personalized setup
• Upgraded features like dual Hall speed sensors and battery communication function
• Wide compatibility with various mountain bike frame sizes and styles

Cons

• Battery and display are sold separately, adding to the overall cost
• Not recommended for use with carbon fiber frames or bikes with pedal brakes
• Installation may require some mechanical expertise and time

Customer Reviews

Customers who have installed the BAFANG 500/750/1000W Mid Drive Kit generally report positive experiences. They appreciate the power and performance of the motor, as well as the wide range of customization options. One reviewer noted, “This upgraded ebike conversion kit has upgraded current output stability, upgraded dual Hall speed sensors, battery communication function, and added taillight cable, providing better riding performance and experience.”

31.8 Bike Handlebar – 25mm, 55mm, 70mm, 90mm,120mm Riser Handlebar

Overview

The 31.8 Bike Handlebar is a high-quality, versatile mountain bike handlebar that can help enhance the performance and comfort of your 120mm trail bike. With a range of rise options and a wide, 780mm width, this handlebar is designed to provide a modern, ergonomic riding position and improve control on the trail.

Specs

• Diameter: 31.8mm clamp
• Width: 780mm
• Rise: Available in 25mm, 55mm, 70mm, 90mm, and 120mm options
• Material: 6061 aluminum alloy
• Sweep: 12 degrees rearward

Pros

• Wide, 780mm width provides excellent control and stability
• Rearward sweep helps put the rider in a more neutral, comfortable position
• Durable and responsive 6061 aluminum alloy construction
• Multiple rise options to suit different riding styles and preferences

Cons

• Requires careful installation and alignment to ensure proper fit and handling
• Some customers have reported issues with the diameter not matching the stated specifications

Customer Reviews

Customers who have purchased the 31.8 Bike Handlebar generally praise its quality, comfort, and performance. One reviewer noted, “Easy to misposition the roll and worsen steering geometry – worked better for me after i aligned the mid point of the roll marking with the mid plane of my stem. The high rise works great on steep descents, i feel more in control. It is also vastly more comfortabel when pedaling on flat and uphill on most ascents.”

CYSKY 10° 17° Bike Stem 31.8 60/70/80/90/100/110/120/130mm MTB Stem

Overview

The CYSKY 10° 17° Bike Stem is a high-quality, adjustable stem that can be used to fine-tune the handling and fit of your 120mm mountain bike. With a range of length options and a 17-degree angle, this stem allows you to customize the rider position and improve control on the trail.

Specs

• Diameter: 31.8mm handlebar clamp, 28.6mm fork clamp
• Length: Available in 60mm, 70mm, 80mm, 90mm, 100mm, 110mm, 120mm, and 130mm options
• Angle: 17 degrees
• Material: 6061 T6 aluminum alloy
• Weight: 150g (0.33 lb)

Pros

• Adjustable length and angle allow for customized fit and handling
• Durable and lightweight 6061 T6 aluminum alloy construction
• Easy to install and secure the handlebar in place
• Suitable for a wide range of mountain bikes, from XC to downhill

Cons

• Some customers may prefer a different angle or rise than the 17-degree option
• Careful installation is required to ensure proper fit and handling

Customer Reviews

Customers who have purchased the CYSKY 10° 17° Bike Stem generally report positive experiences, with one reviewer stating, “Well made with a smooth forged finish, light, and aesthetically pleasing. Almost hard to believe low cost butit is real. Go spend much more if you want, the stem will not be better.”

BAFANG Mid Drive Motor Kit – 750W/1000W/500W Ebike Conversion Kit

Overview

The BAFANG Mid Drive Motor Kit is another versatile electric bike conversion option for your 120mm mountain bike. With power output choices ranging from 500W to 1000W, this kit offers a level of performance to suit a variety of riding needs and terrain. It also features a comprehensive accessory package and customization options to create a personalized electric bike setup.

Specs

• Motor: Available in 500W, 750W, or 1000W options
• Battery: Compatible with 48V and 52V electric bike batteries (sold separately)
• Display: Optional displays include VD03, EKD01, VD04, VD618, VD61, DPC010, and DPC080
• Compatibility: Fits bottom brackets with 68-73mm, 100mm, or 120mm lengths
• Includes: Motor, brake lever, chainwheel, thumb throttle, speed sensor, headlight, and more

Pros

• Offers a range of power output options to suit different riding needs and terrain
• Comprehensive accessory kit and customization options for a personalized setup
• Upgraded features like dual Hall speed sensors and battery communication function
• Wide compatibility with various mountain bike frame sizes and styles

Cons

• Battery and display are sold separately, adding to the overall cost
• Not recommended for use with carbon fiber frames or bikes with pedal brakes
• Installation may require some mechanical expertise and time

Customer Reviews

Customers who have installed the BAFANG Mid Drive Motor Kit generally report positive experiences, with one reviewer noting, “Unlocking the Full Potential of Your e-Bike with Our Premium Accessories! At BAFANG, we pride ourselves on delivering top-tier e-bike accessories that not only meet but exceed your expectations.”

Buying Guide: Choosing the Best 120mm Mountain Bike

Suspension and Travel

• 120mm of suspension travel is a versatile sweet spot for many trail riding situations, providing a comfortable and capable ride across a variety of terrain.
• Look for a bike with high-quality suspension components, such as air-sprung forks and shocks, that can be tuned to your preferences.
• Consider the bike’s geometry and how it will affect the handling and stability at the 120mm travel level.

Frame and Components

• Opt for a durable and lightweight frame, often made of aluminum or carbon fiber, that can withstand the demands of trail riding.
• Ensure the bike’s components, such as the brakes, drivetrain, and wheels, are well-suited for the type of riding you’ll be doing.
• Look for features like thru-axles, tubeless-ready tires, and hydraulic disc brakes that can enhance performance and reliability.

Geometry and Fit

• Consider the bike’s geometry and how it will affect the handling and fit for your riding style and body type.
• Pay attention to the bike’s reach, stack, and head tube angle, as these can impact the bike’s stability and responsiveness.
• Ensure the bike’s size and fit are appropriate for your height and riding preferences, as this can significantly impact comfort and control.

Electric Conversion Kits

• If you’re interested in converting your 120mm mountain bike to an electric bike, consider kits like the BAFANG offerings that provide powerful motors, comprehensive accessories, and customization options.
• Ensure the kit is compatible with your bike’s frame and components, and research the installation process to make sure it’s a good fit for your skill level.
• Factor in the additional weight and power delivery when choosing a conversion kit to maintain the bike’s handling and performance characteristics.

Accessories and Upgrades

• Consider upgrading components like the handlebars, stem, and seatpost to further optimize the bike’s fit and handling characteristics.
• Look for accessories like dropper posts, suspension tuning kits, and protective gear to enhance your riding experience and safety.
• Ensure any upgrades or accessories you choose are compatible with your 120mm mountain bike’s frame and components.

FAQ

What are the benefits of a 120mm mountain bike?

A 120mm mountain bike offers a versatile balance of suspension travel, geometry, and capabilities. It can handle a wide range of trail conditions, from flowing singletrack to more technical terrain, while providing a comfortable and stable ride. The 120mm travel range is a popular sweet spot for many all-around trail riding applications.