Last Updated on March 2, 2026 by
best mountain bike crank arms are essential components that directly affect your bike’s performance and pedaling efficiency. Choosing the right crank arms can improve your riding experience, durability, and compatibility with your bike setup.
Whether you are upgrading your mountain bike or replacing worn parts, factors like material quality, spindle interface, length, and installation ease matter most. In the USA, availability and compatibility with common bike standards are key considerations.
Below is a quick comparison table of top options, followed by detailed reviews to help you find the best mountain bike crank arms for your needs.
Quick Comparison: best mountain bike crank arms
| Product | Features | Best For | CTA |
|---|---|---|---|
| Epessa Crank Arm Left 170mm | Diamond & Square Interface High Quality Aluminum Alloy |
Reliable Replacement | Check Price |
| BUCKLOS Ebike MTB Crank Arm | Premium Aluminum Alloy Square & Diamond Hole Options |
Ebike & Versatile Bikes | Check Price |
| 2 PCS Bike Wheel Crank Arm | Solid Steel Construction Left Side Only |
Durable Left Crank Replacement | Check Price |
| Diamond Hole Bike Crank Arms | Forged Alloy 6061 Multiple Sizes Available |
Electric Bikes | Check Price |
| PROWHEEL Universal Square Crank | Forged Alloy 6061 Square Taper Interface |
City & Mountain Bikes | Check Price |
Our Top 5 best mountain bike crank arms
We selected five models for different needs and budgets, prioritizing feature quality, performance, fit/compatibility, reliability, and value.
Epessa Crank Arm Left 170mm
Overview
This crank arm suits riders needing a reliable left-side replacement with options for diamond or square spindle interfaces. It features high-quality aluminum alloy construction and fits 9/16 inch pedals.
Its 170mm hole spacing and 210mm total length ensure compatibility with many mountain and gym bikes in the USA. Confirm your right crank arm interface before purchase.
Specs
→ 2 spindle interface modes: diamond & square
→ Hole spacing length 170mm; total length 210mm
→ Fits 9/16 inch pedal
→ Material: high quality aluminum alloy
→ Compatible with many gym and mountain bikes
Pros
👍 Available in diamond and square interfaces
👍 Durable aluminum alloy material
👍 Fits standard 9/16 inch pedals
👍 Easy installation process
👍 Reliable replacement option
Cons
👎 Some gym bikes may be incompatible
👎 Requires matching interface on right arm
👎 Bottom bracket may need replacement after two crank changes
Customer Experience
Users praise its solid fit and straightforward installation, noting durable internal threads and great value for the price.
Best For
Reliable replacement for left crank arm on mountain and gym bikes.
BUCKLOS Ebike MTB Crank Arm
Overview
Ideal for ebikes and versatile mountain bikes, this crank arm set offers square and diamond hole options in multiple sizes. It is forged from premium aluminum alloy for sturdiness and longevity.
Easy to install with precision hole cutting, it fits various bike types including electric, folding, and fat bikes common in the USA.
Specs
→ Forged premium aluminum alloy
→ Square and diamond hole interface types
→ Sizes: 152mm, 170mm, 175mm available
→ Fits electric, mountain, folding, and fat bikes
→ Easy installation with precision hole cutting
Pros
👍 High quality forged aluminum alloy
👍 Multiple interface and size options
👍 Easy to install with precision holes
👍 Wide application on many bike types
👍 Suitable for electric bikes
Cons
👎 Mixed feedback on pedal quality
👎 Some concerns about build quality
👎 Pedal falling out reported by one user
Customer Experience
Customers find it a good quality, well-fitting crank arm set that works well on stationary and electric bikes, though pedal quality varies.
Best For
Ebike and multi-bike type crank arm replacement.
2 PCS Bike Wheel Crank Arm
Overview
Made of solid steel, this left-side crank arm set is built for strength and durability. It fits diamond hole center shafts and is suitable for mountain, road, folding, and fixed-gear bikes.
Its precise hole sizes ensure easy installation and consistent pedal height when paired with the correct right crank arm.
Specs
→ 2 pcs left cranks, 170mm center to center
→ Front round hole 2cm, rear diamond hole 1.6cm
→ Made of solid steel, high strength
→ Lightweight and easy to install
→ Fits multiple bike types including mountain and road
Pros
👍 Solid steel construction
👍 High strength and durability
👍 Precision holes for easy installation
👍 Suitable for various bike types
👍 Lightweight and compact design
Cons
👎 Left side only, requires matching right arm
👎 Image may confuse uninformed buyers
👎 Not compatible with all crank systems
Customer Experience
Users report a solid crank system that fits well on pressfit bikes but caution to verify compatibility before purchase.
Best For
Durable left crank arm replacement for multiple bike types.
Diamond Hole Bike Crank Arms
Overview
These forged alloy 6061 crank arms offer high strength and hardness with a diamond hole spindle interface. Available in ten sizes, they cater to extreme sports enthusiasts and general riders alike.
They are designed for electric bikes but can be used on mountain, road, folding, and city bikes with matching diamond hole interfaces.
Specs
→ Forged Alloy 6061 material
→ Available in 10 sizes from 89mm to 175mm
→ Diamond hole spindle interface
→ Left and right arms included
→ Suitable for electric and other bike types
Pros
👍 Durable forged alloy construction
👍 Wide size range for fit customization
👍 Clear left/right installation markings
👍 Compatible with diamond hole bikes
👍 Includes crank bolts and hardware
Cons
👎 Only for diamond hole spindle bikes
👎 Pair mainly for electric bikes
👎 Installation requires attention to side markings
Customer Experience
Buyers appreciate the correct fit and sturdy feel, noting they are sensibly sold in pairs even if only one arm is needed.
Best For
Electric bikes and diamond hole spindle users.
PROWHEEL Universal Square Crank
Overview
This forged alloy 6061 crank arm set features a square taper spindle interface and fits various bike types including city, road, folding, mountain, and electric bikes. It comes in multiple lengths to suit rider preferences.
Installation is straightforward with clear left and right arm markings, ensuring proper fit and function.
Specs
→ Forged alloy 6061 construction
→ Crank arm lengths: 152mm to 175mm
→ Square taper spindle interface
→ Includes chainring screws and crank bolts
→ Fits multiple bike types
Pros
👍 Strong forged alloy material
👍 Multiple length options
👍 Clear left/right arm markings
👍 Includes installation hardware
👍 Compatible with square taper spindles
Cons
👎 Only fits square taper spindle bikes
👎 Requires correct side installation
👎 No color options beyond black
Customer Experience
Users find it well-made, lightweight, and effective at improving bike fit with smaller crank options.
Best For
City and mountain bikes with square taper spindles.
Buying Guide: best mountain bike crank arms
Material and Durability
Spindle Interface Compatibility
Verify your bike’s spindle interface type—common options include square taper and diamond hole. Matching the crank arm interface to your bike’s bottom bracket is crucial for proper fit and function.
Crank Arm Length
Choose a crank arm length that suits your riding style and body size, typically between 152mm and 175mm. Shorter cranks offer quicker cadence, while longer cranks provide more leverage for power.
Installation and Fit
Look for crank arms with clear left/right markings and precision hole cutting to simplify installation. Some models include necessary hardware, reducing the need for extra tools or parts.
Bike Type and Usage
Consider the type of bike you have—mountain, electric, road, or folding—and select crank arms designed for that use. Some crank arms are optimized for ebikes or specific bike models.
FAQs: best mountain bike crank arms
What is the best material for mountain bike crank arms?
Forged aluminum alloy and solid steel are preferred for their strength and durability on rough terrain.
How do I know which spindle interface my bike uses?
Check your current crank arm or bottom bracket for square taper or diamond hole markings, or consult your bike’s specifications.
Can I install crank arms myself?
Yes, many crank arms come with clear instructions and hardware, making installation possible with basic tools.
Do crank arm lengths affect riding performance?
Yes, shorter arms allow faster pedaling cadence, while longer arms provide more torque and power.
Are these crank arms compatible with electric bikes?
Some models are specifically designed for ebikes, so verify compatibility before purchasing.
How often should I replace my crank arms?
Replace crank arms when you notice wear, damage, or poor fit, typically after several years of use depending on riding conditions.
Can I mix different crank arm brands?
It’s best to use matching crank arms for left and right sides to ensure proper fit and pedal height.
Final Verdict: best mountain bike crank arms
For reliable left crank replacement, the Epessa model offers solid value and durability. BUCKLOS suits ebike riders needing versatile options. Steel crank arms like the 2 PCS Bike Wheel set provide rugged durability. Diamond hole crank arms fit electric bikes well, while PROWHEEL is ideal for square taper spindle users seeking lightweight options.
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