BUCKLOS MTB Single Speed 104BCD Crankset - Lightweight Durable Upgrade

In this review of the BUCKLOS MTB Single Speed 104BCD crankset the bottom line is clear: this is a practical, lightweight upgrade for single speed mountain, commuter, and electric bikes where simplicity and reduced weight matter most. The crankset delivers a dependable square taper interface and a choice of narrow-wide chainrings that improve chain retention and save weight compared with multi-ring setups. Installation is straightforward for anyone comfortable with basic hand tools, so riders seeking a clean, single-speed drivetrain will find a lot to like here.

Key Features

• Ultralight crankset: The 104 BCD crankset weighs about 609g, reducing rotating mass for a snappier feel on climbs and accelerations.
• Narrow-wide chainring: Available in 32/34/36/38/40/42T and round or oval shapes, the chainring holds the chain securely for single speed use and fits common crank standards.
• Durable construction: Built to last for mountain bikes, commuter bikes, and e-bikes, the crankset balances low weight with longevity for regular riding.
• Single speed design: The crank and chainring are intended for single speed drivetrains only, simplifying setup and reducing maintenance.
• Easy to install: The square taper interface and included chainring bolts make installation simple for riders familiar with a hex wrench.
• Multiple color and shape options: Choose black or red and round or oval chainring profiles to match ride preference and bike aesthetics.

Who It's For

This crankset is aimed at riders who want a straightforward, lightweight single speed solution for a mountain bike, commuter bike, or e-bike conversion. It suits riders upgrading from heavy multi-chainring setups or stock cranks, and those who prioritize chain retention and a cleaner drivetrain layout.

Riders who need a multi-speed compatible crankset or integrated bottom bracket systems should look elsewhere, as this product is explicitly for single speed use and uses a square taper interface rather than modern integrated spindle standards.

Pros & Cons

Pros

• Lightweight design at about 609g gives a noticeable weight saving over 3x setups.
• Choice of chainring sizes and oval or round profiles offers tuning for cadence and gear feel.
• Easy installation for anyone comfortable with basic tools and hex wrenches.
• Good value and solid build quality reported by riders upgrading older bikes.

Cons

• Only suitable for single speed drivetrains, so it is not compatible with derailleurs or multi-speed setups.
• Uses square taper interface, which may not fit frames requiring modern spindle crank standards without adapters.

Specifications

Brand	BUCKLOS
Crankset weight	About 609g
Chainring options	32/34/36/38/40/42T, round or oval
Chainring thickness	Narrow 1.9mm / Wide 3.7mm (4mm overall)
Compatibility	Fits single speed bikes; compatible with Shimano, SRAM, FSA chainrings
Mount type	104 BCD, square taper
Package contents	1 crankset, 1 single speed chainring, 4 chainring bolts

Our Verdict

The BUCKLOS 104BCD single speed crankset is a sensible, cost-effective upgrade for riders who want to simplify their drivetrain and shed weight without complex installation. Its narrow-wide chainring options and reliable square taper design make it a practical choice for mountain, commuter, and e-bike single speed builds, offering solid value for money for the right rider.

Frequently Asked Questions

Is this crankset compatible with multi-speed drivetrains?
No. This crankset and chainring are intended for single speed use only and are not compatible with derailleur systems.

What bottom bracket interface does it use?
The crankset uses a square taper spindle interface, so confirm your bottom bracket type before purchasing.

Does the package include chainring bolts?
Yes. The package includes one crankset, one single speed chainring, and four chainring bolts for installation.