how to pick a dirt bike chain

Dirt Bike Final Drive Chain Specifications and Selection

Chain Size Designations and Terminology

Understanding chain size nomenclature. The most common chain sizes are 420, 428, 520, 525, and 530. The first digit multiplied by 1/8 inch represents the pitch (distance between pin centers). The second and third digits, divided by 80 inch, signify the roller width. For example, a 520 chain has a 5/8 inch pitch and a 1/4 inch (20/80) roller width.

Chain Types and Construction

  • Standard Chains: Basic construction, suitable for lower horsepower applications.
  • O-Ring Chains: Contain O-rings between the link plates to retain lubricant and exclude dirt and water, increasing lifespan.
  • X-Ring Chains: Utilize X-shaped rings for improved sealing compared to O-rings, further reducing friction and extending chain life.
  • Sealed Chains (O-Ring and X-Ring): Typically pre-lubricated and require less frequent maintenance than standard chains.
  • Non-Sealed Chains: Require regular cleaning and lubrication, offering lower cost but higher maintenance. Preferred by some for racing to minimize drag.

Strength Ratings and Performance Characteristics

Tensile strength and working load ratings. Higher tensile strength indicates a greater ability to withstand stress before breaking. Select a chain with a tensile strength exceeding the requirements of the motorcycle's engine power and intended usage (e.g., motocross, enduro, trail riding). Pay attention to the chain's master link type.

Sprocket Compatibility

Ensuring correct chain pitch and roller width compatibility with front and rear sprockets. Using an incompatible chain can cause rapid wear and potential damage to the sprockets and chain.

Chain Length Determination

Calculating and adjusting chain length. Most are pre-cut to a standard length. Count the number of links needed and, if required, shorten a chain by removing links using a chain breaker tool. Always refer to the motorcycle manufacturer's specifications for the correct length.

Master Link Types

  • Clip-Type Master Links: Easier to install and remove, but require careful installation (clip orientation) and regular inspection. Not generally recommended for high-performance applications.
  • Rivet-Type Master Links: More secure than clip-type, requiring a chain riveting tool for installation. Preferred for high-horsepower and demanding riding conditions.
  • Screw-Type Master Links: Reusable and easy to install/remove but not as robust as rivet type

Considerations for Riding Conditions

Chain selection based on typical riding environment (e.g., sandy, muddy, dry). O-ring and X-ring chains are highly recommended for muddy or dusty environments to protect against premature wear. Lighter chains are favored for racing where performance is paramount, while durable chains are essential for off-road adventure riding.