Motorcycle Chain Dimensions

This guide explains how motorcycle chains are measured and categorized. You'll learn about pitch, width, roller diameter, and how to compare modern metric chains with classic British ones.

Chain Basics

A motorcycle chain is made up of several components:

• Two side plates (inner and outer)
• Rollers and bushes
• Pins/rivets that join the links
• Optional sealing rings (O‑ring or X‑ring)

Chain length is measured in pitches (the distance between the pins). Links are always in even numbers and include a clip or rivet-type joining link.

Metric Chain Dimensions

Here is a comparison of common motorcycle chain sizes with their respective pitch, internal width, and roller diameter:

British Classic vs Modern Metric Chains

Older British motorcycles used imperial chains that are measured in inches, whereas modern chains are categorized by metric measurements. These vintage bikes often rely on traditional sizing systems that predate today’s international standards. This means that although a modern chain may seem close in size, it may not always be a perfect match — especially when considering roller diameter and pitch accuracy.

Using an incorrect replacement chain can lead to poor sprocket engagement, accelerated wear, or mechanical failure. When restoring or maintaining these classic machines, it's critical to reference the correct imperial specifications or use chains specifically manufactured for vintage models.

Note: Some classic bikes (e.g. BSA Bantam or Triumph Cub) require genuine imperial chains due to roller fitment. Modern metric rollers may cause premature sprocket wear.

Converting 530 Chain to 520 for Racing

Many riders choose to convert from a 530 chain to a 520 chain setup when modifying their motorcycle for racing. This conversion reduces unsprung and rotational weight, allowing the engine to accelerate more freely and improving throttle response.

• Lighter chain and sprockets: A 520 setup is narrower and usually lighter than the stock 530, offering noticeable weight savings.
• Improved performance: The reduced mass can enhance acceleration and handling, especially in competitive settings.
• More sprocket options: 520 chains are widely used in racing, so a larger variety of performance sprockets is available.

Important considerations:

• Ensure both front and rear sprockets are also changed to 520 to match the narrower chain.
• Use a high-strength 520 chain rated for your engine’s power output — racing chains are available in different tensile strengths.
• Be aware that 520 chains may have a shorter service life than heavier-duty 530 chains, especially under extreme use.

Pros & Cons

Pros:

• Standard sizing simplifies replacements
• Available in various grades and strengths
• Compatible with sealed O/X-ring options for longevity

Cons:

• Improper matching (e.g. metric on classic) can cause damage
• Wider plates on heavy-duty chains may conflict with narrow frames

FAQs

Final Tips

Always confirm chain size, pitch, and width before ordering. If you're replacing sprockets as well, consider a complete chain and sprocket kit to ensure compatibility.