When should a roller chain be replaced?

A roller chain, commonly used in various mechanical systems such as motorcycles, bicycles, industrial machinery, and more, should be replaced when it shows signs of wear or damage.

common indicators that suggest it's time to replace a roller chain

1. Excessive Chain Stretch

Roller chains gradually elongate over time due to wear on the pins and bushings.
The use of a caliper is common for measuring whether a chain has excessive elongation or wear.
If the measured elongation value is greater than 0.8% to 1.5%, it is a clear indication that the chain needs to be replaced.
Continuing to use an excessively elongated chain beyond this value can lead to poor performance, noise, vibrations, and even damage to the transmission system.

2. Visible Wear

Check for wear on the rollers, bushings, and pins.
If the roller diameter is significantly worn down or cracked, the bushings are visibly worn, or the pins are loose, it's a clear sign of chain wear and a need for replacement.

3. Corrosion

Chains exposed to moisture and corrosive environments can suffer from rust and corrosion.
Surface corrosion can often be cleaned or lubricated, but If corrosion penetrates into the chain components, it can cause the chain to jam or weaken, which may necessitate replacement.

4. Sprocket Damage

If you notice excessive sprocket wear or damage, it may indicate that the chain is also worn.
In such cases, it's advisable to replace both the chain and sprockets to ensure proper engagement and longevity.

5. Excessive Noise and Vibration

When abnormal noise and vibrations occur during chain operation, it may be a sign of chain or sprocket wear.
Replacing the chain and sprockets may help resolve these issues.

6. Frequent Breakage

If the chain frequently breaks or experiences non-smooth "binding" points, it indicates that the chain may be subjected to overloading.
It is advisable to reevaluate or calculate whether the chain's strength meets the equipment's requirements.
When necessary, replacing the chain with a higher-strength one is crucial for safety and reliability.

7. Loss of Tension (Chain Slack)

If, despite proper adjustments, chain slack is frequently observed, this may be due to wear.
Replacing the chain can help maintain the correct chain tension.

Important instruction for replacing a roller chain

Do not mix new and old chains.
It is advisable to replace both the chain and sprockets together.
This can prevent issues such as uneven wear, improper operation, and potential damage to your equipment.

Furthermore, it is crucial not to continue using the chain after it has elongated beyond 3%.
Excessive elongation can lead to that the chain does not engage the sprocket, reduced chain strength, and even chain breakage, equipment damage, or safety hazards.

Measure chain stretch regularly and replace it if it reaches this limit.
Regular maintenance and checks on your roller chains can help you spot issues early.
Also, make sure to use good-quality replacement chains, keep them well-lubricated, and ensure they're properly tensioned and aligned to make them last longer and keep your system reliable.