Renold - Troubleshooting Guide: Fretting Corrosion

What is Fretting Corrosion?

Fretting corrosion is a type of wear that occurs when two metal surfaces rub together. For example, this can happen with your motorbike chain if not properly lubricated. If left unchecked, fretting corrosion can cause severe damage. 

Usually, it will occur at contact points with some vibration, e.g., at the connecting pins between links or as the chain moves around the sprockets. This constant movement causes the metal surfaces to start wearing away at each other. Over time, this can lead to severe problems like cracks or even a complete failure of the chain.

What Does Fretting Corrosion Look Like?

It can manifest itself in various ways, depending on the severity of the corrosion. In its mildest form, fretting corrosion may appear as small pits or scratches on the surface of the chain. In more severe cases, it can cause deep pitting, flaking, or even total failure of the metal surface.

It's often most noticeable at points of contact between two metal surfaces. This is because this type of corrosion occurs when small metal particles are worn away from one surface and deposited on the other. As these particles accumulate, they can create a rough, uneven surface susceptible to further corrosion.

While it can occur on any bike, it is most commonly seen in motorcycles ridden in wet or humid conditions. It appears as a fine powdery deposit on the surface of the metal and can eventually lead to the pitting and flaking of the metal. In extreme cases, it can even cause structural damage to other areas of the bike. 

In addition to your motorbikes chain, it is most commonly seen on the derailleurs, and brake callipers, so keep an eye on those as well as your chain. 

If you see any of these signs, it's essential to have it repaired as soon as possible to avoid further damage.

How Can I Prevent Fretting Corrosion from Happening?

Regular, standard motorbike maintenance will take care of most issues of this type. Ensure metal surfaces are clean and debris-free before they come into contact with each other. In addition, using lubricants or coatings on your chain can help reduce the amount of friction and wear that leads to fretting corrosion. 

Make sure to regularly lube all the contact points on your chain and associated components. If you ride in wet or muddy conditions, you should also clean and lube your bike more often to prevent corrosion.

Here is a list of ways to prevent Fretting Corrosion;

  • Use a high-quality bike lubricant on all friction points, including the chain and gears.
  • Wipe down your bike after every ride to remove grime and dirt.
  • Store your bike in a cool, dry place.
  • Inspect your bike regularly for signs of corrosion and take action to address any problems immediately.

What Do I Do if Fretting Corrosion Occurs?

If you notice any corrosion on your bike, it's crucial to take action to prevent the problem from getting worse. The first step is to clean the affected area with mild soap and water. Once the area is clean, you can apply a thin layer of lubricant to help protect the metal from further corrosion. If the problem persists, you may need to replace the affected parts.

What are the Consequences of Fretting Corrosion?

  • Damage to the surface of the metal cause pits, grooves, and other types of surface damage.
  • Degradation of metal components is more susceptible to other failure modes, such as rust.
  • Corrosion products can accumulate in the contact area and cause problems with their fit or function, resulting in a loss of power, handling, and a less comfortable ride.
  • In extreme cases, a total failure of the chain.

As can be seen, it can be a severe problem that causes significant damage to metal surfaces. Preventing via regular maintenance is, therefore, the best approach.