How to Fix a Rusted Bike Chain

Overview

A rusted chain can fail and is unsafe. This guide covers cleaning and restoring a rusted bike chain.

Step-by-Step Fix

1. First, you'll need to remove the chain from your bike; locate the master link (often identifiable by a slightly different pin or a C-clip) or use a chain tool to push out a pin. Carefully open the master link or push the pin out to detach the chain completely from the sprockets and derailleur, ensuring you keep track of any small parts like the master link clip.
2. Next, immerse the detached chain fully in a suitable degreaser solution, such as a bike-specific degreaser or even diluted washing-up liquid, ensuring every link is submerged to break down existing grime and old lubricant. Let the chain soak for at least 10-15 minutes, or longer for very grimy chains, and swirl it occasionally to help dislodge stubborn dirt before inspecting if the heaviest grease has started to loosen.
3. Once the degreaser has worked, take a stiff wire brush or a dedicated chain cleaning brush and scrub vigorously at all sides of each link, paying particular attention to areas with visible rust. Work systematically along the entire length of the chain, checking that rust flakes are being dislodged and the metal beneath is becoming more visible, which indicates effective rust removal.
4. After brushing, thoroughly rinse the chain under running water to wash away all degreaser, dislodged dirt, and rust particles, ensuring the water runs clear from the chain. Immediately after rinsing, use a clean, dry cloth to wipe the chain down, then hang it up or lay it flat to air dry completely, checking that there is no moisture left within the links before proceeding, as any water will lead to new rust.
5. With the chain fully dry, apply a high-quality bicycle chain lubricant; carefully squeeze a small drop onto each individual roller, ensuring the lubricant penetrates into the pin and roller interface. Rotate the chain slowly through your fingers to work the lubricant into every part of each link, then wipe off any excess lubricant from the outside surfaces to prevent dirt attraction.
6. Finally, reinstall the lubricated chain onto your bike, making sure it is correctly threaded through the front and rear derailleurs and around the sprockets, before reconnecting it using the master link or by re-inserting the pin with your chain tool. Double-check that the chain is securely connected and runs smoothly through all gears without any stiffness or snagging before you take the bike for a test ride.

Common Symptoms & Diagnostic Resolutions

Review the common error codes and operating symptoms below to quickly identify the root cause of the fault before ordering replacement parts.

Frequently Asked Questions