A chain rusts when the bike spends the winter on a balcony, stands out in the rain or is put away wet after muddy autumn rides. A rusty chain runs stiffly, crunches, shifts poorly and wears out the chainrings and cassette faster.
The good news is that if the chain is not stretched or bent, it can be restored. Here is how to remove rust quickly with WD-40 and a brush, and how to soak a badly rusted chain.
What you will need
Important: Keep all products away from brake pads, discs, rims and tyres by covering them with a cloth. Work outdoors or in a well ventilated room.
Step 1
Prepare the space and the bike
Choose a flat, clear area with room to work all around the bike. Move fabrics and rugs away and lay down cardboard or an old cloth. Put the bike in a stand or turn it upside down onto the saddle and bars.
Step 2
Check the chain condition
Light surface rust comes off easily. But if links are seized, or the chain is clearly stretched or bent, cleaning will not save it and it is better replaced to protect the cassette. A simple chain checker shows stretch in seconds.
Step 3
Remove rust with WD-40 and a brush
Spray the rusty areas generously with WD-40 Multi-Use using the wide spray setting while turning the pedals backwards so every link gets coated. Wait about 10 minutes for it to soak under the rust. Then scrub the plates and rollers with the brush. On stubborn spots, reapply and wait another 10 minutes. The WD-40 Smart Straw lets you target the rollers precisely.
Step 4
Soak a badly rusted chain
Remove the chain with a chain tool or open the quick link. Clean off old dirt and grease first, then submerge it in a glass container of white vinegar for a few hours, or in a citric acid and water solution for a day. Then brush it, rinse it thoroughly with water and dry it straight away.
As soon as it is dry, spray the chain with WD-40 Multi-Use to drive the last moisture out of the rollers, then refit it in the same direction as before.
Step 5
Lubricate the chain
WD-40 Multi-Use cleans and displaces moisture, but a chain needs a dedicated lubricant for everyday riding. Put a cloth underneath, apply WD-40 Specialist Bike Chain Lube to the inside of the chain while slowly backpedalling, let it soak in for a few minutes and wipe the excess off the outer plates.
Tip: After every ride in the rain or on wet roads that have been salted in winter, wipe the chain and give it a quick spray of WD-40: salt and moisture are what turn it rusty within days.
What next
Clean and lube the chain roughly every 150-300 km, and more often in wet weather. Store the bike somewhere dry. The rest of the bike's metal parts can be protected from rust with WD-40 Multi-Use.
These uses come from the experience of WD-40 users in many countries. Always follow the instructions and warnings on the product label.
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