A grimy crankset spoils the ride: creaks appear, pedalling feels draggy, and dirt mixed with lubricant turns into an abrasive paste that wears chainrings and chain faster. Traditionally the cranks come off to reach the axle, but for routine care that is not necessary.
You can thoroughly clean the cranks, chainrings, bolts and the area around the bottom bracket on the bike in 15-20 minutes.
What you will need
Important: Do not aim a pressure washer at the bottom bracket or hubs, or you will flush grease out of the bearings. Keep all products away from brake rotors and pads.
Step 1
Rinse off loose dirt
Lightly rinse the crankset with clean water to remove dust, sand and dried mud. This matters: scrubbing straight away drags hard particles across the finish of the cranks and chainrings.
Inspect the parts while you are at it. If the chainring teeth are clearly pointed or a crank arm is damaged, the crankset is due for replacement.
Step 2
Break down greasy grime
Where black deposits of lubricant and dirt have built up, spray WD-40 Multi-Use generously over the chainrings, cranks and bottom bracket area. For gaps between the rings and around the axle use WD-40 Smart Straw with the thin straw. Give it 2-3 minutes to soften the deposits.
Step 3
Scrub and dry
Brush the chainring teeth on both sides, the inside of the cranks and around the bottom bracket cups. Slowly backpedal so you cover the full circle.
Rinse with gentle water pressure and dry immediately with microfibre. Do not leave moisture in the gaps, especially if the bike is stored somewhere cool.
Step 4
Protect and lubricate
Once everything is dry, apply a little WD-40 Specialist White Lithium Grease to the chainring bolts, exposed axle parts and friction points using the straw. It leaves a protective film against moisture and corrosion, which matters most if you often ride in rain and mud. Wipe off the excess with a dry cloth so dust does not stick.
Step 5
Check the crankset runs smoothly
Turn the pedals by hand: the cranks should spin freely with no catching or odd noises. Rock the cranks sideways: noticeable play or creaking after cleaning means the bottom bracket needs servicing separately.
Tip: Lubricate the chain straight after cleaning the crankset: a clean crankset paired with a dirty chain will be filthy again within a few dozen kilometres.
What next
Repeat this clean every 3-4 months if you ride regularly, after every muddy or wet ride, and before and after winter storage. To protect other metal parts from damp, use 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.
More guides in «How to use».