The isolation method: find the source before acting
A noise on a bike can come from anywhere. The frame, seatpost, bottom bracket, headset, wheels — everything is connected and vibrations travel. Before taking anything apart, you need to isolate the source.
Systematic 4-step method:
- Standing vs seated. If the noise disappears when you stand up, it's the saddle/seatpost area. If it only appears when standing, it's the headset or handlebars
- Pedaling vs coasting. If the noise is linked to pedaling, it's the drivetrain (BB, chain, pulleys, cassette). If it persists when coasting, it's a bearing, brake, or loose part
- Left stroke vs right stroke. If the noise occurs only on each left pedal stroke, it's the left crank arm, left pedal, or left-side bearing
- Under load vs unloaded. Put the bike on a stand and spin the wheels, engage the brakes, move the headset. Some noises only appear under load (rider weight)
Rhythmic clicking (click-click-click)
The most common and most annoying noise. It's synchronized with pedaling.
Causes ranked by frequency (most to least likely):
- Loose pedals — Torque: 35-40 Nm. Grease the threads. The left pedal has reverse threading (tightens counter-clockwise)
- Bottom bracket axle — BSA: 35-50 Nm. Check that the cups aren't loose. Apply threadlocker (Loctite 243) if recurring
- Loose crank arms — Fixing bolt torque: 12-14 Nm (Shimano Hollowtech II left arm). If the crank has play, it clicks every revolution
- Seatpost — Grease the tube (aluminum) or use carbon assembly paste (carbon). Clamp torque: 5-7 Nm. The click occurs when you load the saddle
- Headset — Play in the headset bearings. Brake, rock the bike back and forth: if there's play, you'll feel it in the handlebars
Tip: apply grease to all contact interfaces (pedals, axle, seatpost, saddle clamp) and retighten everything to spec. If the noise persists, move to the next step.
Continuous grinding
A constant grinding sound, often worse in wet weather.
Common causes:
- Dry chain — The #1 cause. Lubricate your chain regularly (every 200-300 km on road, every ride on MTB)
- Worn jockey wheels — Dry bearings or worn teeth. Replace them (see our dedicated article)
- End-of-life BB bearings — A BSA that grinds under load. Replacement needed
- Brake rub — Warped rotor or misaligned caliper. Check by spinning the wheel freely
Creaking under effort
A deep, dull noise, especially when out of the saddle or accelerating hard.
Common causes:
- Dry seatpost in frame — Especially on carbon frames: the carbon assembly paste wears out. Clean and reapply
- Saddle clamp — The saddle rail moving in the cradle. Torque: 8-14 Nm depending on the cradle. Grease the contact points
- Cracked carbon frame — Rare but serious. Visually inspect stress areas: BB shell, seat tube, junctions. Creaking that progressively worsens is a warning sign
- Rear wheel — Spokes crossing and rubbing each other. A touch of grease or threadlocker on the crossings fixes it
