Why seasonal maintenance?
A bike that gets regular use accumulates wear, dirt, and mechanical stress without you noticing. Problems creep in gradually: a derailleur that skips a gear, a brake losing power, a headset developing play. Result: one day, everything fails at once.
The solution: a full inspection at every season change. 30 to 45 minutes twice a year is enough to prevent 90% of breakdowns.
Drivetrain — the first 4 points
1. Chain wear — Use a chain checker (Park Tool CC-4 or equivalent). Beyond 0.5% elongation on 11/12-speed, or 0.75% on 9/10-speed, it needs replacing. A worn chain destroys your cassette and chainrings.
2. Sprocket condition — Look at your cassette teeth. If they're hook-shaped (asymmetric, pointed), the cassette is done. Compare with a new sprocket if you're unsure.
3. Chainring condition — Same diagnosis as sprockets. Teeth shouldn't be shark-fin shaped. On a narrow-wide chainring, check that the wide/narrow alternation is still crisp.
4. Derailleur cables and housing — Inspect the housing: cracked, crushed, rusty at the ferrules? Replace them. A frayed cable or a crushed housing end means indexing that won't hold.
Brakes — 3 critical points
5. Pad thickness — Rim brake pads: the wear indicator groove must be visible. Disc brake pads: minimum 0.5 mm of compound. Below that, you're braking metal on metal.
6. Rotor condition — Minimum thickness as specified by the manufacturer (often 1.5 mm). Check for warping by spinning the wheel: the rotor shouldn't rub intermittently.
7. Hydraulic bleed — If the lever pulls to the bar or the bite point feels spongy, it's time to bleed. Mineral oil for Shimano, DOT 5.1 for SRAM/Avid. Never mix the two.
Bearings — 3 often-forgotten points
8. Headset — Lock the front brake and push the bike back and forth. Feel a "knock-knock" in the frame? The headset has play. Tighten the compression bolt on the star nut, then the stem bolts.
9. Bottom bracket — Hold a crank arm and try to move it side to side. Play? The bearing is tired. A creaking sound while pedaling confirms the diagnosis.
10. Hubs — Take the unmounted wheel by the axle and spin it. It should rotate freely without tight spots or grinding. Also try to move the rim side to side — no play allowed.
