Chain, Sprocket & Brake Wear: A Simple Log Sheet

You don't need a workshop background to catch chain, sprocket and brake wear before it becomes a problem — you just need to actually look, on a schedule, and write down what you see. Here's the simple log I keep, and what each check is actually telling you.

⬇ Download the blank log template (CSV) →

1. Chain: check every 500–800km

Chain wear compounds — a slightly stretched chain wears the sprockets faster, which wears the new chain faster once you replace it. Catching it early saves you replacing all three at once.

Pull the chain away from the rear sprocket at its midpoint — more than a sliver of daylight between chain and sprocket teeth means it's stretching
Check for tight spots by rotating the wheel — the chain shouldn't feel noticeably tighter at any one point
Log slack measurement at the tightest point each time, so you can see the trend, not just a single reading

2. Sprockets: check whenever you check the chain

Sprocket teeth wear into a hooked or shark-fin shape as they age — this is the clearest visual sign, easier to spot than measuring the chain itself.

Look at the teeth side-on — worn teeth lean instead of standing straight
Compare front and rear sprocket wear — they rarely wear at exactly the same rate
Log a simple visual rating each check: good / early wear / replace soon

3. Brake pads: check every 1,000km or monthly

Pad material wears faster than most riders expect, especially with mixed city and highway riding.

Check remaining pad thickness through the caliper — most pads have a wear line stamped into the material
Listen for a metallic scraping sound at low speed — a sign the pad has worn down to the backing plate
Log the thinnest pad's thickness in mm, not just "looks fine" — numbers catch trends words don't

A number on a log sheet catches a trend three checks before your eyes do.

4. Brake fluid: check monthly, replace on schedule

Fluid level should sit between the min/max lines on the reservoir
Colour matters — fresh fluid is close to clear or light amber; dark, cloudy fluid means it's overdue
Log the last full fluid change date so you're not relying on memory for the service interval

A simple log format that works

You don't need software for this — a notes app entry or a page in a notebook is enough. Each entry just needs:

Date and odometer reading
Chain slack measurement (mm)
Sprocket visual rating (good / early wear / replace soon)
Thinnest brake pad reading (mm)
Brake fluid colour and level (OK / due for change)

Five minutes with the bike on its stand, once every week or two, catches almost everything before it becomes an expensive or dangerous surprise.