How to test a mouse scroll wheel

A fair wheel check takes about two minutes: one setup pass, one steady run per direction you use, and — if you change anything — a repeated run under identical settings. Everything below runs on the main scroll wheel tester.

The repeatable procedure: choose, calibrate, collect, compare. Each box maps to a step below.

1. Set up (30 seconds)

Close or ignore pages that scroll on their own. Keep this tab visible — hidden tabs pause the timer.
Choose the input type honestly: standard wheel, or touchpad / free-spin for coasting hardware.
Pick one direction and 15 seconds. Longer windows beat repeated short ones.

2. Calibrate, then keep it steady

Press Start Test and click into the pad so it holds focus.
Make 3 slow movements in the requested direction to start the timer.
Keep one speed and one direction until the timer ends. Do not correct mid-run — corrections count as opposite-direction input because the tool cannot tell intent.

3. Read the result once, then repeat

Read the observation card first, then check sample quality (at least 8 events, full duration covered) and validity (no interruptions, single unit). Then run the identical setup once more. A pattern that repeats is worth more than any single verdict; a sample under 8 events simply means “too few to interpret” — run the full duration again.

4. Compare before and after fairly

Open the compare page: save the first guided run as Run A, change exactly one condition (port, browser, extensions, OS setting, or cleaning step), and record Run B with the same phases. Mismatched settings trigger a comparability warning. A difference describes browser-observed input only.