speedo check australia

To check your speedo in Australia, pick a flat road, set cruise at an indicated 100 km/h, and compare with a decent GPS app—most cars read a touch optimistic. Under ADR 18, indicated speed must never be lower than true speed and can be higher by up to 10% + 4 km/h, which is why many dashboards show 103–108 when you’re actually doing 100. If your readings are way off, check tyre size and pressures; oversized rubber makes the speedo under-read, which isn’t legal. For something official, get a workshop or instrument specialist to do a calibrated run or roller test for rego or engineering paperwork. And no, that free phone app won’t win in court, but it’s perfect for catching a dodgy needle.