"dixthewiz" wrote in message
Speedometer accuracy 481They can believe whatever they want, it would be foolish to buttume that this is the case and rely on it. For what it's worth, my 9-3's speedometer...
According to Statutory Instrument 2001 No. 25, The Motor Vehicles (Approval) Regulations 2001, Schedule 3 paragraph 19 headed 'speedometer',
1. The vehicle shall be fitted with a speedometer capable of indicating speed in mph at uniform intervals not exceeding 20 mph at all speeds up to the maximum speed of the vehicle and capable of being read by the driver at all times of the day or night.
2. For all true speeds up to the design speed of the vehicle, the true speed shall not exceed the indicated speed.
3. For all true speeds of between 25 mph and 70 mph (or the maximum speed if lower), the difference between the indicated speed and the true speed shall not exceed -
V-10 + 6.25 mph
Speedometer accuracy 482DervMan read what you put ? PUT ? ffs, if you're trying to communicate, try again. "if we spot a GPS unit on your...
where V = the true speed of the vehicle in mph.
This makes 20 mph speed limits a bit dodgy as the speedo doesn't have to be accurate that low and at a true 70 mph the speedo can read any thing from 70 to 83.25 mph. The accuracy is only related to the car that is tested for type approval. The rest of the production are buttumed to be the same.
However, in practice I find that the speedos on my cars over read by 1.5 and 3 mph. If the speedo says you are doing the speed limit you should be fairly confident that you aren't exceeding the limit so long as it is between 25 and 70 mph.
Ian
