On 16 Oct 2009, at 16:58, Brian on Harnser wrote: > roger_millin wrote on 16/10/2009 : >> Brian wrote: >>> I bought a Tomtom and this shows that my speedo reeds 3mph high >>> from 30 >>> all through the range. >> >> Because the legislation on motor manufacturers enforces speedo >> calibration >> that is allowed plus 10% but minus 0% (IIRC) so the manufacturers >> tend to err >> on the upper side to ensure that their customers don't >> inadvertently exceed >> the speed limits. In your case 3mph in 30mph is spot on the 10%. >> Roger >> > But 3 MPH at 70 isn't. I've never been any faster than that
Yeah but it is "within" the +10% tolerance. I'd always assumed a 10% tolerance would be linear up and down the speed range, which it probably would be with a mechanical speedo. I guess with the electrickery they can do anything. Beeky
