ChrisPollard Posted October 17, 2011 Report Share Posted October 17, 2011 I discovered something unusual on the highway this weekend. My EVIC speed display, which is really the one I use while driving due to the placement of the actual speedometer, and the needle on the speedo are in sync with each other until I get above 90km/h (56mph). By 95km/h on the EVIC, the needle is around 96. by 100km/h on the EVIC, the needle is around 103. By around 105km/h, the needle is close to 109/110! So my question is .... anybody know which one should be taken as correct? Anyone else ever experience this? I would have assumed it wasn't something that would be 'open to interpretation' depending on which gauge you view. My concern is that I have a 1500km road trip coming up next weekend on the Interstates - and I'm not sure which speed I will be going by the time I get up to 70mph on the EVIC! Or the speedometer itself! Obviously a concern I'm going to have to take to my dealer, just wondering if anyone else has experienced it. Short of seeing if my wife can pull a favour with some of the officers she works with and get them to tail me with a radar gun, I'm not sure how to be sure which is right. I haven't had a speeding ticket since 1998, and I'd like to keep it that way. (Not that I haven't had a couple of warnings since then ... but no tickets.) Quote Link to comment Share on other sites More sharing options...
SaskGuy Posted October 17, 2011 Report Share Posted October 17, 2011 If you have nav built in ot a portable nav, just compare to that... They should be quite accurate. Quote Link to comment Share on other sites More sharing options...
ChrisPollard Posted October 17, 2011 Author Report Share Posted October 17, 2011 Never thought of that one! I have GPS in my phone ... guess I'll see if an can find an app that will give me real time speed data and see how that goes. Thanks for the suggestion! Quote Link to comment Share on other sites More sharing options...
drb227 Posted October 17, 2011 Report Share Posted October 17, 2011 I've compared the speed displayed on the 8.4N nav to my speedo and it is usually out by 1 kph but not more than that. Speedos will never be 100% accurate, unless they are certified like on a police car. I would trust the speed display on the nav screen. Quote Link to comment Share on other sites More sharing options...
bramfrank Posted October 18, 2011 Report Share Posted October 18, 2011 The Evic will be the correct one as it is a digital device. The speedo is mechanical. However neither is truly accurate because the tire diameter is affected by wear and air pressure differences. GPS tends to be very accurate over the long run, but at any individual point in time may well be very inaccurate - and GPS-based odometers are completely off the wall because of an effect called aliasing - since GPS provides one position sample every second, it tends to 'cut the corners. GPS units can clock mileage when the vehicle is standing still due to atmospherics and such - at least we no longer have SA to contend with. If you try to use a portable NAV's tracklog (the factory one is (I believe) not accessible) there will be a real differential between what the odometer reads and the GPS reports. Quote Link to comment Share on other sites More sharing options...
ChrisPollard Posted October 18, 2011 Author Report Share Posted October 18, 2011 Well, after finding an Android app for my phone, I took a quick road trip tonight. I set the cruise on the highway at various speeds between 90 and 105km/h, and my wife gave me the readings from the GPS on my phone (which showed accurate around town). The EVIC has it. Matched the GPS speeds within fractions of a km/h at all speeds. Now I know ... just ignore the big dial. LOL Thanks for the suggestion SaskGuy - using GPS to check it would have been the last thing I'd have thought of. Quote Link to comment Share on other sites More sharing options...
Armendegga Posted October 22, 2011 Report Share Posted October 22, 2011 I've noticed the EVIC speed and the needle speed are different as well. I've actually noticed this in the 60s and 70s as well (KM/H) Quote Link to comment Share on other sites More sharing options...
Powdered Toast Man Posted October 23, 2011 Report Share Posted October 23, 2011 I rarely rely on the analog spedo anyway because the marks are so small and the needle is so large that it's difficult to read accurately. Why the entire second half of the speedometer is taken up by speeds that will never be used is beyond me (anyone planning to go 240 km/h?). Quote Link to comment Share on other sites More sharing options...
ChrisPollard Posted October 23, 2011 Author Report Share Posted October 23, 2011 Yeah, I've never understood 200+kph speedos either, other than possibly looking cool? I mean, who else remembers when they stopped speedos on cars around 75mph? They did that because the little crapboxes couldn't go any faster, even if you pulled out the floorboards and pushed with your feet. So there was a stigma with a 'low top speed' speedo that likely still remains. Who wants to look at a new vehicle and think it won't do more than 75mph? I agree - that big sweep could be put to far better use. The dealership did a re-calibration on my speedo. It's still not quite right, but now it's only about 3km/h out at 120-130km/h and fairly accurate through 100km/h. At those speeds at home, if I'm traveling that, I'm not worried about 3km/h on my ticket anyway. LOL Quote Link to comment Share on other sites More sharing options...
tstone Posted December 6, 2011 Report Share Posted December 6, 2011 I rarely rely on the analog spedo anyway because the marks are so small and the needle is so large that it's difficult to read accurately. Why the entire second half of the speedometer is taken up by speeds that will never be used is beyond me (anyone planning to go 240 km/h?). ^^ This. And the other thing I noticed is you're viewing the analog speedo at an angle from the driver seat, since it sits to the right. If you were able to look at it dead center, it will be pretty accurate. At least, that's how mine is. Of course, in the US the speedos only go to 120 mph/ 190 kph which might make it more accurate. Quote Link to comment Share on other sites More sharing options...
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