Coming down the M1 last week with the GPS on my PDA locked onto nine sats the GPS was showing dead on 70 the speedo varied from 68 - 76, allowing for the inaccuracy of the speedo, which is more accurate????

Assuming that you were driving in a straight line and on the level, the difference between the 2 readings should not have fluctuated by more than a couple of mph. The GPS reading is more likely to be correct than the speedo. If checking for accuracy, it does help to have cruise control engaged to keep the selected speed constant.

whilst the GPS is more accurate than the speedo, what is the refresh time for the GPS

my hand held Ipaq GPS shows the speed as it was 2 seconds ago not as it is now whilst the laptop GPS shows half second ago

Denis has it right, set the cruise control to say 70 and see what the gps tells you over a length of time

I have found that on my Discovery the speedo is out by 4mph + (i.e, speedo will show 70 whilst gps shows 66) when I get my Fabia I will do the same test on that and see what the difference is

If your gps reciever cannot deal with altitude and changes in altidude like going up/down hill the speed will change slightly, the reason is to go up/down hill you need to cover more road distance to cover the same horizontal difference. The speedo will therefore read the same, but the GPS will show a lower speed than if the road were totally flat.

Coming down the M1 last week with the GPS on my PDA locked onto nine sats the GPS was showing dead on 70 the speedo varied from 68 - 76, allowing for the inaccuracy of the speedo, which is more accurate????

thats because your getting on a bit now and your having trouble keeping a constant speed,what with your hat dropping in front of your eyes all the time!!!! LOL

If your gps reciever cannot deal with altitude and changes in altidude like going up/down hill the speed will change slightly, the reason is to go up/down hill you need to cover more road distance to cover the same horizontal difference. The speedo will therefore read the same, but the GPS will show a lower speed than if the road were totally flat.

If you consider this trigonometrically you'll realise that hills don't make much of a difference unless they're really steep...

Coming down the M1 last week with the GPS on my PDA locked onto nine sats the GPS was showing dead on 70 the speedo varied from 68 - 76, allowing for the inaccuracy of the speedo, which is more accurate????

I can't see what happened there - but if what you're saying is true then your speedo or GPS is faulty. I wouldn't expect a fluctuation of more than +/- 1 mph

thats because your getting on a bit now and your having trouble keeping a constant speed,what with your hat dropping in front of your eyes all the time!!!! LOL

Alex (The LPG kid), when I finally peg it, you will be really upset as you will have to find someone else to stalk on the forum.

What ever happened to "Help the Aged" ?????????????????

When are you going to do my PDA for me ?????????

Does VAG COM give reports of accurate speed, like a GPS would? :confused:

If it does the 0-60s etc, I assume its measuring the speed properly, not as per the dashpod?

According to my GPS, when i'm doing an indicated 75mph on the speedo i'm actually doing 71mph or so. But when the speedo says 95mph so does the GPS.

I was under the impression that all speedometers read higher than what you are actually doing.

I was under the impression that all speedometers read higher than what you are actually doing.

Not necessarily - but they are not permitted to under-read. The ideal would be a speedo which is calibrated and accurate - like the ones police traffic cars have.