After "acquiring" a copy last week of TT3 - I got a copy of TT5 this week. Installed fine - one or two problettes. It is quite good although the software is not much better than TT3, but the maps are more upto date and the Camera database function is built in - don't need CheckPOInt 2/3.

Says my speedo is 5 mph High!

After "acquiring" a copy last week of TT3 - I got a copy of TT5 this week. Installed fine - one or two problettes. It is quite good although the software is not much better than TT3' date=' but the maps are more upto date and the Camera database function is built in - don't need CheckPOInt 2/3.

Says my speedo is 5 mph High![/quote']

My tom tom reports my speed around 5 miles an hour less depending on how fast I am going. The gap gets bigger the faster I go.

Hi,

Mine reads as follows

TOM TOM SPEEDO

30 33

40 44

50 55

60 65

70 75

I measured TOM TOM against a calibrated speedo and it was either dead on or 1mph slow.

Regards

I noticed similar with mine too - Tom Tom seems to show about 10% slower. Interesting to see that the Tom Tom was spot on - but then it should be given the satelite technology involved. That means I can go 10% faster (at least that's what I told SWMBO).

Same here, speedo is about 10% high in the octy. in my mondeo the difference is much smaller.

I thought all speedos are set to overstate your speed, because they don't typically get re-calibrated after leaving the factory so they build in a margin of error to prevent people unwittingly speeding (and then recovering the cost of the fine from the car manufacturer)

Mine is the same with TOM TOM and my Road angel. About 10% ish

I thought all speedos are set to overstate your speed, because they don't typically get re-calibrated after leaving the factory so they build in a margin of error to prevent people unwittingly speeding (and then recovering the cost of the fine from the car manufacturer)

I think the problem may be that the speedo measures the rpm of the wheels, but the distance they actually travel for each revolution depends upon the diameter, which depends on wheel size and tyre type and make. I suspect it is probably calibrated for the largest likely wheel and tyre diameter combination