Is my satnav speed indicator more accurate than my cars speedo?There is a discrepency of about 3 mph.?

Answer 1

I run a Speedometer Business and use a gps system to calibrate and check vehicles for inaccuracy on a daily basis. The gps system is dead on the money as long as i am driving steady without increases or decreases in speed.

New vehicles do not come Inaccurate from the factory. They strive to make vehicles accurate in all ways. But they ARE ALLOWED up to 6% inaccuracy. That is only 3 mph off at 50 mph.

So the answer is that your satnav is probably more accurate than your car's speedometer.

I hope this helps....Good Luck!

Answer 2

The satnav reading is more accurate when you are driving on a level road but will be less accurate on a steep hill.
you should only compare therefore when driving with no gradient. The satnav should prove that your car's speedo is between .5% and 5% too high in most cars. Manufacturers aren't allowed to make them too low.

Answer 3

Sat Nav Speed Accuracy

Answer 4

Sat Nav is nearly exactly right on a level road, and the difference when on hills is only slight.
The cars speedo has many variables to deal with from tyre wear to mass production. A cars speedo will always err on the side of caution.

Answer 5

All car speedometers have built in an error of 3% to 5% for safety reasons (ando commercial ones)

The satnav indicator is sutrly right.

Answer 6

If you have the original size tires with your car,your car speedometer will be more accurate. If you changed tire sizes and not changed the gear in your transmission then your speed will be off. The satnav I am not sure of.

Also google your model of satnav system to see if it needs any updates or not.

Answer 7

The sat nav is about as accurate as you're going to get.

I've noticed the same thing. The cars speedo is always slightly higher. I suspect that car manufacturers fix it that way so we don't all get done for speeding.

Answer 8

hi there,
the sat nav signal has to be bounced of the nearest satelite and then back to your unit so the unit will always be lazy, your car speedo isn't too acurate either, there can be as much as 10% difference in readings for some cars even car to car, with same manufacturer too

Answer 9

Yes 70mph on the sat nav 78mph on a ford mondeo, but running on new tyres which turn less times per mile than worn tyres (because they becomes smaller with wear), you can get 2/3 mph difference that way

Answer 10

We experience the same and have been advised by a reliable source that the sat nav indicator is more accurate. Hope this helps.