Aurion Speedo accuracy v's TomTom

[Adrian]

Hi,

I have noticed a difference in the speedometer reading when traveling on the freeway at 119km/hr (approx. on the speedo dial with cruse control on on a flat road), the TomTom says that I am traveling at less 110km/hr.

How accurate whould you think the TomTom is when your speed is consistant ?

Thanks in advance

Adrian

[theDefiant1]

Deja vu...

The nasty answer: drive past a few cameras and determine when they flash. They will post you a letter telling you how fast you were going. This was previously discussed with respect to Echos and Yari (plural for yarises, Rob?)

Experience answer: I too have driven at the legal speed as displayed by my GPS thingy (with my dash speed being +10km/hr), past many many police radars and laser and never had a problem.

I'm sick with a headache and sore joints. So is Sarah. I need someone to take care of me.

[qkslvr]

I'd say, because the GPS satellites rely on the accuracy of an atomic clock, the speed reading on your Tom Tom is going to be more accurate than your car's speedo.

[Aurion]

I'd say, because the GPS satellites rely on the accuracy of an atomic clock, the speed reading on your Tom Tom is going to be more accurate than your car's speedo.

What he said... Alot of the boaties that have built in speedos rely on there GPS's to test top speed, and not the boats speedo.

[jonbays]

if you are out in the open on a reasonably level road with more than 4 satelites in view then the tom tom will be way more accurate than the speedo.

Speedo's are designed to be between 0 to +4% accurate. Thats always fast never slow. So 110kmh real speed should read anywhere from 110 to 115kmh.

I will check mine and see what it says for a laugh but i will bet it reads fast too they all do.

[Adrian]

Thanks for your reply's.

As I mentioned the Speedo on the Aurion seems to read about 9% faster than the TomTom. I can Imagine that Toyota would set it to read faster for saftey and stop people getting booked. But it also gets the car in for a service at closer intervals.

It's good to have an idea of your true speed.

Thanks again

Adrian

[RoLLing BLK]

A guy at work had the same problem with his new SR5

he found out that Toyota has made there speedo readings

5km more than what your actully doing, safty thing i guess,

but he seems to think his is 10km out and is taking it back to get checked

[BanHien]

A guy at work had the same problem with his new SR5

he found out that Toyota has made there speedo readings

5km more than what your actully doing, safty thing i guess,

but he seems to think his is 10km out and is taking it back to get checked

I don't thing we can find a car, any car, which has accurated speedo reading

BH

[SuperDave]

Were the tyre pressures correct? Was the speedometer temperature 23*C +/- 5*C? That's what ADR 18/03 is based on.

Could always have it double checked on a dyno (to police car standards) since I wouldn't trust the GPS unit. Plus you will know how much power you have at the same time

[MT]

Were the tyre pressures correct? Was the speedometer temperature 23*C +/- 5*C? That's what ADR 18/03 is based on.

Could always have it double checked on a dyno (to police car standards) since I wouldn't trust the GPS unit. Plus you will know how much power you have at the same time

I agree with Dave, why would you trust the GPS system?

if your concentrating on the speedo that much who is watching the road?

[Buri_ZR6]

Were the tyre pressures correct? Was the speedometer temperature 23*C +/- 5*C? That's what ADR 18/03 is based on.

Could always have it double checked on a dyno (to police car standards) since I wouldn't trust the GPS unit. Plus you will know how much power you have at the same time

I agree with Dave, why would you trust the GPS system?

if your concentrating on the speedo that much who is watching the road?

my tyres aır pressure ıs on 35. well thats what i remember it coming at. what do guys keep it at?

[leasaunce]

my TOMTOM (on my phone) is 99% (its off around 1-2kph) accurate especially when you're cruising along the highway.

[qkslvr]

Thanks for your reply's.

As I mentioned the Speedo on the Aurion seems to read about 9% faster than the TomTom. I can Imagine that Toyota would set it to read faster for saftey and stop people getting booked. But it also gets the car in for a service at closer intervals.

tyre wear will also affect the speedo accuracy. As your tyres wear, the rolling diameter reduces which makes your speedo read faster. the difference in diameter between a new tyre and a worn one can be as much as an inch. So if you were running 215/40 17 tyres, an inch would approximately equate to an additional +4% inaccuracy.

[RoLLing BLK]

A guy at work had the same problem with his new SR5

he found out that Toyota has made there speedo readings

5km more than what your actully doing, safty thing i guess,

but he seems to think his is 10km out and is taking it back to get checked

I don't thing we can find a car, any car, which has accurated speedo reading

BH

You dont expect a brand new car to be 10km out though

[PengNZ]

The speedometer is required by laws to be a little bit less than the actual speed and also is required by law not to be too less than the actual speed. Usually European cars’ speedometers are accurate than others. 

[trentmeyer23]

46 minutes ago, PengNZ said:

The speedometer is required by laws to be a little bit less than the actual speed and also is required by law not to be too less than the actual speed. Usually European cars’ speedometers are accurate than others. 

The last post was in 2007. Please check that the dates are recent.