Speedo Calibration

[chrisf70]

I let my attention slip on a dual carriageway and possibly went past a forward facing Truvelo camera at what my speedo said was 78mph, I quickly asked my wife to get out the sat nav so that I could check what speed the car was actually doing compared to the speedo.

The results were quite interesting, at 60 on the speedo the sat nav is showing 54mph, at 70 on the speedo the sat nav is showing 63mph, and on a 'private test road the speedo' is showing 80 and the sat nav reads 72mph.

The error seems quite high, my wife's old StreetKa was out by a small margin, and the VW I just got rid of was spot on.

Has anyone else looked at this, are any of yours out by a long way?

[steve1975l]

Different wheels?

[chrisf70]

Standard wheels for a Design nothing modified on the car. I know speedos are generally out quite a bit, but it just seems a bit high. Glad it is though as I might be alright on the speed camera.

[steve1975l]

I will try mine but I have noticed it under reads on my previous cars.

[parapaul]

Mine read under on the vectra - but not that much, it was less than 10%. If the speedo said I was doing 65, the sat nav said 60.

[67688c]

On current veccie and previous 2 cars I've noticed that the Satnav tends to read about 3mph slower at 70 than the speedo reading.

Current car has standard VX structure wheels, the Satnav is near enough same as speedo at 30 but as speed rises the speed reads a touch low.
I assume the Sat nav is the most accurate... The speed differences on yours do seem quite excessive, have the wheels been changed to a larger size.

Those later Truvelo cams BTW according to the Pocketgpsworld tend to be set to a lower tolerance than the older Gatso cams. Hope you dont end up with 3 points.
My son mentioned at the weekend he had been done again for doing 37 in a 30 near Kidderminster, but he got his wife to take the points, as she only has 3 on her licence and they come off shortly... silly really... he'll learn eventually, but it is easy done.

Think we ALL need those speed awareness courses... Mind you, it seems that few councils are offering these now instead of the fixed penalties, as I know a couple of people who were recently caught in a 30 limit area and were done for doing less than 35 but were not offered the awareness course.

[MalcGSI]

My son mentioned at the weekend he had been done again for doing 37 in a 30 near Kidderminster, but he got his wife to take the points, as she only has 3 on her licence and they come off shortly... silly really... he'll learn eventually, but it is easy done.

Careful what you post.

[67688c]

Careful what you post.

Good point... or should that be points..lol

Server used to allow 15 mins before time ran out for editing messages, but I dont hink its that long now, as I did try to edit it after your posting, but it was too late to change it.

[Hideous]

Good point... or should that be points..lol

Server used to allow 15 mins before time ran out for editing messages, but I dont hink its that long now, as I did try to edit it after your posting, but it was too late to change it.

PM one of the mods - I'm sure they'll be happy to remove it for you when they sign on

[Big Sig]

Its about the same as mine