Speed limits in AD

[Melfi]

Smiling to the camera, unfortunately, is for nothing. I have saved all my speeding photos and you can't see my face.
Which probably means that it was Caprihorse driving my car or something of the sort... ;-)

[Abu Jimmy]

[quote=caprihorse;17271]GPS speed is the most reliable value, as what you can see on your speedometer depends also on the size of the tyres fitted to your car. Normally manufacturer calculates speed based on the size of the tyres originally installed, e.g. between rims 16" or 17". The diameter of the wheel is calculated as 2xPIxr, so between both the difference is 2.3%. Now adding inaccuracy class for speedometer given by manufacturer of 10%, in the worst scenario, between the different cars, the maximum error could be around 15%.

The best way is to calculate the time between km poles on the highway by stopwatch [accuracy in ms] at constant speed for several kilometers, e.g 150 km/h and use the famous formula, v = distance / time [v=s/t] to compare your calculated results, with what is showing actually your speedometer.

And don't forget to smile, when doing this test. When something flashes around, they are not paparazzi :036:, but serious professional photographers.[/quote]


After changing the tires with bigger ones , you can ask the agency or any other authorized garage to re caliber ( re adjust ) the speedometer , it will take only minutes ( they will connect a computer device and enter the new tires size ) , and this is only possible if your car is equipped with ABS system . otherwise you can compare your speedometer reading with the GPS speed reading and you will figure the difference and memorize it . in my case , the Cherokee is equipped with 32"X11.5"X15 tires , and when i drive at exactly 100 km on speedometer , the GPS reads 109 km . ( or you can try Capri formula if you have time , stopwatch , calculator , personal assistant , secretary ...etc. ) :011: ....

[Darshan]

I think wasif's formula of +18 at 120kmph is the right one for an FJ, that is exactly what i have been doing (never had the guts or money to find out if that can be extended)

But pls dont take it that the speedo error is +18. Most Jap cars have a speedo error of 10kmph at 100kmph on the happy side (makes you feel like you are doing speeds more than you are actually doing) and that will increase propotionaly as you increase speed. It will decrease propotionally as you decrease speed as well. So on roads which has a speed limit of 120, i drive at 148. This takes care of the speedo error and the tolerance that the cameras are set to.

Having said this, i usually just try to stick to what the speedometer tells me, so that i am well within safe speeds and moreover going faster by 10km per hr will only save me negligibile amount of time, especially on trips shorter than 60 kms.

[Jeff]

[quote=Darshan;17295].... moreover going faster by 10km per hr will only save me negligibile amount of time, especially on trips shorter than 60 kms.[/quote]

I wish more city drivers understood this.

[strawb]

smile this way

[img]http://i42.servimg.com/u/f42/14/62/86/87/strawb10.jpg[/img]

[Wasif Ahmed]

LOL....in Abu Dhabi you would have to run around and smile as the cameras get the rear of the car and not the front ! Just so your wife doesnt find out who yiou were driving with when you got the picture taken !

[Darshan]

[quote=Wasif Ahmed;17379]Just so your wife doesnt find out who yiou were driving with when you got the picture taken ![/quote]

Phew!! That is a relief! :011:

[Wasif Ahmed]

[quote=Darshan;17387]Phew!! That is a relief! :011:[/quote]

We try to be considerate !