Can anyone tell me what kind of diffrences to speed of a vehicle can be expected when the operator has fit tyres larger than those that were on the artic unit when the tacho was calibrated.
I don’t want info on it being ilegal etc , I m just curious as to why it would be done obviosly for a bit more speed but in then great scheme of things would it make a big difference?
How much bigger?
Did it used to have low-profiles tyres on?
Don’t know how much difference without knowig the amount of increase, but there is a noticable increase of top speed (based on time, not indicated speed) when we have new tyres fitted. The indicated speed will be the same as it is related to the wheels anyway, so what shows on the tacho will also be the same. Only the actual speed will be increased, and whether or not this would be a huge difference is unlikely I would have thought.
gardun:
How much bigger?
Did it used to have low-profiles tyres on?.
Not sure to be honest gardun about the size diffs …just that I was talking to a guy who says and swears that he was flashed with a speed cam and that the location he was flashed in is one he has travelled hundreds of times in another vehicle keeping to the same speed…with no issues at 30 mph .
He seems to think that the tyres on his new unit have been switched to larger ones than were on the unit when the tacho was caliberated .
Would it mean that the speed recorded on the speedo was inacurate had the tyres been switched.? 
thecoder0:
Would it mean that the speed recorded on the speedo was inacurate had the tyres been switched.?
If they are a different size yes, but by how much depends on how much difference there is in size. I would have thought it doubtful that this would make the speed more than 10% & 2mph over the recorded speed, and this is what most speed cameras are set to.
using ■■■■■■■■■■■■ tyres for calibration then replacing them with new tyres will up your speed from 56 to 60
biggusdickusgb:
using ■■■■■■■■■■■■ tyres for calibration then replacing them with new tyres will up your speed from 56 to 60
Yes but at an indicated speed of 30 mph that will mean you’re only doing 32 mph which shouldn’be a problem.
thecoder0:
Can anyone tell me what kind of diffrences to speed of a vehicle can be expected when the operator has fit tyres larger than those that were on the artic unit when the tacho was calibrated.I don’t want info on it being ilegal etc , I m just curious as to why it would be done obviosly for a bit more speed but in then great scheme of things would it make a big difference?
Check out this thread we were discussing up till last week.
speed limits and tachos ■■?
thecoder0:
Can anyone tell me what kind of diffrences to speed of a vehicle can be expected when the operator has fit tyres larger than those that were on the artic unit when the tacho was calibrated.I don’t want info on it being ilegal etc , I m just curious as to why it would be done obviosly for a bit more speed but in then great scheme of things would it make a big difference?
You need the Distance from middle of Axle to Road in Centimeter,multiplicati it with 2 to get Diameter,with Pi (3.14),and you have in cm the distance the Wheel need by one Turn.Now,divide 90000 with that number of Centimeter and you have the number of Turns the Wheel does to do 90km/h
Now take the New wheel an do as well Rx2xpi to get the lenght of one Turn.Multiplicate it with the number of Turns the old wheel did to do 90 km/h,and you have the Centimeter that Wheel does in one Hour.Judt do 5 Nills away to get km/h
Eh?
thecoder0:
gardun:
How much bigger?
Did it used to have low-profiles tyres on?.Not sure to be honest gardun about the size diffs …just that I was talking to a guy who says and swears that he was flashed with a speed cam and that the location he was flashed in is one he has travelled hundreds of times in another vehicle keeping to the same speed…with no issues at 30 mph .
He seems to think that the tyres on his new unit have been switched to larger ones than were on the unit when the tacho was caliberated .
Would it mean that the speed recorded on the speedo was inacurate had the tyres been switched.?
Has he actually had the NIP, as cameras have a habit of randomly flashing occasionally, something to do with self calibration.
The tyre sizes would have to be massively different from stock to have any kind of major affect in speedo readings …
thecoder0:
[I was talking to a guy who says and swears that he was flashed with a speed cam and that the location he was flashed in is one he has travelled hundreds of times in another vehicle keeping to the same speed…with no issues at 30 mph .l
He wasn’t an agency driver in a Pollocks wagon was he 