Speedometer Accuracy

[Wt_know]

The model of my car comes with 16" and 17" rim/tyre. How do I find out whether the speedometer is factory calibrated for 16" or 17" rim/tyre ?

 

If the standard package comes with 16" and I selected the sport version which is upsized to 17" .... my speedometer and milleage is out ?

 

Thanks

Edited February 26, 2007 by Wt_know

[Falc]

Precisely. Same car may have different rim size for standard package in different country. So the speedo and mile meter are not meant to be 100% accurate, 1-3% "error" is acceptable.

[Wt_know]

okay. if i upgrade my rim/tyre to 18" the discrepancy will be even greater.

 

can i use this as an excuse for travelling exceed speed limit ? ... just kidding

[Falc]

Not like that one. Overall size still include the tyre portion mah. So if youo opt for thinner tyre on 18in, overall diameter may be smaller than your original 17in combo. That's why your tyre profile must be chosen to minimize the difference.

 

Nonetheless, I purposely chose to increase my overall diameter by 2-3% when i upgrade my rims earlier as i wanted the extra rubber for comfort.