Bigger Wheels

[Jeffro]

If my son puts bigger wheels on his car i.e. 16"instead of 14" Will this affect the speedometer?

[Simon R]

This will depend on wether the circumference of the tyre is different. If a low profile tyre is used and the circumference of the tyre remains the same the speedo will not be affected.If the circumference of the tyres put on is larger than the original ones the speedo will read lower than the actual speed. i.e if the speedo reads 30mph you could be going faster. Hope this helps...

[twiglet4frog]

also the mileometer will be out too, so u may think u have done 20 miles but maybe only done 19, that sort of thing. Although that is good for selling the car cos u can burn up the roads and it looks like u have driven a lot less lol

[Skids]

Generally, when you put bigger wheels on you alter the profile of the tyre to suit so that the overall diameter remains the same, as Simon R mentioned.  But a perfect match is hardly ever achieved.  The new overall diameter is usually within �18mm of the original diameter.  This difference in diameters has a negligible effect on the speedometer and milometer.

[snapdharlich]

... but it still looks cool!