wsup guyz, i was jus wonderin that when i get 18 inch rims would the speedometer be off and read slower mph due to more surface contact of the tires???? if so can it be corrected???????

 

Interesting questions there.

Changing your rims or tyre sizes can make a difference to the speed shown to your 'real' road speed but not because you may have more surface contact. The difference is down to something called "rolling radius".

Check this link, it explains a lot about tyres & rims.

http://www.geocities.com/chrislonghurst/tyre_bible.html

Changing stock size rims up to 18" doesn't automatically mean you will have more surface contact on the tyre. The tyre profile and width make a lot of difference. The lower the profile 'number' the less longitudanal tyre to surface contact, the greater the width the more lateral tyre to surface contact.

So for example; if you changed from a 16x60x8 to an 18x40x8, the 16 would probably have more surface contact than the 18. If you changed the 16 to an 18x40x10, then the 18 would probably have more contact.

Tyres and rims can be very complicated or very easy. Stay as close to the same 'rolling radius' as the stock set up and you will never notice the difference.

Hope this helps.