will bigger tires mess up the speedo?

[irjoshy]

i did a search for this topic, but found nothing. anyways, i'm thinkin about getting some 17 inch wheels for my talon, but my father insists that if i get bigger wheels that it will mess up the speedometer.

is this true?

 

[wastefuldreamer]

barely if it does. But 17"s are going to have a smaller hieght tire on them. Opposed to the 16's

 

[irjoshy]

thanks

 

[wret]

Try this link for info on tire sizing.

http://www.miata.net/garage/tirecalc.html

Do a search on “plus sizing” and you’ll get more info than you need. The whole idea is to get a larger rim matched with a lower profile tire with the same overall diameter as your stock tire. It’s ok to be off one or two percent but a large difference in diameters will mess up your speedo.

http://www.tirerack.com has a feature built into the web site that allows you to enter your stock size and then suggests an alternate size for larger wheels.

If you are shopping for larger wheels there are a couple other fitment issues you should educate yourself on; offset and width. These have been discussed a great deal in the forums here.

Happy plus sizing.

 

[awd4g63]

Hell, your factory speedo isn't the most accurate thing in the world anyway

 

[Eclipse96Ryder]

heh heh, my gauges are messed up anyways. I got some indiglos on ebay and the gauges dont line up with the stock ones anyways. I just put bigger rims on too, my speedo could be seriously messed up

 

[Defiant]

The speedo will only care about the radius from the center of the axle spindle to the middle of the contact patch. Whether that distance is 5% tire and 95% wheel or 20% tires and 80% wheel won't matter.