odo/speedo problems when changing wheel size

[zackforbing]

I hear that when you change wheel sizes (say, from 15" to 17", what I plan to do) it throws off your odometer and speedometer, making them either faster or slower (I can't remember) than true speed and mileage. is this true? are there any ways to adjust them, or fix this problem?

[termitesgraffix]

yes it changes it and you can just go to the dealership or a good mechanic with a dyno and have the speedo adjusted. problem solved... or you can just have a friend drive next to you and match your speed, tell you the speed, and then add or subtract that to your speed, then just remember to do the math when you drive haha..

[miro1118]

As long as you keep the overal diameter of the wheel (rim + tire) the same you do not need to recalibrate your speedometer. As you go with a larger rim size the height of your tire sidewall needs to decrease. Your 14 inch wheels will have 60 series tires. I think that 15 inch will require 50's and so on. Go to tire rack and bring up a wheel search for your car. As you pick different size wheels the recommended tire will appear on the left. You can also search the web for a tire conversion calculater. Be careful that your tire tread does not get too wide or it will rub the wheelwells.

Take note that when you decrease the height of the sidewall you will increase handling and decrease ride comfort.

Wider tires are also not as good in snow.

Hope that helps.