speedo gear replacement?

[needmorecrap]

I want to get my wife some new rims and tires(225/40/18's) but dont want her speedo to be off. In the haynes manual it shows a vehical speed sensor with a gear, so it is like my jeep that i can replace this gear and fix it or does it need to go to the stealership and have them calibrate it? Thanks

[calreef18]

That size wheel and tire is gonna be pretty much on the money for speedometer, shouldn't really be off.

[needmorecrap]

actually it will be 4% off, so when the car says i'm doing 60 i'm really going 62.5 Its not that much of a difference but i dont want extra miles on the car.

[xavier]

wouldnt that put less miles on the car? If the speedo says your going slower than you really are, your mileage will be slighlty less than whats actually on your car. Right?

[Nyyankees3511]

Mileage wont be affected, totally different sensor.

[Jon11582]

actually it will be 4% off, so when the car says i'm doing 60 i'm really going 62.5 Its not that much of a difference but i dont want extra miles on the car.

Its actually 1.6% if its got stock 15s, slightly more with stock 16s.

At 60MPH on the speedo, youll be going 59MPH

Anything below 3% is considered negligable and does not require correction.

http://www.1010tires.com/TireSizeCalculator.asp

Stock is 205/65/15 or 205/60/16