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I was just got new rims on my EX. I now have 17's with 205/40/17 Yokos. In the tire calc. it says that I have a diff. of 4.135.

What does this mean to me? Do I need to adjust something? If I do, how?

Thanks.

 
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The speedometer will basically read the wrong speed. That's because it calculates the speed off of how many times the wheel turns. Since the circumference of your wheel is smaller than the circumference of the stock EX wheel, then the wheel will revolve more times to get to a certain distance than the stock wheel. Now the speedometer divides the number of times the wheel spins by it's circumference to get the distance traveled per unit time. Since the ECU is programmed with the circumference of the stock wheel (or so we suppose that it's programmed and not hardwired) then it reads the wrong speed with a different wheel diameter.

Phew! Okay, so the solution is to change that number. Many other cars have that number built into their ECU. I don't know if our cars do. I think they do. That way we can put on a different size tire and change that number in the ECU and get the correct speedometer reading. Right now AEM's $1600 system does this, as well as the Jet Chip upgrade (or so I presume).

On a side note, I wonder if the ECU has different numbers for the EX wheel diameter and the LX wheel diameter? Maybe, or mayeb it doesn't? Then again, maybe that's not programmable at all and the speedometer is just a mechanical devise? Who knows?

 
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Would the dealership be able to take care of this? Do after market wheels void some aspect of the warranty?

 
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Not at all man....if they say it jacks with your warranty.....Then don't bend over, cause they're trying to fu*ck you in the azz....
But no really, it won't mess with your warranty at all...100%.

 
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[IMG]i/expressions/face-icon-small-smile.gif[/IMG] The LX and EX have the same wheel circumference. The EX has 185-65-15 tires and the LX has 185-70-14's. Stepped down in wheel size, but up one size in ratio. (65 to 70 profile)

Just trying to help!