Hello all,
I did do a search but I was unable to find the information I was looking for.

I recently purchased a 2008 G35X sedan. it has stock 17" wheels on it but the tires are worn. I am considering replacing the wheels with 18" rims. My question to you is;
1) If I go to a larger wheel will there be any issues with the accuracy of my speedometer and oddometer? If so is there a way to recalibrate it?
2) What size tires should I use?

Any other information would be greatly appreciated.
Take care,
Willie

 

1) There won't be any issues if you keep the overall diameter as close to stock as possible.
2) Tire sizes depend on the width of the wheels and how much rubber you want to run.

The stock 18's are 18x7.5" and 18x8.5" with 225/50/18 and 245/45/18 tires.
You could do a search and see what others have run. There aren't too many people that upgrade to just 18's, usually people go for 19's or 20's when going aftermarket.
If you get the stock Sport 18's then you can just stick with the stock tire sizes.

If you're going aftermarket then post up the specs of the wheels you're looking to get to get some recommendations on tire sizes.