i have an 07 G35 X with the standard 17" wheels and 225 tires front and back. i was looking to upgrade to the factory 18" 225/50R18 (front) and 245/45R18 (back) that come on the S series (10 spoke). Would changing to these tires affect my AWD at all? Is the height of the tires need to be the same because of the AWD? Also, would the warranty be affected even though these are infiniti spec rims? I'm figuring I'm ok because these are the standard wheels/tires on the G35 XS, but wanted to cofirm. Appreciate the feedback!

 

fronts would be 26.9, rears would be 26.7

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

you will have different amounts of grip due to the wider footprint out back. how much would this be a factor, I'm not sure.

you could just go 225/50 all the way around... would make for a modest amount of tire stretch out back that might look pretty sweet.

 

I dont think the grip would be significantly different and i dont think it will affect it much.

 

A much better option would be to go with the '06 19" wheels, and you could run 245/40X19 all the way around with any issues. Those are way better looking wheels than the '04s....
Gary

 

You really need the same size tires all the way around. They don't have to be the same tire size written on the tire, but needs to be the same overal diameter. Actual tread width on the ground doesn't matter.

26.9" and 26.7" is pretty close, but even that may effect the AWD. WHen the transfer case is fully engaged, the front and rear are now 1:1 and since the tires are different diameters, something is going to have to give.

How wide are the front rims? if they are 7.5 or 8" wide, you could swap a 245/45/18 on the front so they all match

 

These may be the standard wheels on the XS but certainly are not the standard tire sizes on the XS. Not sure of the exact effect other than the fact that Infiniti recommends using the same correct size at all four corners. My thinking is that if they are the same diameter and give you the same track width that nothing bad should occur.

 

Up to about 12 mph with the snow mode on unless slipping. Without snow mode then 75 back, 25 front up to about 12 mph. If slipping then that would not be an issue. With power on the weight would shift towards the back which would tend to decrease the diameter of the back and increase the front (which is the opposite desired since the backs have a smaller diameter).

I would think that this would come down to how sensitive is the AWD electronics. There must be some leeway for tire pressure as running a little less pressure in the front with this arrangement would probably equal things out (I don't recommend it).

 

I think there would be, but how much is the question. I honestly think a Nissan engineer is needed to clarify that.

I know some GM's have had issues with their AWD when simply replacing 2 tires at a time and having the other 2 worn down.

QUick google search and i found this thread
http://www.gminsidenews.com/forums/f...raining-68760/

I know not the same AWD system. But the AWD components are rather expensive and it would be nice to get a good solid answer into how much tolerance there is in the system to overall tire diameter difference.