I am buying a set of 19 inch te37(8.5f, 10.5r). The problem is that the guy who is selling it has already installed the following tires:
Bridgestone potenza s-03 (245/35 f, 285/30 r)
I calculated the stagger to be -0.02 (rear being smaller than the front). My question is how will my vcd/tcs...etc be affected?

 

put simply it will be negatively affected. basically your cars computer system will think the rear tire is spinning loose cause it is turning faster than the fronts. with the way our cars are setup this would even happen if you had the same size all around but in this case, it will happen even easier. with the same tires all around some say its not that bad cause it mainly only happens when taking a turn or launching aggresively. but with stagger thats actually negative the car will think your are spinning even with normal driving. what will happen is your TCS will be turned on more frequently as well as the VDC will be activated more also.

the best way around this is to buy different rears or just drive with those features turned off.

 

I could be wrong here, but I think it depends on the ratio between the front and rear tires. I don't think .02" will cause it to malfunction, i forgot what the %age was, but you can probably squeak by on that size without the VDC going nuts. Check some of the older posts though to make sure. A lot of japanese tuners were using 30 series in the back too with 235/35/19F and 275/30/19R and seem to be okay. I stuck with 245/35/19F and 275/35/19R so the tires are as close to the 18" diameters as i could, and i haven't had any weird effects yet. I don't drive much in the rain where it would kick in, that would be the real test.

here's some numbers from a wheel ratio calcalutor.
Front's don't look too bad.

size tire, sidewall height, radius, diameter, circumference, revs per mile, and difference between the 2 tires.

this is the difference between the stock size 18 fronts and your new tire.

225/45-18 4.0 in 13.0 in 26.0 in 81.6 in 777 / mile N/A
245/35-19 3.4 in 12.9 in 25.8 in 80.9 in 783 / mile -0.8%

The rears have a higher difference. Stock 18" size vs your 19's.
245/45-18 4.3 in 13.3 in 26.7 in 83.8 in 756 / mile N/A
285/30-19 3.4 in 12.9 in 25.7 in 80.8 in 784 / mile -3.6%

this below, is the difference between your fronts and rear, which looks pretty good. The actual tires sizes you have are closer in diameter than the factory chosen 18" front and rear tires. So if the VDC is looking for a ratio beyond factory, i'd say you're well within the ratio, as the tires are very close in diameter. Unless the VDC is programed for that difference. Anyways, check on some of the older posts, the ratio was posted a while back.

245/35-19 3.4 in 12.9 in 25.8 in 80.9 in 783 / mile N/A
285/30-19 3.4 in 12.9 in 25.7 in 80.8 in 784 / mile -0.1%

here's japanese tuners ratios with 235/35 275/30
235/35-19 3.2 in 12.7 in 25.5 in 80.0 in 792 / mile N/A
275/30-19 3.2 in 12.7 in 25.5 in 80.1 in 791 / mile 0.1%


Factory front and rear
225/45-18 4.0 in 13.0 in 26.0 in 81.6 in 777 / mile N/A
245/45-18 4.3 in 13.3 in 26.7 in 83.8 in 756 / mile 2.7%

 

WoW!
that's what i call quick response!
thanks a lot for the info grifferjr ^^

one more question:
a lot of people uses the 9.5f + 10.5r combo so that the car doesn't understeer too much so in my case (8.5f + 10.5r), am i going to experience a lot of understeer (i plan to track the car soon)?

 

Probably won't feel too much of a difference with the 9.5 fronts. But you can make your car more neutral with better sway bars.

 

Can anyone plz tell me why Nissan suggests 0.5 - 0.7 stagger?

 

from what i heard the only reason for asthetic purposes only. to visually give the car an aggressive look. i have heard people try to rationalize it on a performance basis but c'mon does it really have that much affect for the even the hardest of daily drivers, doubt it. i mean if you were really an autocrosser or what have ya you could just go aftermarket and set the stagger up, no real reason to have it come from the factory that way. other than it looks cool.