I have a performance model 350Z (18"x8"). Is there a good reason not to buy four 245/45R18 tires? That would at least allow me to rotate the tires front-rear. What would this do to the handling?
Thanks,
Mika

 

It would make the car more likely to oversteer, but exactly how much more likely is difficult to determine. Since the Z already understeers, it may not really be a problem. In fact, I was toying with the idea of using the 245/45-18 all around, but in the end I will probably go with a 245/40-18 in front and a 255/45-18 in back.

If you are unsure, you can always do the old "swap tires on rims" side-to-side rotation. That way you can use different size front and rear tires, but just reverse their orientation on the rims so you can swap the wheels from one side to the other. The front to back rotation seems better though, because after 9000 miles my front tires are about 1/2 gone, while my rears are only about 1/8 gone.

-D'oh!

 

The only possible problem I can think of is the VDC not liking the tires being the same size.

 

Another quick question. Can you change just the front two or just the rear two since they are wearing out differently?

Thanks!

 

Yes! Changing out just the front two tires (with ones of the same type and size) is possible. The same applies to the rear, if they wear out first.

There have been several other discussions on why you CANNOT go to just one size due to VDC. In short, VDC reads out the tire size differential and acts if the RPMs change. This could cause your 350Z to have drivability problems. Please do a search and I think you'll find more than my simplistic explanation.

 

So if you have a Base or Enthusiast model then this isnt a issue since thay do not have VDC?????

 

RWD! you want more patch for more power transfer!

you COULD use 4 same sized tires, but then you might as well have bought a FWD. ;P

in all seriousness, the backend would probably act more 'neutral' than say, understeer like D'Oh said. not as much, contact with ground as power is transfered. as for VDC, probably would kick in more often than not, since its noticing more lateral movement.

 

facts:

VDC, ABS and stability control uses the measuements from the indivdual wheel speed sensors to operate the systems accordingly.

Tire rotation is 804 revs per mile in the front and 680 rear

when the rear tire is spinning at the same speed as the front the on-board computer sees it as the rear tires spinning and will react accordingly (apply brakes / reduce throttle)

base model doesn't have VDC but it will still affect ABS

basically the car was not designed for the same size or same diameter tire on all four corners

 

Thanks luke, as always, you've been a great help.....

 

Luke-
Thansk for your input.
Can you recommend any tire size combinations that would work safely on my Z's 18"x8" wheels if the OEM sizes are not available in the particular tire I want?
Thanks,
Mika

 

The difference is not quite that big. Front is about 801/mile and rear is 780 for the stock 040's 040 Specs