Fracture

iTrader: (5)

So I ordered some new tires online and, like an idiot, I didn't double check the sizes. The sizes CURRENTLY on my 2002 z28 (with 17in rims in the front and 18in in the back) are: front-275/40 17 rear: 285/35 18. The front ones I ordered are fine, 275/40ZR17, however I got 285/30ZR18 for the rears.

Will there be any big difference? I know that the number is how much sidewall there is, but 5mm shouldn't be too much, right? Or am I going to have to order 35 and return the 30's.

JUSTINSWS6

You wont notice at all. Your all good.

Fracture

iTrader: (5)

Thanks for the quick response, and awesome. I was worried since I need new tires before my road trip next weekend.

JUSTINSWS6

No not even a 40 to 30 is very noticeable. What brand did you buy?

Fracture

iTrader: (5)

I got some Sumitomos from tire rack. I'm tight on cash so I had to get the budget ones :/

JUSTINSWS6

They still last a long time and hook deceant.

VinR1

iTrader: (17)

The 2nd number is not the height in mm, its a percentage of the width... in your case, its a 14mm difference

The Alchemist

iTrader: (19)

Exactly, and double it for overall height because that's 14mm from the rim to the tread. So your rear tire is going to be about an inch shorter than it should be.

If you haven't mounted them yet, I'd call up Tire Rack and explain to them the error and see if they will work with you to correct it. If it was the other direction, I would say live with it, but your rear tire is going to be shorter than the front and give it a weird raked look, and it's going to hurt traction having the shorter sidewall as well.