This is probably going to sound like a stupid question to some of you, but I searched for an answer and couldnt find it.

I changed my rear tires not too long ago for some Kumho Ecsta SPT's 245/45/R18 because my stock rears were out of tread.

My front's are pretty much bald now, and was wondering if I could take my rear tires which are 245/45/R18 and put them in the front. Then buy a pair of 275/40R18 tires for the rear ones. would it be bad that my front's have less tread than the back?

 

In general, you want to most tread on the front of a car, not the rear. Most of the time (but not on a Z), we buy a new pair of front tires and move the old fronts to the rear. Since the Z has a staggered setup, it's not practical to move tires between front and rear.

Since you didn't say what size wheels you're on, I can only assume stock which would be about 8 or 8½" wide - in that case, the 275's for the rear are really too wide. No more than 255 for an 8" and 265 for a 8½" wide wheel is the safe setup.

 

Front tires are taller than rear. Not a good idea.

 

I am getting ready to buy new tires as well and the previous owner had 245/45/R18 all around. I was thinking of going back to the stock size 225 up front and 245 back, would this be good or can I go wider both up front and back? The rims are after market 18.

 

You can go wider in both front and back. 8" wheels will hold up to 255 wide. If you have TCS or VDC in your Z, you have to remember to keep them staggered at the proper OD. Since you're running a square setup already, stagger may not be much of an issue for you.

 

Don't know. You do not tell me the wheel size.

 

The wheel size is 18" and 8" wide. The car does have VDC.

 

I would not drive with a 275 mm tire on a 8.0 inch wheel.

 

How wide can I go in the back?

 

Read the replies. It has been posted.

 

You are welcome.