Well I bought some 275/35/18 tires for the rear to go with my 245/40/18 fronts and the car just feels just plain crazy....in a bad way, on the highway at higher speeds its just plain scary, the car feels all shaky with understeer or oversteer im not sure the difference. But it feels like could lose control very easily and crash. It went from the most stable high speed highway car to a unstable nightmare.

Is this from not running the staggered size the car was designed for? I was going to switch to 255/35/18 in the next couple of weeks. Should I go for 245/35/18? Rims are ruff 278's and the front is 9 inch rim...I think.

Also the rear I bought were Dunlop Direzza DZ101's. Nice looking and feeling tires in the rear. \


Thanks guys!

PS ALSO Before I was running the new tires I was running 285/35/18 and the car felt like a rock on the highway, stable as can be.

 

I doubt it has anything to do with the sizes - it's probably more related to the tires themselves. While you don't have the proper stagger, since you don't have VDC that wouldn't come into play and TCS would have been noticable but the power cut and flashing Slip light.

Does it seel unstable on all roads or just one? Some tire tread patterns on certain road surfaces can feel rather squirrelly.

 

It has to do with tire heights. When you lower the rear they way you did it changes the castor setting. Ive felt the same thing whenever i run a full square tire setup on my car.

Put those new rears on the front where that tire height belongs and get a set of proper rears.

 

Doesn't surprise me at all the car handles like ****. There is a very good reason why cars don't run larger dia. front tires.

Now you know why.

 

Well like I said im about to buy new tires for the front, im going to keep the 275/35 in the back and get 255/35 in the front. Think that will solve my problem?

 

Yes it will , to bad it looks kinda stupid. They are just to small to fill the wheel wells, and look like they belong on a civic.

 

The car is slammed on Eibach sportlines, wheel gap is no longer an issue. With the 275/35 in the rear I can barley get a finger in the rear.

 

I'm surprised your TCS/VDC didn't go off with those setups. Your front overall diameter is bigger than rear, which is a big no-no. You're better off with at least 275/40/18.

 

He has an enthusiast so no VDC. TCS would pull power and be very noticable to him.

 

a. The front tires are 3.50 mm taller than the rear.
b. Dunlop Direzza DZ101 finished last of 4 here: http://www.tirerack.com/tires/tests/...ay.jsp?ttid=78
c. You lowered the car. I haven't the faintest idea if the alignment is suitable.

 

check your tire pressure. Your change in the size shouldn't affect the handling THAt much.

 

Nope, he will have to change the rear tires to bigger diameter overall than fronts. It's potentially dangerous to drive around with his current setup.

 

+1. I bought a wheel/tire package and they had 3 at 48 psi and 1 at 35 psi. The car was very unstable at speed and very twitchy. Simply running a slightly smaller diameter tire in the rear won't make that much difference and it's not dangerous.

 

I think your not qualified to make buying decisions when it comes to wheels and tires. What a mess. 245/40/18's don't belong on a Z!

Get rid of the fronts and get 255/35/18's or 265/35/18's.

JET

 

TCS does go crazy once in a while, 255/35 is whats going in the front next week.

 

Gee, you kinda' forgot to include that minor detail in your initial post.

 

Why are the 245's not an acceptable size? I have that size on my fronts and 275/40/18's on the rears on Nismo LMGT4's. I am just now shopping for new fronts.

 

run my set-up 265/35 front 275/35 rear. that'll shutup any issues diameter wise. haha

 

Actually, he meant that the /40/ part was not acceptable. When using the 245/275 combination, both profiles have to be the same (35 or 40, not a mix of them).

 

They are incredible, +1