cultcar

iTrader: (1)

I've noticed over the last few weeks a twitchiness in the rear that appears when changing lanes over uneven roads or when taking a high-speed turn. I have VDC, but the indicator light isn't coming on. The tires have 3/32 to 1/4" of tread. I had tires on the rear a month ago that were bald. These tires are used ones I had stored for about a year and a half (Dunlop Sport Maxx). They were great during the first time my car was wearing them. They are stock size 245/45-18 and I considered side wall flex. I inspected the rear suspension and all bushings are solid with no cracks (71,000 miles).

The pavement isn't grooved. Even if it were, both front and rear would track with the grooves, not just the rear.

During a high-speed sweeper (90+ mph) the twitch is in the direction of the turn and then returns, and does this with a rhythm, not random at all. It's a spooky feeling. I don't feel like I have control. I try to gradually stop whatever I'm doing to make it go away because it's unnerving to persist.

I dropped 2lbs from the tire pressure and will see if that makes a difference, and I'll also try switching off the VDC in the high-speed sweeper, but I think both will not change the behavior.

HELP!!!

cubu

iTrader: (21)

maybe your rear shocks are going out? or maybe your alignment is off

350Zenophile

iTrader: (20)

Tires. Different brands front and rear?

z350boy

iTrader: (9)

You need an alignment.

TeAm PrOSpEc

iTrader: (1)

I agree... I know I needed a alignment but I waited. In the mean time I put NF210"s on her. When I was coming back from VA beach this last weekend, she did the exact same thing your talking about. It was so bad that I had to slow down to about 25MPH on the highway. That was a first for me so I know it's the alignment.

350ZTheStandard

iTrader: (4)

I think the rubber is shot & the issues are at high speed under load the car has a twitch, also never hurts to look at the age of the springs also. How many miles on your Z car?

racerbob4

iTrader: (8)

Nut and bolt both front and rear of the car. You might have a suspension bolt backing out.

350ZTheStandard

iTrader: (4)

71,000 miles age of suspension components and the rubber is not as sticky as when new or on warm roads, grip is not at a premium in the winter.

cultcar

iTrader: (1)

The source of the problem revealed itself. I blindly took this as an opportunity to replace my shocks and springs. After the installation I drove it over to the alignment shop. As they started setting up the technician found the passenger side rear wheel was wobbling when rotated to a certain position. The bearing was shot! We hadn't noticed it when we removed the wheel to install the suspension kit an hour ago! The key is to try and wiggle the wheel at different rotation points. Don't know why we didn't think of this first, except that it just didn't seem possible at 70,000 miles (2003 model).

I then talked to another Z owner this weekend who tracks her '05 35th Anniversary track model an inordinate amount, like every other weekend. When she reached 70,000 miles her passenger side rear wheel bearing also failed!!!

Get ready to have yours repaired under extended warranty or have repaired for 400 bucks, to include bearing and bearing assembly (which didn't come with a bearing!)