Shimmy in high speed corners
 

I first noticed this odd behavior at Mid-Ohio last month. At the Kink (back straight has a slight right hand kink) I started to feel the car make a slight shimmy but generally feel stable there and anywhere else on the track. It only felt really odd in the rain.

Lately I've started to notice it on right hand highway curves and it's got me worried. It's sort-of like the front wheels wobble in short bursts. Could it be the control arms?

I'm going to take a trip to the dealer and see what they say since I still have ~2,500 miles of my warranty left but I wondered if anyone else had experienced a similar problem that might help me diagnose it.

Suspension is stock aside from Hotchkis swaybars, whiteline rear endlinks, and SPL camber arms in back.

My car does this too. Especially over "somewhat" rough road. It almost feels like the wheels are loose on the car for a split second and then it goes away and comes back again. I guess you have to experience it. Do you think front endlinks would help? I thought it was just my alignment settings and then that my offset may have been too aggressive but now I am starting to think it is something else. Maybe bushings?

Yup. Small bumps do seem to make it worse. I have had plenty of miles on the car where I didn't feel the issue so I dont think it is the offset of my wheels.

I actually forgot to mention that I believed it was a problem with the front endlinks as I had broken one just before mid-Ohio. (I ran without a front bar there) After replacing the endlink the problem remained.

tramlining maybe? i would check bushing, alignment, and front struts.

I would start with the alignment first. You might not have enough toe.

I agree. Get it on an alignment rack, while it is up there check all the bushings for play. Dynamic toe is not a good thing.

LF/LR toe a little off maybe

Way bad front toe... all the bushings looked good and aside from the alignment they replaced an incorrectly sized nut that I had put on the front left ARB endlink.
toe: 1.7l -1.45r
camber: -1.6l 0.2r

I definitely still felt the problem on the way home. They think it's the tires but I'm not so sure. I'm going to throw the stock wheels/tires on and see how they feel. They have been buried in my storage shed outside for exactly a year now but there shouldn't be any serious issues with the rubber, right?

yah, one year should not affect it. keep them in a cool, dry area away from sunlight when in storage. i usually keep my stack in the garage or basement, storage. for good tires i have them in those tirerack totes.

Hopefully they're wrong and it isn't the $1500 tires. :) They still have a lot of tread aside from where I needed more camber.

wait a sec. what are the specs again? did i see 1.8 degree in toe?

Yeah... that's what the alignment printout read as the initial front toe and camber...

I think they might have been screwed up. How do you have position camber? I think they didn't take the correct reading before, what is it now?

Final is all in spec.
camber: -.8
toe: .05 total .10

front looks fine, maybe a little bit conservative with that much toe. what about your rear toe?

The initial reading of the rear was totally wacky and had to be wrong. :P
Final was:
Toe: .20 L .10 R I think he had a little trouble getting it back in spec for some reason.
Camber: -1.9 L 1.7 R. (Have the SPL camber arms in the rear. No front control arms yet)

once again, it seems normal enough ( a little conservative), but nothing funky like toe out in rear. if you think your tires are okay, i still would look more into suspension pieces. my z is pretty stable at speeds

I agree. I was fine until Mid-Ohio this year. I'm honestly not sure that the tires (AD08) can cause this sort-of sensation and it seemed to be getting worse through only street driving.

I'm throwing the stock wheels/tires on and taking a spin after traffic dies down tonight. Since the weather is so nice this weekend I may throw my coilovers back on and go find someone else to pay for ANOTHER alignment. :P

This happened on a buddy's car also and we checked his sway bars end-links and noticed that they were loose. Check out the suspension and see if anything is loose.

The mechanic friend I took it to said everything was tight... I had also checked all the bolts I could reach. I'll triple check while I change tires.

On the lower steering joint should the bottom bolt have a nut? :P I can't tell if it should or if it's just screwing into the bracket.

Wheel Bearings?
 

Talked with the master tech at the dealer when I bought the car. Wheel bearings are a known weekness of the car. Most cars have tapered roller bearings, the z has dual angular contact ball bearings. He said it was probably a gas milage decision on Nissan's part. These have been know to go out early on track driving. Tell-tail sign is if you need to pump your breaks once before they feel good after hard corning. That's the rotor flexing and pushing your pads away from the rotor. First pump gets em up close again before you start breaking.

sig11
This weekend I replaced my coilovers with KW V3's and the issue went away a little bit. I am pretty sure it is my Sway bar end links however. Are you supposed to be able to wiggle them by hand when the car is jacked up? If not.. That is my problem. I will probably be replacing them regardless.

Correct me if I'm wrong but I'm pretty sure that sway bars/end links should be unloaded when the car is on the ground and loaded when the suspension is dangling.

I am not sure. I think that is correct, which is what leads me to believe that mine are bad. I would take it to the stealership, but I am just out of warranty and I hate dealing with them!

Front end links are $27/each and you should get an alignment after replacing them. No aftermarket/adjustable option exists for the front end links unfortunately. It's an easy job if you have a torque wrench and breaker bar.

Think we finally found it. I'll know in about 10 minutes when I leave the dealer.. but it seems like the left rear camber arm was loose and working itself looser.

Any new update on the issue? I'm starting to experience something similar after my last track event. All suspension is still oem, tires AD08's although the tires were pretty much worn out. I'm hoping it's just from worn out tires I've put my stock bridgestones back on. I'll also check to make sure nothing came loose.

Sorry. I had meant to post sooner but forgot. The left rear camber arm worked itself loose at the factory adjustment bolt. Car felt great again after taking care of that.

Awesome, glad it all worked out man!

I just noticed this problem on my way to work as I was taking an on ramp to another freeway slower than usual but going 60mph on the turn. My car felt like it was wobbling. I had just gotten new tires as well as a Spl rear camber kit. My alignment specs came out okay so I was thinking it could've been the v12's? They only have like 250 miles on them. I'm goin to try replicating the problem again once I get off and see how it goes.

Interesting... My car does this slightly, but usually in parking lots and the steering wheel almost turned full lock. Its still pretty cold here so I though it was the tires skipping a tad due to no front grip. I guess I should go to the dealer.

(My car has 700 miles on it and I noticed this the first day I bought it)

This is normal, especially when cold.

May be the tires... If you can jack it up it shouldn't be hard to just double check the bolts are tight though. If they feel loose you may want to get an alignment check. The problem in my case could be demonstrated with the help of a pry bar. A little force would make it obvious that the stock adjustment bolt was loose.

Sig did you ever figure out what the issue was? Mine ended up being a really busted rear diff mount.

Sure did. Solution on p2. :) The stock camber adjustment bolt came loose and was allowing the left rear camber to change randomly.

Ha well I guess more than one cause for a similar symptom. Glad you got it figured out man.