Hi all,

Around where I live, the middle lane of Interstate 95 is where the big rigs usually drive. The weight of them has left some pretty deep tire grooves, and they throw my 03 Z around pretty badly. Scared the crap outta me the other day when I unintentionally skipped over half a lane under light acceleration. Happened in an instant. I've tried 32 lbs in the tires, 30 lbs, still the same. On the flat and at steady speed, the car has no issues, but it seems to want to wander a bit under hard acceleration. Anyone else ever experienced this? If so, what was the cause/fix?

 

Check your toe....

If you have any toe out at all in the front, or to little toe in in the back you can get a lot of "tramlining" in deep ruts like you are experiencing...

Front toe out is great for autocrossing and track events, (it helps the car turn in) and it will also totally elimnate the need for any caffinated drinks to keep you awake on long night drives...

 

That's a "normal" thing in the Z's....Just get used to it & expect it.
Ron

 

Lotta folks think there are ways to work around that issue.

But about the only way is find another road without the rutting.

Wide, sticky tires hug the road...and in so doing pick up directional queues from the crowned and rutted surface on old and heavily travelled road. No real way arround it. Don't turn off AH.

Ranger

 

It's normal... but smaller tires and a non-agressive allignment can minimize it. On my car I have 275's and 295's w/ an a gressive allignemnt so it does it bad, but I expect it and am used to it.

 

lol

Thanks for all your replys...gotta ask one more question, tho...how the hell do ya road race a skittish lil critter like this?? My hats off to all you brave souls that do it...

 

Don't know about you all but that's about the last thing I would call my Z06!

 

Well, mostly it takes very large (as David Hobbs the F1 commentator calls them) ahem,,, appendages...

Ok so now you think that all road racers have huge manly parts, that probably is true, but actually you don't notice it much for a couple of reasons....

First, road race tracks don't have much in the way of ruts at all... you just have to be very careful if you think you are gonna drop a wheel off the track... And if you think thats about to happen you are gripping the wheel really tight at that point in time...

Second, in racing you are holding the wheel with both hands, not a gorilla grip, but it isn't the loose grip that you have on the street, and you are paying a lot of attention, so if it starts to dart at all you are on top of it and you feel a pull, but you don't get any real darting going on....

Autocrossers tend to have the more agressive toe out in the front to get good turn in, so at the lower speeds they can live with more agressive alignment, since it isn't going to be a problem at 30 mph...

The really brave guys are the ones who have an agressive autocross front toe out and drive their cars to the track. I had a friend who was pulled over because the cop thought he was drunk... He told the cop "you try to drive this thing in a straight line!!!" The cop when to the end of the block turned around and came back, got out and said .... ok, I believe you,,,get out of here .

 

Had the problem on my 97 but not so much on my 03Z. My solution was just a little toe in. That greatly reduced the wandering. Used to be that I adjusted the alignment on the 97 everytime I went to the track or went to a multi-autocross weekend. After 2 years of doing that I got tired of it and decided to leave it with just a little toe in since most of my miles are on bad roads. It turned out that it didn't reduce my turn in enough to bother me while autocrossing or running on the track.

 

I have one road that this effect is felt for about 2 miles, it is a blacktop two lane that is used by heavy trucks. The first time I felt it I thought I had a seperated tire and actually pulled for a look, luckily that majority of the raods that I might for some reason exceed the posted limit are concrete and thanks to the lack of frost crack and hole free (another benny to living in FL)
If your car tracks good on the flats and is wearing tires well I wouldnt change a thing, big tires follow the road.

 

Another cause of the wandering under acceleration could be worn control arm bushings. This is common in Z06s that are driven aggressively or tracked, even with relatively low miles.

 

Again, thanks for the replies. Methinks I'll get the bushings checked, and just stay off 95...it's like a warzone on there, anyways.

 

I have found this problem to be very perplexing.
The SC tires are scary & all over the road at high speed, they love to follow all the grooves in the road...it was a battle to keep it in my lane.

Ended up having the car aligned several times (it has to be exact, not
within a spec range, but right on the money).

I also installed Nitto R2 extremes 305 35 18 in the rear....great tires.
The steering was much improved by using Nitto 255 45 17s in the front instead of the 265 40 supercars. They also filled the well a little bit
more.

Steering was no longer darty ..took a lot more input to change direction, but it was much more stable and you get used to putting in more effort for canyon driving...also better high speed safety.

Also the Nittos are much much better in the rain and can handle my 523 rwhp.

 

Good stuff here, Ive already decided that i would switch to Nittos next go around.

 

What a cool forum!

Thanks all for sharing your thoughts and experiences.

I do want to keep my Z stock, but the thought of it changing lanes while my wife is driving just leaves me cold. Steveszvette, I've been reading good things about the Nittos, and your post helps make the decision to give them a try that much easier.

Any other comments on the Nittos, good or bad?

 

There really isn't anything in these cars that should make them uncomfortably darty unless something isn't set right, so the alignment shop is your first stop.... Really the only difference between a Z and a regular vette in that department is the fact that we have an aggressive tire and some more static negative camber.

If the toe isn't out of whack when you put it on the alignment rack then you might take a little bit of the static negative camber out of the car. Going down to something like .25 degrees of static negative camber per side will help that, or you could go all the way to the base suspension camber settings in the front as a last resort. Yea, you might loose a bit of grip at the track, but if you aren't going to track the car you aren't likely to notice the difference. Then you can give the keys to your wife and not worry about it....

 

ha ha....give the keys to your wife and she won't give them back! Chicks rule!!!

 

And when you drop a wheel, or two, at speed. The first time those appendages shrink really quick.

I daily drive mine with a track alignment. I swapped to the FS Wide Ovals for street use since they're pretty cheap. The car wanders less with them. Smaller, skinnier, lower grip tires tend to reduce that feel. The GY SC do it because they grip that well for street tires. I use my SCs on the track and love them. I don't feel any wandering at all.

I would not run Nitto R2 on the street. At least not the Road Race ones. If you guys are talking about the Extreme street tires sure. The R2 track tires feel nice on the street when they are new. They'll track like mad after they get some wear and are wild in the rain. They're track/autox tires.

If you zero out your alignment to no toe or camber and run smaller tires then you'll help the tramline effect. But you'll also dummy down the cars ability to handle when you want to play. 0 toe front and 1/16 to 1/8 total toe-in rear works well.

 

the freeways (i-10 especially) here are horrible. All the trucks from cali have ruined it. I just bought some hres from pio (with 265 fronts) and it totally eliminated the wandering. My truck is a different story on the otherhand. It has 49"x 21" tires and its a handful.

 

I like the Extremes so much, I bought my second set (rears) and am very pleased with the improved traction across all temperature ranges over the SC.
I wore my first set to the nub and they performed well without any change in tracking. The front tires might cause mild understeer due
to being undersized (maybe use 275 40 for serious track use), but they are not tracking at all with the miles that are on them.
You can talk to Ducati and Yamaha owners about how these tires work in the canyon.