My Z06 is a 2003 model. I don't track it (at least not yet ;-)) or autocross. I have three alignment questions.
1 -- since the recommended alignment is heavy on neg camber, should I be concerned about premature tire wear?
2 -- i notice this car needs to be DRIVEN. My wife's '99 base vert is much more civilized. If I leave a loose hand on my steering wheel, the Z will drive itself, which is not a good thing. Is this primarily a result of the caster, camber, or toe settings?
3 -- does anyone have a recommendation for alignment specs for a street driven Z06?

This car has under 15,000 miles, so I fully expect a tight front end that can be aligned to pretty accurate tolerances.

Thanks in advance. 37Pat.

 

My guess is that the previous owner put an aggressive alignment on it, and that probably includes very little front toe in or maybe even a bit of toe out. Autocross and track cars use a bit of toe out to help the car turn in. You want about 1/8 of an inch of total toe in for a street car. For an autocross or track car you want about 1/8 of an inch of toe out or even bit more.

A bit of front toe out will most certainly keep you from falling asleep at the wheel, the car will tend to "tramline" or whip from side to side if you get in deep double rutted roads, and the car will follow pavement edges and things like that. What a car with toe out in deep snow will do is really scary...

My guess is that your car has very little toe in or even a bit of toe out in the front. Get it aligned and you should be fine. While the Z has a more aggressively tuned suspension, it shouldn't be unstable or be that bad when you are going down the highway.

The stock alignment settings are fine for a street driven car, just get the tech to hit the numbers and not get "close" or within spec. A good alignment tech will take a few more minutes and get it right.

Also make sure the tech really torques the alignment eccentrics. These have a bad habit of slipping and that could also be the cause of your alignment issues. If they aren't torqued really tight they will slip and you can get some funny handling.

You bought a performance car, not a Prius... If you have a problem with a bit of tire wear you bought the wrong car... The amount of tire life lost at the stock alignment settings is small. I run -2 degrees of negative camber in the front and -1.5 in the back, the small amount of negative camber in the stock setting is nothing...

 

Thanks Solofast. Apparently, the toe adjustment is the issue. I've not observed rapid tire wear from the present (presumed factory) alignment, but wondered if the factory alignment caused this type issue. I want the car to perform well, as a street driven car. And it certainly seems to do that. Thanks for the response.

37Pat

 

Get the alignment checked no doubt. As solofast said toe out can make it very touchy. Also if camber and caster is equal to each other, it can cause a slight wandering feel daily driving. This is because the road crown leans right and you are tugging left on the wheel to compensate. Then you start over correcting as you drive. Get the caster about 0.30 higher on. The right to offset this.

As solofast said make sure the tech gets the numbers on spec and not just in the tolerance area. If you are worried about inner tire wear from the aggressive negative camber, then have them set it to the base c5 specs for camber. You'll trade off a little bit of cornering for better tire wear. But that's your decision.

 

The Z's were aggressively aligned from the factory. You will get premature tire wear on the inside fronts. So much so, that the outside will look somewhat normal, but if you take the tires off or get under and look at them, you might see the steel belts.

You can get it aligned to the coupe/vert specs which will give you a better wear, but your performance will not be there anymore, but since it's just street driven it won't matter.

 

more aggressive than a coupe yes, but aggressive? not really

solo is dead on with the toe comment.

any toe out makes one of these turn in very fast which some see as twitchy or unable to track straight. great for autocross, horrible for the freeway or high speed

a slight toe in out back also improves stability...why the factory never did this one is beyond me

 

Sounds like a question for the "Ask Tadge" forum!!!

My thought is that they went with a happy medium, so it would perform well at the track and well on the street, without having to flip flop alignment settings for the weekend track warrior...

 

would perform better on the track and on the street actually

the only reduction would be tire wear since there would be a slight scrubbing

this may have been the GM reasoning

 

I have my o3z aligned to the coupe specs since I don't track and only use as road/trip/weekend club car.

 

Z's come very soft from the factory IMO. I run:

Front - 0 Toe, 7.5 Castor, -1.2-3ish Camber

Rear - -1/16th" Toe, -.9 Camber.

When I did that it transformed the car in how it drove and the feedback I get....

With such wide tires you don't want to go higher in Camber, and it mainly Toe that kills tires. Have over 20K on my fronts, over 15k on the rears and they all look great. (Nitto's, NT555 front, NT05 Rear)