Is it normal for the front tires on the 03' z06 to wear un-evenly?

I just inspected my tires and noticed that the LF is down to the threads on the 1st inch of tire. It has pleany of tread left the rest of the way to the outside of the tire. Do you think when I get new tires I need a wheel aligment?

Gus

 

It could be two things, first it was lowered (or raised as in the case of my car) w/o a 4 wheel alignment being done or if it's just the inside of the front tires that's normal due to the aggressive alignment spec's on the Z. When the cords started showing on my 03 Z with just 11K miles I took it to the dealer for a check up. He confirmed what I had learned from the first owner, that the car had been lowered and aligned, when he traded it the dealer said "no way will they take lowered" so he went home and raised it back up, of course since he was trading it he didn't have the car re-aligned. I buy the car and after having all sorts of issues with noise in the front end, they finally replaced the front leaf spring and then tell me about the lowering. So I buy two new front tires (275 vs 265) and had them pull some of the camber out. Basically I had them split the different between the Z06 spec's and the base C5 specs.

I like the way the car tracks now and it feels like it's a "steam roller" since I have more contact area when the car is traveling straight. I know I gave up a little cornering ability, but I figure the slightly wider 275 will offset some of the loss of cornering power taken away by the alignment and to be honest I don't play Mario Andretti on public roads to ever push the car to it's limits so I'll never know the difference.

If that extends my tire life by several thousand miles that's a fair trade off.

So you either have an alignment issue related to lowering, or your factory alignment may be on the high side of the Z06 specs which can be very tough on the front tires.

Good luck

Tom

 

I lowered mine in 2003 only about an inch and have put at least 15,000 miles on it since (out of a total of 26,000) and show no wear like you have. I expect to get at least another 10-15000 miles out of these original tires. I always ran 32 psi ... but was advised recently that 35 psi would help with tire wear and handling. This advise came from a two owner Z06 that got 45,000 miles from his Goodyears. I suspect who lowered the car didn't get it even, and as said above, you need a good alignment.

Good luck

 

I would also suggest checking the toe - excessive toe-in or toe-out would also cause excessive wear on the inner portion of the tire.

 

Lowered and aligned mine. Wore the inside tread of the fronts after 12k. Took it back to dealer for alignment check and it was within spec. Actual was a little on the aggressive side, but still in spec. Fact is that the factory spec range will allow for uneven wear. It can be adjusted out, but I'd rather corner harder and balance out the wear!

 

I've just run into the same surprise with my 23k Z06, only noticed the cords showing when I had it up to change oil. Having the alignment checked, and it being right in the middle of all spec's, I have to believe that part of the wear is characteristics of the tires, since my back tires have some inside wear too. My C4 has more camber but never wears unevenly with Firehawks, so thats what I am going to try on my Z06.

 

My 03 Z06 did the same thing when I bought it a couple of months ago and it wasn't lowered at the time (stock ride height). I lowered it immediately and took it to a Vette alignment guru around here and he said the previous tire wear was normal due to the factory negative camber setting. The negative camber setting allows the car to generate the @1g skidpad numbers by putting more tire on the ground in hard cornering. For my purposes, I wanted the best possible handling without giving up tread life (it's a $ thing) so he basically adjusted that out. I pretty much couldn't tell the difference (which probably means I'm a wuss driving the car) but at least I am happy with it for myself.

The guy also said that a lot of people who buy Vettes by them for looks and don't like some of the mannerisms they have when they hit ruts in the road so they take them to the dealer and they accomodate them with excessive toe in and such to make them track perfectly straight.

While this post may not be technically perfect (since I'm not a mechanic) - it is based on what I remembered and. in general. the point is that I had the same problem and evidently a lot of other people have also.

 

If you don't track or autox your Z and don't mind a little less handling in the turns. Have Camber and Toe set to 0 all around. Castor just keep in spec. That should get the best tire wear and the car won't tramline on the highway as much.

The factory setting of -0.7 camber is not that bad but will help cause inner edge wear. A touch of toe-in in the front makes some people happy with the steering response. But any toe, whether in or out, will help wear out tires. Simply put setting toe to anything non-zero means the tire gets partially dragged across the road. Worse than camber in my opinion.

 

Whoa...

Great information you guys.
Thanks.
Lots to think about while I order new tires
Gus

 

The stock specs of the Z06 are designed for handling at the cost of some tire wear. In particular, the front has a lot of negative camber, with some toe out, which kills the inside edge of the front tire if you don't balance out the wear with hard cornering which would wear the outer part of the tire. Here are the actual specs:

Front Individual Toe: +0.04 degree +/- 0.10 degree
Front Sum Toe: +0.08 degree +/- 0.20 degree
Front Individual Caster: +6.9 degree +/- 0.50 degree
Front Cross Caster: within +/- 0.25 degree
Front Individual Camber: -0.70 degree +/-0.50 degree
Front Cross Camber: within +/-0.25 degree
Rear Individual Toe: -0.01 degree +/- 0.10 degree
Rear Sum Toe: -0.02 degree +/- 0.20 degree
Rear Individual Camber: -0.68 degree +/- 0.50 degree
Rear Cross Camber: within +/- 0.50 degree

I suggest that if you want better wear and don't mind a slight loss in performance, run with less front camber and near zero toe in the front. The spec band shown above for front camber is -0.2 to -1.2 with -0.7 being nominal. Run closer to -0.2 for better wear. Toe also has a range that includes zero. So, you can run less camber and zero toe and still be "in" spec.

 

That was another thing I told him (besides best possible handling without sacrificing tire wear)- I didn't want any setting that would hurt straight line performance (which I assumed toe in or out would).

 

For best straight line performance on a stock Z06, you would want a little bit of toe-in - front and rear. This would counteract the road forces generated as the tire/wheel rotates, as that would cause bushing deflection. Don't know what is optimal for straight line performance, but I would think that 3/32" toe in for the rear and a very minimal amount up front (1/16" or so) would make it quicker than a zero toe set up.

 

Well, like I said - I don't know that much about it other than I had the same problem originally with tire wear and some of my friends have also. This is what I wound up with per my request of best possible handling without sacrificing tread life and nothing that will impair straight line performance (since I'm a drag racer at heart). I don't know how good or bad this is...

(Multiple values are left/right)

Front

Camber -0.6/-0.7
Caster 8.5/8.3
Toe 0.01/-0.01
Total Toe -0.00
Set Back 0.05
SAI 10.8/11.0
Included Angle 10.2/10.3


Rear

Camber -0.6/-0.7
Toe 0.05/0.05
Total Toe 0.10
Thrust Angle -0.00

 

Just had mine aligned today after 4 years. Found the camber and toe setting had drifted or where set out of wack from factory - I was at -.9 and -1 front camber and caster was way under spec - although I only had a modest amount of inner tire wear the tech said I should pick up gas mileage and turn in with the balanced setup I have now. I have -.9 and 0 cross caster and all the other specs are in spec now - drives better but I thought it was great before - shows me.