My car has the Z51 suspension and four Goodyear F1 EMT tires. I believe these are run flat tires. I noticed my front tires will need to be replaced. The inside tread on the right is bald and the inside of the left is getting there. The back tires are in good shape. I drive the car often (no track days) and have decided to go with all season tires. Now for the question. Will there be any issues mixing all season tires with summer tires and/or run flat tires with non-union flat tires? And yes, going to have an alignment. Thanks in advance!

 

The reason your car has wear issues in that spot is the alignment is too aggressive. Is this the alignment from the factory?

I have mixed both A/S and summer tires with no problem, and have mixed RF and non RF (both A/S) long enough to install exactly the same tires on all four, but I'm sure someone will come along shortly to say "That's Crazy!"

What I would not do is mix tire type/brand on the same axel.

I would recommend buying almost any other tire than the OEM GY Runcraps! I've had very good luck with both Michelin and Bridgestone.

When installing the tires, get an alignment that is as close to 0 on all measurements as possible. There is no reason to need an "aggressive" alignment for street driving, and it will save your tires in the long run, as will frequent alignment checks.

 

I just replaced my GY run flats on the front with Michelin Pilot Sport all seasons and have no problem. I plan on replacing the GY's on the rear with summer tires; I do this so my steering tires can handle in wet conditions if necessary. I ran a similar setup on my C5 with no issues.

 

Thanks owc6. As for the alignment, I have no idea. Just bought her a month and a half ago and have put over 1,000 miles on her. I knew the front tires were not as good as the rears, but didn't examine them closely until today.

 

your alinement is fine what your describing is normal wear, if you have it alined, I will bet the guy will tell you that it's spot on factory #'s

 

Which is bad for wear for normal (even spirited) street use. Tires should wear evenly across the tread when aligned correctly for that use.

If you only drive on the street, and your tires show uneven wear, it is due to basically three things: under inflation (both sides show more wear than the center of the tire), over inflation (both sides show wear in the center), or your alignment is off (any number of weird wear patterns).

 

A couple of things, I think its a bad idea to mix tires on a car. You want equal performance on all four corners of the car, even "just street driving", and you'll probably have the nannies turned on too. So when it starts to rain, tire performance will change and it will change differently for different tires. If you are driving down the freeway at speed and it starts to rain, you've suddenly lowered the performance level of the tires and have placed yourself at risk, along with your passenger. Do any so called "spirited" driving? Now you are asking cold tires of different manufacturers to hang on to the road for you at unequal performance levels. Not a good idea.

As for alignment, CMY is actually correct. The problem is the alignment specs are quite broad from GM. The tech puts the car on the machine, dials up the specs from the computer and adjusts the alignment until he sees green numbers. Hence the stories about crappy tires, terrible tire wear, etc.

I would search the forum for the pfadt alignment specs. They are the same as the GM specs, just a much higher tolerance level. At the top of the chart is a street alignment guidline spec. I would then have the tech adjust the toe to '0', front and rear, and you should be able to get some respectable mileage out of your tires. Good luck...

 

I would never mix run flats and non run flats on a car front to back. The handling characteristics of the tires are totally different.

 

There are many factors that can determine tire wear, not just bad alignments or tire pressure. These are just the most common that are spoke of. Driving habits and road conditions are just a couple other areas that can play havoc with tires. I would imagine that its kinda hard to read an internet post and then declare that ones alignment is out, cept for the fact that its probably the most common problem, but not always the correct one.

 

 

The C6's (i know for sure the Z06) came from the factory with some negative camber on the front. This is to help in track use and cornering. If you get it aligned and tell them "factory specs" it's going right back to this and you will have inside wear on the front tires.

For those of us that actually do go around corners on a track, you want to maintain this. If your car is just a highway cruiser however, then you may want to have the alignment shop modify this.

 

Asking for trouble.

 

Sorry, but I disagree. I don't think the normal driver could tell the difference in tires. Just my opinion. Unless you are racing the car, for just normal street driving , I don't think you will tell any difference.

 

...for the most part anyway....but no way i'm gonna go into detail in this forum....LOL..

 

Follow the advice of a couple posters above: don't mix runflat and non-runflat on your car---period. And while it is "opinion" most will agree unless it's been tested by someone who knows what they're doing for every situation, don't mix brands, models of tires, etc.

You don't really need your tires to be perfectly matched to each other (and your car's performance "window") when you're driving on an open road with no other cars around at 35 mph. But you DO need your tires when you're braking fast to avoid an accident, braking AND turning fast to avoid an accident, running over your head in the rain, driving at nite on unfamiliar roads, etc.

That's when you find out the capabilities of you, your car or your tires aren't up to the job. And then it's too late. A few hundred today for two more tires--is it worth an arm, or a 10K repair? You decide.

 

Exactly !

 

Mixing tires are no no in my book. Is it the inside edges wearing off on your fronts? If it is it is too much toe in. Is it the inside 1/4 or 1/3 thread wear? If it is it is too much negative camber for your driving, take out some camber, you probably drive mostly on straight roads. There is no one Alignment setting that is good for all, depends on how you drive, where you drive. Street Alignment does not work for me as i like aggressive driving, lot of turning and burning, i had to add more camber to even out the wear.

 

I just replaced the original tires and put Michelin Pilot SS RF back on. The alignment was set at the factory spec's but I had the tech come off of that just a little to bring more flat running and longer tire wear. What you (OP) have described is normal wear (maybe higher or lower based on tire compound and mfg) based on factory set up. My fronts were at (left to right) : -1.0 & -1.1camber, 7.9 & 7.2 caster and 0.03 & 0.10 toe. With total toe at 0.13 and steer ahead at -0.04 and Currently reset at -0.7 & -0.7camber, 7.6 & 7.1 caster and 0.04 & 0.05 toe. With total toe at 0.09 and steer ahead at 0.00 I notice no difference other then it handles better due to new tires and we'll watch wear. My originals were starting to wear inside on the fronts as well. Finding a good alignment guy who is willing to explain and adjust is worth it based on the cost of these tires. Have fun!