I got your ZO6

My Z has about 12k miles on it and the original tires were doing very well as most miles are highway. Well today I noticed that the front driver side tire is showing the belt on the inner portion of the tire.

Is this an alignment issue because the rest of the tire appears to have plenty of tread left. Can I change the alignment to protect against this type of tire war in the future? If so does anyone have a recommendation for an alignment setting, I do not track the car so I don't need an aggressive alignment.

Sorry no pics

KenHorse

Modern 'vettes run a negative camber setting and this will wear the inner edge of the tread faster than the rest of the tire. If you don't track the car, you can have it aligned more towards the neutral end of the range and this will help. But it won't completely eliminate it

The HACK

Can't really tell you without pictures, IMO. Usually camber based wear should have a gradual change in wear from the inside to the outside, but if you're saying that the inside most of the tire is showing cords while the middle and out still have plenty of tread, it could also be that the toe is off.

A picture is worth...well, you know.

JerryU

Hmm, if a belt is showing get a new (or two) tires and then get the car aligned! Could be excess negative Camber. The Z06 has the same alignment specs as my Grand Sport, which like all Vettes you can "drive a truck through" (+/- 0.6 degrees Camber.)

I'll give you an example of my GS, that I had aligned to MY SPECS at ~400 miles on GM's dime. When checked, the rear's from the factory had a negative 1.6 degree Camber. OK for tracking BUT not for best tire wear. The GM spec ranges from -0.5 to -1.7 for the rears.

If you just ask for "an alignment check" mine (except for one minor item) was within "spec." There was only one Toe that was out slightly. The Dealer Tech could have fixed that one toe in 5 minutes and said "all's fine!" Instead it took ~45 minutes to match what I gave on a spread sheet for all specs (all within the allowed GM range.) For the rear's (which I remember) I asked for -0.8 degrees. That is what I got and in two years they are warn even (as is the front.) I picked the mid point on Toe, which he achieved (close to 0.) But when a Toe is changed Camber changes and visa versa so it's iterative.

Lots of Threads showing the GM range. You can ask for the mid point (in my case that would be -1.1 for the rear Camber) or like I did make it slightly less negative for better wear. Your choice. I picked the -0.8 as a compromise for what I wanted, as I also don't Track but do some "spirited driving.".

PatternDayTrader

Run it as close to zero camber as possible if tire wear is the primary concern.

JerryU

These are the specs with a pic of Negative Camber. Pic some values within spec and ask. Could just ask for centerline but closer to min Camber (most positive within spec) and zero Toe are best for tire wear sacrificing some max cornering.

Front Caster, which effects how well the wheel comes back after a turn, etc is OK within the spec range. I would NOT let the average shop mess with rear Caster. It's a different set of adjustments and without special tools they could mess it up. If you were tracking then find a Vette expert and pay for their ability and suggestions.

PatternDayTrader

+ or - 6 tenths of a degree.
Its no wonder lots of these cars scalp the tires.

JerryU

^^^
Yep, that's the problem if you just say, "Check my alignment!" The Hunter alignment machine, once the Tech puts in the proper code for your car, will show Red when a spec is out- otherwise Green.. As I said, I only had one Toe slightly out- all others were green. Can't blame him for saying the -1.6 degrees Camber on rear tires as "fine."

I made a spreadsheet with columns than showed each item with Min Max and what I wanted. Used centerline Toe but Cambers went on the more positive side of Centerline.

Bill Dearborn

The maximum front camber when the spec is applied is still -1.2 on the left and -1.5 on the right. Most come from the factory with settings right around -1.0 to -1.2. Toe out can drastically increase inside tire wear when you have negative camber. Think of it this way you have more weight on the inside edge and then to make matters worse you turn that inside edge so it is facing slightly forward which causes a scrubbing action across that side of the tire. Front toe is spec'd at +.10 degrees which is some toe in, but the tolerance is +/- .20 degrees which may mean the car has some toe out. Before changing things make sure you know what each setting is set at. I have -2.3 degrees front camber on my car and some toe in and my street tires are wearing evenly as best as I can tell. The inside edge of the tread is still showing several 1/32s of depth and the tires seem to be wearing fairly evenly.

Bill

PatternDayTrader

According the Jerrys document, the tolerance is plus or minus .6 degrees, therefore the max camber is 0.0 on the left front and -0.3 on the right front, for the Z06 and GS cars. -0.5 For both sides on the rear. This is exactly where I would set it up if the expectation was to drive the car in the right lane more than the left lane, and I wanted the best possible tire wear, and I wanted to keep it within specs.

I got your ZO6

I appreciate the replies, actually one of the more informative threads I've read without people bickering.

I'll try and snap pics in the morning.

rb185afm

I have done 6 alignments trying to get a good track/street set up. I’ve run -2.5 camber in the front with minimal inside tire wear. What I’ve found is toe kills the inside. With my toe set up for the track I was cording the inside of my front tires in under 2k miles. Keeping my -2.5 camber and going to neutral toe and I’m at 5k miles and counting with no visible inside wear. So I would look at your toe settings for inside wear.

BKorsaire

On my Corvettes, I drive and then after 30 to 5000 km, I ask for an alignment with my exact measurements, I am very firm with the guy about it. I took the GM specs, I just modified the camber front from 0.6 to 0.8. Each time, the factory measurements were really very close to the "green border", I wonder how they do their measurement at BG, probably at a fast pace, it always surprised me.

V Vette

JerryU, as always, has the best visual solutions and suggestions!!!

JerryU

I think it’s more than BG not doing a good job of setting. The springs and those huge front sway bar bushings have to wear in. Same with ‘A’ arm bushings. That is why it’s useless to have dealer “check alignment” when the car is delivered. I waited 400 miles with my Grand Sport and went over a number of RR crossings in that time.

SIDE BAR
Years ago was at the AO Smith plant in Wisconsin where they were making Cadillac frames (that is what cars had In-The-Day!). Recall touring the fabrication line where they welded the various steel members. At the end was a crude way to check the frame. Four “fingers” moved up and touched the frame in the four corners. They were equipped with simple contact switches. If one end was high or low, outside of spec, four massive hydraulic clamps grabbed the fame ends and twisted it in the direction to correct the error. It was checked again and if all passed they were put on a flatbed RR car and shipped to the assembly plant.

I told the welding engineer that I thought it was clever. He said yep, meets the spec when received at the plant. But as soon as the Caddy goes over some RR tracks at any speed those yielded welds will relieve the stress we put in and it will be out!

The C7 frame is more ridgid than ladder frames of old. But there are stresses from weld shrinkage. When stressed in use, they will reduce by slight yielding. Another reason in addition to bushings to go over some RR tracks before getting a new car aligned!

I got your ZO6

So based on the chart JerryU posted and the information Bill posted about the Toe adjustment, once I have my numbers and can adjust from there, what specs would you recommend?

Toe: 0.1 degrees
Camber: Left 0.3 and Right 0.6 degrees

Or should I still try to take my Camber closer to zero? Like Left 0 and Right 0.3 degrees?

JerryU

Those look like they would be good for wear- no need to go to zero.

PatternDayTrader

I stated my thoughts in post 10, noting the conditions as well.
Speaking for myself only, I would move the right front out of spec to zero so there was a zero split between the left and right sides, but I don't mind if my car drifts slightly right in the right lane and slightly left in the left lane.
One thing is for sure, I don't see any reason to go to .3 and .6, which are positive numbers, and I don't think its what you intended, but it is what you typed.

I got your ZO6

Pattern yes I forgot to put the - in there. I missed your first post, so you would recommend left to 0 and right to -0.3 degrees? The two sides must have a -0.3 difference if I'm reading the chart correctly for cross chamber.

PatternDayTrader

Yes that is what I would do.
The -.3 is the cross spec, or the difference between the two sides, but it's purpose is help offset the crown in the typical road with the assumption that you would drive mostly in the right lane. So let's say hypothetically you knew for sure that you were going to drive almost exclusively on the highway in the left lane, then you might want each side to be equal and cross spec to be zero, or even reverse the two. For the record, I wouldnt reverse the two but I set my cars up with camber the same on each side, because I drive primarily on highways which have less crown and mostly in the left lane. Plus I dont mind if my car drifts slightly in the direction of the road crown. I wouldnt like it if a car drifted in the direction of oncoming traffic. This is personal preference.