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There is huge range of adjustment for alignment measurements on these cars.
Best option would be to take to a shop that does alignments on performance cars and request "Best Tire Wear" alignment settings.
I always consult with my Corvette customers about how they would like their alignment done before making adjustments.
That tire wear looks like normal negative camber on top of some negative toe scrub.
Absolute maximum tire mileage will come from zero camber and close to zero toe. I do zero camber on our street cars and more camber on sporty cars. Zero camber will give less than maximum cornering power but I feel that, especially a normally driven street car has plenty of cornering power for it's intended use. I include your Corvette in there because of how you drive it....normally. We have a Honda Pilot which I haven't done anything too yet as it is only 6 months old. But it will get zero when I do it. My wife has a 15 Mustang GT and it is close to zero camber. My 19 Stingray is my autocross car so it has -3 front and -2 rear camber.
Your car has negative camber. When camber is adjusted it will change rear caster. Alignment Machines Can not measure or display rear caster. So find a shop that has the rear caster tool.
There is not enough adjustment in the stock rear toe rods to get your camber down to zero and still have zero toe. I replaced the rods on my 2019 GS with Granatelli adjustable rods and got the camber down from -1.0 to - .05 with zero toe. I am getting much better wear out of the second set of PSS's and still don't notice any handling difference in street driving or spirited twisty driving. It's a convertible, so no racing.
There is not enough adjustment in the stock rear toe rods to get your camber down to zero and still have zero toe. I replaced the rods on my 2019 GS with Granatelli adjustable rods and got the camber down from -1.0 to - .05 with zero toe. I am getting much better wear out of the second set of PSS's and still don't notice any handling difference in street driving or spirited twisty driving. It's a convertible, so no racing.
Did you have excessive toe in? If the rear caster wasn't measured and then set to 0.0 that might happen since you moved the camber to an extreme position. When I was setting the DSC track alignment that called for rear camber of -1.7 degrees and rear caster of plus 0.7 degrees I found the rear toe links didn't have sufficient adjustment to reach 0 toe as well. The least I could get was about -.5 mm of toe out. When the rear caster was changed to the GM 0.0 recommendation the toe links had a sufficient adjustment to reach 0 toe and a little toe in.
I have adjustable toe links so no experience there but I also have the AMT adjuster kit. C7 Corvette Adjustable Camber Kit | AMT Motorsport - AMT Motorsport
I bring this up because I have found I really like those shims for the upper control arm. The kit gives specific #s for how much each different thickness shim will change camber. I haven't needed to source shims as the kit has quite a few of them but I suspect they are standard alignment shims. You can either ad them to the stock washers or replace the washers with them. The advantage I find is that I can easily change camber w/o affecting caster. Just put all the exact same shims at all four bolts. And, if you want to adjust caster, you can vary the shims at the control arm front mount compared to the rear mount. W/ the stock eccentrics you can adjust the lower arm but it is always a guess how much to move the eccentric to get your desired change.
Does anyone have a PDF or something that shows the GM "street" alignment specs?
Getting new tires next Monday and want to bring the specs with me.
100% street car, use it to commute till I get something else.
I run the following for requested 'Street Alignment' specs:
-0.6 front camber
7.5 front caster (both sides the same, NO caster split)
0.20 front total toe
-0.4 rear camber
0.0 rear caster (This is IMPORTANT)
0.10 rear total toe
The car still feels lively and sporty and doesn't develop the squirrelly tendencies that come with standing the tires up straighter.
Also, tread wear is VERY GOOD with these specs.
I run the following for requested 'Street Alignment' specs:
-0.6 front camber
7.5 front caster (both sides the same, NO caster split)
0.20 front total toe
-0.4 rear camber
0.0 rear caster (This is IMPORTANT)
0.10 rear total toe
The car still feels lively and sporty and doesn't develop the squirrelly tendencies that come with standing the tires up straighter.
Also, tread wear is VERY GOOD with these specs.
Thanks for the specs. I will call the location up now and see if they have the ability to set rear caster.
Did you have yours done at a place with the special tool? Or just the make shift way with an angle finder?
Thanks for the specs. I will call the location up now and see if they have the ability to set rear caster.
Did you have yours done at a place with the special tool? Or just the make shift way with an angle finder?
I am a service technician at a GM dealer, specialize in (meaning sucker for punishment) Corvette. C5, C6, C7, and C8. My son gets most of the C8's and leaves the 'old stuff' to me LOL
I bought my own digital angle gauge and index pins for C7 and C8 rear caster measurement. I do a LOT of Corvette alignments.
I have used several makeshift methods for rear caster measurement, but having the index pins and digital angle gauge makes it extremely precise and much easier.
I am a service technician at a GM dealer, specialize in (meaning sucker for punishment) Corvette. C5, C6, C7, and C8. My son gets most of the C8's and leaves the 'old stuff' to me LOL
I bought my own digital angle gauge and index pins for C7 and C8 rear caster measurement. I do a LOT of Corvette alignments.
I have used several makeshift methods for rear caster measurement, but having the index pins and digital angle gauge makes it extremely precise and much easier.
Is rear caster the spec that most shops don't have the ability to change? My alignment printout doesn't even have it on there.
Is rear caster the spec that most shops don't have the ability to change? My alignment printout doesn't even have it on there.
That is correct. Most shops will look at you cross eyed if you mention rear caster. A knowlegable dealer with the right tool can do it. I have a indy shop that can do it.
Is rear caster the spec that most shops don't have the ability to change? My alignment printout doesn't even have it on there.
As MaxPowers mentioned, yes. Alignment machines to not posses the ability to measure caster without sweeping the wheels.
I measure and adjust with my angle gauge, then hand write before and after on the alignment printout.
If customers are curious as to what rear caster is and why it matters, I invite them to their car up on the alignment rack and show/explain everything.
IMO, the ability to adjust rear caster is AMAZING. I can dial out any accel/decel rear steer and make the car an absolute LAZER.
It doesn't seem like much on paper, but once you FEEL it, there isn't any going back. Ever.
That is correct. Most shops will look at you cross eyed if you mention rear caster. A knowlegable dealer with the right tool can do it. I have a indy shop that can do it.
Most shops don't even know what caster actually is and/or does. It's just a number on the screen.
There is not enough adjustment in the stock rear toe rods to get your camber down to zero and still have zero toe. I replaced the rods on my 2019 GS with Granatelli adjustable rods and got the camber down from -1.0 to - .05 with zero toe. I am getting much better wear out of the second set of PSS's and still don't notice any handling difference in street driving or spirited twisty driving. It's a convertible, so no racing.
My C7 is an ex-track car and also has the Granatelli adjustable rods and is carefully aligned. I had the shop reduce the front camber by around 0.5 degrees relative to what it was for the track -- I am able to wear out the rears fully (nice and even wear down to "slicks"). I'm still on a new set of fronts, post-camber-reduction. This is on Pilot Sport Cup 2's ... all on the street.
My C7 is an ex-track car and also has the Granatelli adjustable rods and is carefully aligned. I had the shop reduce the front camber by around 0.5 degrees relative to what it was for the track -- I am able to wear out the rears fully (nice and even wear down to "slicks"). I'm still on a new set of fronts, post-camber-reduction. This is on Pilot Sport Cup 2's ... all on the street.
One thing you should do if you still have the Granatelli toe links installed is to put the car in the air, hold the rear wheels at the 9 and 3 positions and see if you can move the wheels back and forth. The Granatelli rod ends, like all other rod ends, will excessively wear if exposed to dirt and moisture. Many of us have already replaced the rod ends at least once and also installed rubber boots over both rod ends on each toe link. I had a 1/6 inch total play on each of my toe links which were giving me a bunch of toe changes while driving and made the car feel unstable.
If the previous owner provided the stock toe links when you purchased the car it might be a good idea to reinstall those for street driving.
One thing you should do if you still have the Granatelli toe links installed is to put the car in the air, hold the rear wheels at the 9 and 3 positions and see if you can move the wheels back and forth. The Granatelli rod ends, like all other rod ends, will excessively wear if exposed to dirt and moisture. Many of us have already replaced the rod ends at least once and also installed rubber boots over both rod ends on each toe link. I had a 1/6 inch total play on each of my toe links which were giving me a bunch of toe changes while driving and made the car feel unstable.
If the previous owner provided the stock toe links when you purchased the car it might be a good idea to reinstall those for street driving.
Bill
Hi Bill -- I will check, and thank you for pointing this out. Where do you get the rubber boots?
