I plan on getting new tires installed in the near future at Discount Tire. My question is do I let them do a wheel alignment, or do I take the car to my Chevy dealer for that job?

 

 

 

I've been in the same threads you're talking about and I agree. If you want it done right, do your homework and find the right place. Don't assume a dealer knows because as was discussed in those threads they didn't even know there was a camber setting.

 

I had both my C5Z06 and C6 aligned at a local Les Schwab but not a C7 yet

(they do just fine with 'em)

 

 

 

I hope they have a hunter revolution tire changer to change your tires !!!!

 

 

Just as important as where you go, is how you want it set up. So put some real thought into that before you have it done. A car that will see track duty will be set up much differently than a street only car.
The critical issue with the rear suspension is setting castor. The dealer should be able to do this but ask the specific question, "can you properly measure and adjust rear castor" ?
Camber setting on the front should be close to zero, if not at zero, on a street car where tire wear is the primary issue.

 

Regardless, of which car you have, if street driving is your main goal, have it aligned to the basic C7 specs. If you have a GS or Z06, the tires will last much longer. I had the base alignment specs applied on my 13 GS when I bought it new and I got 15,000 miles out of the original Goodyear's.

 

Discount tire stores in my area do not do alignments.

 

Car is a 2015 Z-51, that has not been lowered. I copied the settings, which changed from 2014 to 2015, for street use from this forum. Now I need to decide where to get it done.

 

I got my tires installed at Discount Tire and then I ran over to my Chevy dealer to get it aligned the same day. More expensive than most shops, but everything seems fine so far.

 

 

My dealer was clueless.

 

If they don't have the CH-47960-10 rear caster gauge tool, then they cannot fully, properly do the alignment of the C7.
That would be my first test. If they do not have (or refuse to get) all the necessary tools, move on.
It's really quite that simple. No CH-47960-10? They can't align it.
Very few have the tool. Even several GM dealerships don't have it. I'm fortunate that mine does.

 

Many (most?) dealerships are still clueless about the rear caster measurement and settings on a C7. It takes a couple of special tools and someone who knows what to do.

Our local dealer tech knew all about it but the boss hadn't bought the tools because nobody had ever asked. Hmmm...
But as soon as I did ask, they got the tools in a couple of days and did my alignment, with rear caster, right away. Little or no additional charge.
My rear caster was exactly at factory spec, but I've heard mention of some cars being significantly off.
Some people are adamant that a different rear caster setting improves handling, but I don't have a place to properly test and so I went with stock. Seems to work well on the road and in autocross.

(EDIT: Joe types faster than me. Also has excellent taste in C7 colors)

 

It isn't any harder to do an alignment on a C7 than it is on any other car requiring a 4 wheel alignment. However, it requires special tools to measure REAR CASTER and this is where things get screwy. The vast majority of cars on the road do not have adjustable REAR CASTER (the only ones I know for sure that have it are the Pontiac Solstice, the Saturn Skye and the C7). Since shops and mechanics don't do many alignments on cars like these they just don't know about it. When you say REAR CASTER they automatically think you are talking about front caster. If you ask them about REAR CASTER most shops will say we can do it on our machine since they are thinking front caster. You may have to repeat that statement 100 times before it sinks into a mechanics brain that you aren't talking about front caster. NONE of the alignment machines on the market can measure or even print out rear caster information. When the mechanic in an independent shop checks their machine they will not see REAR CASTER mentioned and that will reinforce their mindset that you mean front caster Vs REAR CASTER. This is why you need to have a discussion with the shop about their capability to make the measurements (if they can measure they can adjust).

To make the measurements GM recommends the following tools:
Digital Angle Gauge, CH-47960 (specified for Solstice and Skye, recommended for C7)
Digital Angle Gauge Adapter, CH-47960-10 (specified for C7)

Any sufficiently accurate digital angle gauge (0.1 degree accuracy) can be used instead of the CH-47960. The GM tool just makes things a lot easier to do since the directions are clear when it comes to zeroing the gauge depending on which side of the car you are working on.

Some people have substituted two 1/4 inch bolts for the gauge adapter and that seems to work but that means the mechanic has to hold a gauge that is long enough to bridge between the two bolts while trying to adjust the cams on the lower control arms while also looking toward the alignment machine's readout of rear camber at the same time. Imagine doing the left rear, the mechanic holds the gauge against the two bolts with the left hand while using the right hand to turn the lca cams while watching the rear digital angle gauge for the caster measurement while simultaneously watching the alignment machine's rear camber measurement to get the two adjustments set right. A little awkward but doable if you don't want to pay $200 for the adapter. When you are paying by the hour for somebody to do this it is a lot easier to have the proper tools available.

I recently had an on track incident where the right rear of my car hit a tire wall at a pretty good speed. Damage was limited to bolt on body parts and the right rear suspension. They had to replace the uca, lca, knuckle, wheel hub and the toe link. That meant the alignment had to be redone. The body shop had a neat Hunter Alignment machine but it had no provisions for doing rear caster. I talked to the manager of the body shop and the mechanic doing the work about rear caster and told them I had the tools to do the measurements. The mechanic used my tools and was able to get the settings I wanted without much trouble. It took an extra hour to balance the rear camber/rear caster adjustments to get the numbers I wanted for both.

GM says rear caster is good at each wheel if it falls into the range of negative 0.8 to positive 0.8. They don't specify a Cross Caster like they do for the front caster measurement. However, since a proper rear caster setting helps to reduce rear bump steer various track experts say rear caster should be set at positive 0.7 on both sides of the car for best handling.

You will find that a number of Chevy shops will know about the rear caster adjustment and have the tools to do the job. Others may know about it and won't have the tools because they don't want to do the adjustment as it takes extra time. For dealerships that don't have the tools they can borrow them from GM through the dealer loan program. Almost 100% of the independent shops will have no idea what you are talking about when you first talk to them.

It really isn't about the shop you go to so much as finding a shop with a mechanic that cares to do the job properly (not a green and go job) and has the tools available to do the job properly. That could be a Tire Store, Joe Blow's garage or the dealership. If I can do it with a couple hundred dollars of toos and by crawling around under the car sitting on my garage floor a trained mechanic should have no issues doing it using $30K worth of fancy equipment.

Bill

 

And they can still screw it up.