Hi, Just getting my 71 convert project wrapped up and went for an alignment today. Pretty sure I got ripped off as they didn't do much of anything on the rears, but don't know enough about alignment specs to know if further action is needed. Here is what I gave them (have VBP upper A-arms).


and here is the spec sheet after the alignment.




Does this warrant further work to get the rear toe pushed out, or is it OK?

Thanks in advance.

 

total toe up front is going to eat some tires ,

 

Hi Eric, Total toe started at 1.16* and then the "actual" or after alignment value is .001*. that seems pretty close to zero toe, right? Or am I missing something?

 

They a nice job of getting them equal side to side. Rear toe is an involved job of adding or moving washers on either side of the trailing arms. Your typical shop wouldn't have the expertise. and I'm not sure about conversion of degrees to inches. you want some rear toe I tried Zero for drag racing. Rear toe gives the rear self correction.

As to camber required. It can only be done with temp gauges in a tract test day or the old fashion way watching the tire tread ware.

Front Castor: I run 6.8 and zero toe. It makes a vette very stable at speed

 

looks like they did not touch your rear.. you need a variety of shims.. betting very tough to get bolt loose too.. post pics of rear shims..
see post # 46 +
power steering control valve leak rebuild question - Page 3 - CorvetteForum - Chevrolet Corvette Forum Discussion


79.. after trip 2 front was done

 

Interpon, I wouldn't except an alignment that is that far off. Your side to side camber is way off making your car with predominant higher right camber. Which would give the car higher traction turning left.

Some bad shops will try and tell you that's for road crowning. What it really means is that your tires will ware differently from side to side. Lower than required camber will ware the outside of the tire and higher like .8 and .9 will ware out the inside.

Stock front A-arms can be set to 4.5 castor. It makes the car really drive so much better.

 

Thanks. My rear toe is clearly something I need to address to get it in the range of 0-.12* on both sides. Will post pictures of my shims in the next day or so as well. If someone can look at the specs, and pictures of the shims, and recommend the appropriate shims to reduce the toe, that would be amazing.

 

Positive toe on the rear makes it unstable on the freeway

 

I didn't think about green rear toe. You are right unstable

 

not sure what op manual says but mine drives great and highway…what is off on mine? I thought they look as good as the toghtest spec in manual..

 

This chart would seem to indicate the inches to degrees conversions -- 1/8" is 0.12°. Kinda odd that the inches to degrees are the same as the decimal equivalents... maybe gotta think on that... I'm unclear on what is being measured for the inches whereas the degrees are around a central pivot point...

 

your rear toe spec is 1/8” TOTAL. Meaning .06 each side

 

Looking at what you posted they didn't do anything on the rears other than record some values. You need to find a shop that knows how to do classics cars and Corvettes in particular or as in my case a young kid who took it on as a learning experience after I walked him through the process. If your rear trailing arms have never been off the car this could be a major issue as the bolts and shims will most likely be unusable and this is an area you don't want to get into on the alignment rack.

 

I'm sitting here pondering that as well.

Shops today just punch the car into the computer and make adjustments until the numbers read green. When I had my 65 on the rack there was no pro-loaded car to pick from so it was a "manual alignment" using Spec's that I provided. I don't have the sheet they gave me so I can't see if it said degrees or inches.

All I could find in my searches is (1/8) * 180 = 22.5°, so if the rear Spec is 1/8" total toe that would be 11.25° each side. I will defer to our math geeks for clarification on all this.

 

OK I am guessing the car drives very well with these settings.

So based on the specs you highlighted here is what the alignment machine should display.


Front wheels
Total toe spec = 0" which should be 0 degrees. They hit 0.01 which is easily within spec.
Camber spec = -.25 degrees they hit -.3 degrees again easily within spec.
Caster spec = 4.75 degrees they hit 4 degrees but most important equal on both side.

The front is perfect for the target specs you provided.

Rear Wheels.
Camber spec = -0.5 degrees they left it unchanged because they were already set correct.
Total toe spec = 1/8" toe in which calculates as 0.2652591860630703 total degrees.

So your rear toe is actually .18 inches so ~ 5.76/32nd or rounded up to 3/16 inches this is very close.

I would consider this alignment as perfect as you can get it. And here is why. If you drove the car around the block and re-measured this again. YOU WILL NOT GET THE SAME MEASUREMENT !.

Your C3 suspension is not solid and static. All the suspension joints move. I would consider this alignment perfect based on the spec's provided.

Usually I take 2 measurements.
1 drive the car to a flat surface on dry pavement. Take measurements.
2 then put the wheel on skid plates (Teflon sheets with grease in between the sheets) and compare measurements.

If they change a lot meaning more camber and more toe your suspension is loose and worn. Could be bushings / ball joints / tie rods etc.
But note they 2 measurements will be different. I allow for ~ .1 degree camber and ~ 1/16" toe changes. but even at .2 degree camber and 1/8 toe changes you wont be able to notice this on the street while driving.
This will show as tire wear over time. Which means you need to drive your car more than 2000 miles a year.

And if you want a easy method to convert inches to degrees or degrees to inches use this online calculator. This also shows where measurements are taken for inches

Convert Toe Inches to Degrees (robrobinette.com)

If you are interested in DIY Alignment here is what I have done for my 78 for track day setup.

My DIY Alignment method - CorvetteForum - Chevrolet Corvette Forum Discussion

 

Great info, both here and your other post.. Nice to hear I am in good shape, and yes the car does drive well. All suspension parts are new on this car, and it would be a :15 minute job to pull 1/32" shims from the outside of each trailing arm and move the inside to get rid of a bit of the toe... But to confirm, your thought is that would be unnoticeable and unnecessary?

 

lol , somehow I missed the after setting

 

Correct don't worry about it. Just monitor tire wear but you will need many miles to notice anything.

To check this companies alignment you could take the car to a dealership for measurement only. My local dealership charged me $30.00 for measurement only.
I did this to verify my DIY alignment measurements when I started doing DIY alignments.

They will not get the same readings but they should be close.

 

I agree with cagotzmann, looks like they got it spot on what you asked for. If it were me then personally I would have gone a little more aggressive on some of the alignment settings, but it depends what you're using the car for. It should drive well with the alignment shown.

 

Well personally they did not touch the rear, and it is not inside their own spec of .25 degrees (1/8"), or the book spec.
You are at 3/16" toe in the back and the spec is 1/8" so you have 50% too much.
I would have them fix it.
As someone said it is literally a 15 min job to move a small shim from outside to in.
Someone suggested a 1/32" shim.
But they will not have C3 only shims, and you may not have a 1/32" in there. So...
Buy a shim pack and take it with you.
The only difference really would be less inside edge tire wear on the rear. Do you want to cut it down by 30% or more? It will drive the same. (I had a car that destroyed rear tires do to this issue.)
The front is spot-on.