C2 Alignment Confusion

[Roger P.]

Hi guys,
I replaced the rear suspension on my '65 about 3 years ago and then had the car aligned. I gave the "frame & alignment" shop a bag of slotted shims for the trailing arms and the specs from the Assembly Manual. At the time, I didn't know that the specs for today's radial tires are different than what GM called for back in the day with bias-ply tires. The main difference that I recall was the front was set with nearly 0.5* of positive camber and about 0.5* of total toe (about 0.25* per side). The rear specs were all good. They explained that it required a lot of work and gave me a "discounted" rate of $ 225.00 due to their relationship with my brother's automotive repair shop. Recently, the only change that I made to my car was to lower the rear about 1/2" with longer leaf spring bolts and I rotated & balanced the tires. I have knock-offs, so I had to beat the %#?@ out of my spinners with a lead hammer to R&R the wheels. I decided to have the alignment checked and "tweaked" at a local tire store with a Hunter DSP600 machine. The shop manager assured me that his alignment guy was "old school" and knew old Corvettes. With a coupon, the alignment only cost me $ 50.00. However, when he put my car on the rack, he showed me how almost everything was out of spec. He told me that setting the front camber and rear toe would take hours to do because of the shims, and for the basic alignment, he could only set the front caster and rear camber. The rear camber on each wheel was just over -2.0* , and he set them to -1.5* because the rear toe got worse (was increasing from about 0.5* ) as he corrected the camber. How could my alignment specs get so messed up when all I did was lower the rear a little? At this point, assuming the car drives & handles fine, I will do a "real" alignment in a couple years when I replace my tires. My question is: Can I drive my car without any safety or handling issues with too much negative rear camber (-1.5*), too much rear toe-in (0.65* left & 0.20* right), and some positive front camber (0.25*)? I am especially confused about the disparity in rear toe numbers between the left & right wheels. I don't believe that any shims had fallen out on the left side, but I will look closer in the morning... Would I notice a gap between shims? By the way, my tires have been wearing evenly (a little more wear in the rear) with over 4,000 miles on them in nearly 4 years.

Thank you,
Roger

[Michael F.]

Re: C2 Alignment Confusion

can't help you, but feel your pain. I had a major issue few years back with a local chevy dealer who had "old school" knowledge/vette experienced alignment guy.........NOT. ended up getting money back and took it to another dealer who fixed the previous dealer blotched alignment...............good luck.

[John H.]

Re: C2 Alignment Confusion

I decided to have the alignment checked and "tweaked" at a local tire store with a Hunter DSP600 machine. The shop manager assured me that his alignment guy was "old school" and knew old Corvettes. With a coupon, the alignment only cost me $ 50.00. However, when he put my car on the rack, he showed me how almost everything was out of spec. He told me that setting the front camber and rear toe would take hours to do because of the shims, and for the basic alignment, he could only set the front caster and rear camber. The rear camber on each wheel was just over -2.0* , and he set them to -1.5* because the rear toe got worse (was increasing from about 0.5* ) as he corrected the camber. How could my alignment specs get so messed up when all I did was lower the rear a little? At this point, assuming the car drives & handles fine, I will do a "real" alignment in a couple years when I replace my tires. My question is: Can I drive my car without any safety or handling issues with too much negative rear camber (-1.5*), too much rear toe-in (0.65* left & 0.20* right), and some positive front camber (0.25*)? I am especially confused about the disparity in rear toe numbers between the left & right wheels. I don't believe that any shims had fallen out on the left side, but I will look closer in the morning... Would I notice a gap between shims? By the way, my tires have been wearing evenly (a little more wear in the rear) with over 4,000 miles on them in nearly 4 years.

Thank you,
Roger

Roger -

Smoke and mirrors are apparent here. The caster, camber and toe on the front wheels are the same as ordinary Chevys of the era, and front caster and camber are both set with shims and are inter-related (you can't set one without affecting the other); nothing here is exotic or unique to Corvettes.

Rear camber takes minutes per side to set - only rear toe takes time, depending on the condition of the trailing arm front pivot bolt and shims. For normal street operation with radial tires, the following works well:

Front camber = 0*
Front caster = 1.5* to 2.5* positive
Front toe-in = zero to 1/16" TOTAL toe-in

Rear camber = 0* to -1/2*
Rear toe-in = 1/16" TOTAL toe-in, split evenly across the thrust centerline (1/32" per side)

[Roger P.]

Re: C2 Alignment Confusion

Hi Michael and John,
Thank you for your replies. The alignment specs that John provided are the exact specs that I gave to the "master mechanic" as he so proudly called himself. He was very nice and wanted to align the wheels correctly, but he obviously is only used to working on late model cars. That would have been fine if he told me that in the first place and the manager didn't tell me he was "old school". I'm not going to lose any sleep over the $ 50.00, but I would like to make sure that I get it done right by someone who knows what they're doing. I checked the shims at the trailing arms and they are all in place and tight. The shims and the bolts are only a few years old since the TA's were rebuilt when I replaced the rear suspension. As you said, he adjusted the rear camber very easily, but again, as he increased camber in the positive direction, the toe-in increased as well. What was really strange is that the left toe-in was so far off (assuming his numbers are correct in the first place). It looked like he adjusted the front caster by turning the tie rods. Perhaps that was the toe adjustment?? With that said, how can I find an alignment shop that has experience working on old Vettes, or at least old Chevy's? Would my local Chevy dealership be able to do it correctly? How can I trust them based on my last two experiences? Once I find a competent shop, roughly how much should a 4-wheel alignment cost me?

Thanks again,
Roger

[Stuart F.]

Re: C2 Alignment Confusion

When I first went to radials back in 2002, the Goodyear shop where I bought the tires had a computer system and the tech guy was a Corvette specialist who worked regularly with a Chevy dealer. I seem to recall he used the specs from a later year C2/C3 chassis that came with radials. I discussed this with Duke Williams a couple years back so it should be in the archives as I sent him a computer printout. Mine has been fine ever since, in fact I'm due for new tires based on age soon and will go through the exercise once again.

Stu

[Jerry G.]

Re: C2 Alignment Confusion

Do it yourself. It's not hard and you will learn about how this car works. If you really want to have fun. "string" the car to insure front and rear are headed in same direction. If you have a little patience and time this is a DIY. We can talk you through any questions. Jerry

[Duke W.]

Re: C2 Alignment Confusion

What John said other than suggest a nominal rear camber setting of -0.5 degree. With modern equipment nominal settings should be easy to achieve, and they should be the same within 0.1 degree side to side.

Radial tires should have less toe-in than bias ply, which is why the toe-in settings are small compared to the OE specs, which were for bias ply tires.

I don't see that your current settings are hazardous, but the unequal rear toe might cause some torque pull. In any event, get it set properly soon and the car should drive better.

As John said the front caster and camber are set with shims in the upper control arm mount like any other Chevy from '55 through the next 30 years or so.

The tie rod adjustment establishes front toe, and it is done after camber and caster are set.

For manual steering, keep front caster at about 1.5, no more than 2 degrees. Go to 2.5, if possible, with power steering.

Rear camber should be set first, then rear toe is the final job.

Duke

[John H.]

Re: C2 Alignment Confusion

Jerry is right.It may seem intimidating to start, but if you have some mechanical knowledge you can do it. Last time I did a complete front suspension rebuild (C-2 ) I took it to a shop to check alignment on a machine and they were spot on. I also replaced Mazda 3 upper camber control arms with adjustable pieces and those went smoothly and had no problems. Just take your time .

[Paul Y.]

Re: C2 Alignment Confusion

Do it yourself. It's not hard and you will learn about how this car works. If you really want to have fun. "string" the car to insure front and rear are headed in same direction. If you have a little patience and time this is a DIY. We can talk you through any questions. Jerry

I agree with Jerry. String the car and have some fun. You can use two vinyl tiles with a little sand in between for ease in turning the front wheels. Camber guages are not too expensive. Not much more than an alignment or so. Or you can use an inexpensive level. Lot's of information and how to on the internet. You will be pleased at how your car feels. Go for it. Paul

[Roger P.]

Re: C2 Alignment Confusion

Thank you all for your replies and suggestions. I'm not intimidated to do a "DIY" alignment, but I would be more willing to tackle it if I worked along side someone with first-hand experience. For some reason, there doesn't seem to be many hands-on C2 Vette guys here in South Florida. A friend who used to have a few C3's just told me about an alignment guy that he has been using since the '80's; the only guy he would trust to align his Vettes. He has been following him to different tire shops over the past 25 years. I'm going to call him this week and see if he will let me observe his work during the alignment. I realize he isn't going to "string" the car, but at least I will see where and how he makes each adjustment. That will give me some valuable knowledge in case I want to go "old school"' and string the car next time.

Roger