C2 Wheel Alignment

[Ed S.]

I do not have a question, or a problem that seeks a resolution. Rather, I want to pass along a comment regarding information I learned on this forum and advice I received from members regarding the wheel alignment specs for a '64 Corvette with new radial tires and without power steering. My experience is offered to anyone that has a C2 with this configuration, and to thank those that provided great advice.

I had the suspension completely rebuilt about 500 miles ago, put on a set of American Classic radials and had it aligned to factory specs (as per the 1964 addendum to the 1963 shop manual). While the results were a huge improvement I was not completely satisfied with the handling at speeds above 45-50 mph. The car "darted" and driving required total attention.

Veteran members (too numerous to list but you -- and we -- know who they are) advised that a C2 with radials will benefit from a different suspension setup. The recommended specs are:
Front:
Caster: +1.5 degrees (but no more than +1.75 degrees)\


Rear:
Camber: negative 0.5 degrees
Toe-in: 1/32" per side; 1/16" split evenly across the thrust center line

Had my car aligned to those specs today ---- the improvement in handling is amazing - it far exceeded my expectations. And for what it is worth, the increase in difficulty of turning the steering wheel at very low speeds that many indicated would be experienced is negligible -- in my opinion, no noticeable difference. The big difference when moving along at highway speed is that steering does not require acute attention, it is a much more relaxed and pleasurable experience.

Bottom Line: The above alignment specs are highly recommended to anyone that has radials on their non power steering C2.

And thanks again to all those that recommended these settings.

[John D.]

Re: C2 Wheel Alignment

Curious as to why the caster would be limited to 1.75 degrees ? Wouldn't a bit more caster help with stability at highway speeds ?

[Duke W.]

Re: C2 Wheel Alignment

Can you post the initial readings before it was aligned to the above specs?

More caster gives better straight line stability, but increases steering effort, which is particularly noticeable at parking lot speed, so it's a compromise, and 1.5 degrees is okay and aided by the fact that radial tires have greater self-aligning torque than bias ply tires.

Having rear toe split equally between both sides is very important to both straight line tracking and equal response to initial turn-in and final dynamic response (understeer or oversteer at the limit) in both directions.

With alignment settings perfectly tuned (which most guys don't pay attention to) and modern radial tires a C2 will have very good stability and steering response with minimal understeer, but grip is ultimately limited by available tires. Most replacement sizes are not designed for maximum
grip, but are "all season" with very hard compounds for long wear, which is reflected in the UTQG wear rating.

C2s have minimal designed in understeer, and even with perfect alignment can transition to oversteer at the limit. This can be mitigated by installing hard urethane bushings in the front anti-roll bar links, which reduces compliance with roll that tends to transfer roll stiffness to the rear, which has less roll compliance thus causing limit oversteer. Another solution is to install the 13/16" front anti-roll bar that was on base suspension C3s beginning sometime in the mid seventies, so they are common.

Duke

[Ed S.]

Re: C2 Wheel Alignment

Curious as to why the caster would be limited to 1.75 degrees ? Wouldn't a bit more caster help with stability at highway speeds ?

John,
If you were to do a search of this subject in this forum's archives you would get about a dozen or so threads that recommend these settings - but among all the recommended settings there is one that varies - that is front caster. Some say go as high as 2.0 others recommend as little as 1.5 --- this is for cars without power steering. And the reason is that more caster makes it more difficult to turn the wheel at a stand still or crawling speeds. I went with 1.75 as a max to be a bit on the safe side - the good news is that it solved the darting problem - driving the car above 50 mph is much more relaxing now.

[Ed S.]

Re: C2 Wheel Alignment

In response to Duke's request to post the readings before the alignment.

Front
Camber: +0.28*
Caster: -0.66*
Total Toe in: - 1/8"

Rear:
Cross Camber: = 0.06*
Total Toe-in: + 3/16"
Thrust angle: - 0.25*

[Mark E.]

Re: C2 Wheel Alignment

Positive camber and negative caster... it's little wonder the car "darted".

Was it set that way, or did the suspension get out of alignment?

[Ed S.]

Re: C2 Wheel Alignment

Positive camber and negative caster... it's little wonder the car "darted".

Was it set that way, or did the suspension get out of alignment?

Got out - initially it was set to factory specs, and it was fine for a while - I don't drive it much and it surprised me that it was out that much from factory.

[Domenic T.]

Re: C2 Wheel Alignment

Ed,
Thanks for the info, I just printed it out for my 67.

Dom

[Ed S.]

Re: C2 Wheel Alignment

Ed,
Thanks for the info, I just printed it out for my 67.

Dom

Dom,
You are welcome. Again, for the record, I did a search on this forum and found a number of threads that addressed C2 alignment with radial tires. All I did was consolidate the recommended settings and posted them. Hopefully my post will save others time as they search for this info. But, I can't take credit for the technical advice. Two members that recommended these were Duke Williams and Joe Lucia, there were probably others - thanks to all.

[Duke W.]

Re: C2 Wheel Alignment

John Hinckley has also recommended the same alignment specs for "touring", radial tires. For "sport" (radial tires) I recommend the same other than running up to negative one degree camber at all four corners with as much positive caster as can be had at that camber setting.

Also, all "cross readings" should be as close to zero as possible.

Duke

[Raymond R.]

Re: C2 Wheel Alignment

I had my C2 aligned in accordance with the specs recommended in Ed Szeliga's initial post. After the alignment, I realized those specs were for a C2 without power steering. My C2 has power steering.

I then found Duke Williams post with recommended touring specs for cars with power steering. The recommendation for front caster is: positive 1.5 - 2.5 degrees, with power steering cars going for the high end of the setting. It was noted that some cars may be difficult to achieve 2 or more degrees.

My C2 front caster was adjusted to positive 1.5 degrees. How much difference would there be if I had them adjusted closer to the positive 2 or 2.5 degrees? Is the difference in steering worth paying to have the care realigned?

[Patrick B.]

Re: C2 Wheel Alignment

Unless you are having a problem with the steering self centering, I would leave it alone. It is well with the GM specs.

[Raymond R.]

Re: C2 Wheel Alignment

Thanks for the reply, Patrick. I appreciate the advice.