1996 wheel alignment

[Paul M.]

i just put new Goodyear Eagle F1 GS D3 tires on my C4 1996 CE and had them balanced and tire pressure set at 32 psi. Had a wheel alignment done to factory specs and the car fades to the right. Any help out there!!! The place I brought my car is brand new with a new wheel alignment machine and master mechanics. I will bring my back to them to redo the alignment. Is there any info that will help?

[Terry M.]

Re: 1996 wheel alignment

Generally GM (and likely other manufacturers as well) have alignment specifications that are broader (wider) than we might prefer. There are several reasons manufacturer's do this, but trying to please all the customers (cruisers as well as auto-cross or track enthusiasts) is probably among those reasons. Did the alignment shop give you a print out of the before and after settings on your car? Did they ask you what type of driving you do with your Corvette?

Modern alignment equipment has manufacturer's settings in the hard drive and unless the shop is performance oriented the technician will set the car to get all the lights green. That may or may not suit your style of driving, and while within manufacturer's specifications those settings may not be accurate (equal on both sides).

Most manufacturers specifications are designed for the car to drift to the right (curb) for driver safety in the event you fall asleep. Most roads are built with a crown for drainage and to lead you to the curb for the same safety reasons. You used the term drift. I take that as different than a "pull." It is in my book, so we need to be specific in our descriptions.

I know for C6s there are alignment specifications on the Internet that are different for touring, full time track use, and part time track use. I expect (there I go assUming again) that there are similar purpose defined settings for C4 as well. Or at least I expect those C4 settings where there when C4s were new -- and things on the Internet last forever, Right?

[Bill H.]

Re: 1996 wheel alignment

I know for C6s there are alignment specifications on the Internet that are different for touring, full time track use, and part time track use. I expect (there I go assUming again) that there are similar purpose defined settings for C4 as well. Or at least I expect those C4 settings where there when C4s were new -- and things on the Internet last forever, Right?

Most guys use these: http://www.vbandp.com/index.php?opti...man&Itemid=148 And what Terry said is right and we could use a better description.

[Paul M.]

Re: 1996 wheel alignment

Thanks Terry and Bill for your info. Terry I'm getting my car ready for my PV certification at Kissimmee in Jan. 2014. To answer your question yes it fades to the right not pull. As you know during that test while doing the driving portion I have to take my hands off the wheel, so I want it as perfect as possible .Paul (55025)

[Ed N.]

Re: 1996 wheel alignment

Paul, I checked my specs book for the C4's and the alignment setting does not specify different alignment specs for touring or track settings. It just saids "Wheel Alignment." Paul, maybe the shop may have a touring setting for the alignment specs. Terry brings up a smart point of getting a before and after print out. I guess the purpose behind that would be in the event that all else fails, the settings can be aligned to the previsous specs?

Terry: Am I off base with the above rationale?

[Terry M.]

Re: 1996 wheel alignment

Paul, I checked my specs book for the C4's and the alignment setting does not specify different alignment specs for touring or track settings. It just saids "Wheel Alignment." Paul, maybe the shop may have a touring setting for the alignment specs. Terry brings up a smart point of getting a before and after print out. I guess the purpose behind that would be in the event that all else fails, the settings can be aligned to the previsous specs?

Terry: Am I off base with the above rationale?

Yes, Ed that is one use of the before and after print out. Another would be to see the values of the after settings to see how close to the mean (center) of each + or - range the car is set to. Some techs to beat the clock will just set it to be within the range (light turns green) and let it go.

My experience with wheel alignments is limited relative to someone who does it each and every day, but I found I always needed to take the car off the rack for a test drive before I was sure the steering wheel was centered and the car ran straight ahead. I also had to find a dead level stretch of road to be sure running straight was assured. When I was doing PVs I had to take account of road construction and local conditions when asking the owner to drive “hands-off” and also apply the brakes. More often than not I gently placed my hand on the steering wheel during these maneuvers. I felt safer doing that, but others may have a different MO.

While not a Corvette observation, the following is a LASA (Long Arm, Short Arm) observation. I was able to get my Caprices to track dead straight in highway cruising by adding as much positive caster (upper ball stud to the rear of the lower ball stud) as I could -- in the range of 6 to 8 degrees and IIRC that is double the factory setting. Without power steering this would not be a good thing, but with PS it allows the car to run dead straight (all settings being centered in the allowable tolerances on both sides, and all parts brand new). This of course puts the caster measurements beyond the factory specifications. My experience at almost a quarter million miles on each sedan is this does not cause advanced tire wear, but of course the tires on the Caprices are not nearly as wide as those on the C4 and newer Corvettes. I have/had the luxury of doing my own alignments, so all I was out was time and labor if it didn't work. I arrived at these settings by some trail and error, but I also followed the advice of those who autocrossed these barges back when (some still do).

Please don’t take this to mean I advocate altering the factory alignment settings on your Corvette, but that might be something you want to consider. I have my flame suit on for those who will be critical of the suggestion that we have to modify our cars to achieve an award. I did not have to do any modifications to my 1970 to pass PV, but I was involved in preparing a 1974 for PV and we had to make the fresh air door on the hood work because as the car left the factory, 3K miles before, it did not work. So we had to chose to present it as delivered and fail PV or fix it and pass.

[Terry M.]

Re: 1996 wheel alignment

Dave,
After reading your post it occurred to me that I had not considered tire wear/differences in my response. If the front tires can be swapped side-to-side (I am not sure about some of those C4 wheel/tire combinations) it might be interesting to see if the drift changes with the tire change.

[Ed N.]

Re: 1996 wheel alignment

Terry, in Paul's case it would not impact him, since the tires are brand new. Also, the tires can not be rotated side-to-side.

[Terry M.]

Re: 1996 wheel alignment

Even brand new tires can be mismatched or have belts misaligned, and I thought it might just be a quick and easy test, but if it can't be done it doesn't matter. Dave has offered an excellent description of the front alignment mechanics. Even with consulting my textbooks I could not have done nearly as well. Take the car back to the shop and find out how good they really are. And this time get the before and after print-out from them.

[Terry M.]

Re: 1996 wheel alignment

Terry: Thank You for the comment. Coming from an educator such as yourself it's humbling. I don't remember where I read or first heard the "ice cream cone" comparison for explaining Camber behavior regarding pulling or lead. It was some time ago. I have used it many times since when explaining the relationship between Camber and vehicle lead. I've seen eyes brighten and the ah-HA moment when the guy gets it right after using the ice cream cone comparison in the discussion. Remember it. It works as a teaching tool. DP.

I had never heard it before and I will use that analogy. If you could have seen through the computer you would have seen my eyes light up - or at least one of them. It also makes graphic why excess camber wears the inside edge of tires.

[Paul M.]

Re: 1996 wheel alignment

Thanks everyone for your knowledge the car is going into the shop Monday. We'll see

[Ed N.]

Re: 1996 wheel alignment

Actually they can be rotated side to side for testing purposes while chasing a lead problem. But you shouldn't leave them that way for aesthetic and wet-traction(directional) reasons..

BUT. Unless its a 96 Grand Sport that has 315 tires and 11" wheels on the rear, you CAN rotate front to rear on the same side. And leave them that way. :grin:

Dave he has 255's in the front and 285's in the rear.

[Bill H.]

Re: 1996 wheel alignment

Hmmm. I stand corrected. I wasn't aware that the tire section width and aspect ratio was different on any 96's other than GS. learn something every day. Late C4's are weird. Refined, but weird.

Good post Dave, I'm not sure on 91' and earlier bit in 92 the tire size was square, 275's all around, there was some customer complaints of the cars tracking on bumps and ripples in the road so they narrowed up the fronts a bit. In 93 the changed to 275/285 or 275/315's. I agree with the castor 4-5 max. more just isn't necessary (in you're going on the track less is better). For street driving, 0 degrees castor is good for tire wear, I run .25 neg. which helps maintain the tire contact patch in the corners and doesn't produce much inside wear (the tires are shot by the time you get significant inside wear). And yea, 1/32 toe in will put the tires dead straight when you are moving. The pulling to the right, I'd take the car out on a back road with no other cars around and drive it on top of the crown, in the center of the road before doing any adjustments.