Wheel Alignment C4 Corvette - What's An Alignment?

Keeping Your C4 Corvette On The Straight And Narrow.

Richard F. Newton Dec 1, 2000 0 Comment(s)
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During the past few months I've tried every possible wheel alignment setting on my C4. You have to understand that at we at Team VETTE try to take a perfectly good Corvette and push it past all the limits. The idea is to take our own Corvettes and keep going until we really screw them up. Boy, did I do that.

I finally found an alignment setting that was fantastic on the race track. The only problem was that my old white '85 Corvette became undriveable during morning and afternoon commutes. I fully demonstrated that what is good for the track is not very good at 65 mph, and it's even worse at 40.

There are two very important things we need from our '84-96 Corvettes. First, we want the car to go down the road in a straight line. Secondly, we want those big expensive tires to last as long as possible. These goals are the same for the street or the track. How we get there, however, is a whole different situation.

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Proper alignment is absolutely essential for maximum traction and high-speed performance, not to mention optimum tire wear The one thing that makes all this possible is a quality four-wheel alignment. The only time you should need an alignment is when something causes the wheels to move from the last time you had an alignment. A giant pothole could cause something in your suspension to shift. Also, wear in the steering components could cause all the settings to change. (In our case, we just kept screwing with the settings every time we put it on the track, but that's a story for another day.)

The problem is that suspension and steering components wear gradually. The aforementioned pothole damage is something you'll notice immediately. Accumulated wear, on the other hand, is something you'll adjust your driving style to. It's not until someone else drives the car that the poor alignment becomes readily apparent.

An annual preventive maintenance alignment will tell you if anything has changed. If it has, some usually minor adjustments will put you back in business. If you wait until you actually feel a change in the steering, or notice a high-speed wander, some serious changes have already taken place, and the repair bill will test the limits of your Visa card.

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Vette Brakes makes a handy lower adjustable strut rod for '84-96 Corvettes. The real beauty is that you can adjust your camber anytime you want-if you have a tool to measure camber. This means that you can use one camber setting for track events and another for the Monday-morning commute to work.

There are several ways to decide if an alignment is really necessary. First, check the tread depth of your tires on a regular basis. Uneven tire wear is a dead giveaway that your Corvette needs help. All four tires should wear evenly across the tread. There shouldn't be any difference in the wear on any corner of the Corvette, or across the tread of any given tire. Anytime you notice excessive tire edge wear, beware-you have an alignment problem.

Another dead giveaway is having to steer your Corvette constantly while you drive down the road. Any Corvette, of any year, should go down a straight road without steering input. Steering wander at highway speeds is a definite sign of a problem. It might be because of accumulated chassis wear, but it's a sure sign that your wheels are not pointed in the appropriate direction.

Where Do You Go For An Alignment?

Finding someone to align your Corvette is getting to be a major problem. There are very few people left in the service industry who can align a Corvette properly. I used to train technicians, and only about 10 percent of the people who claim to be alignment specialists have any real knowledge of what they're doing. It takes a certain amount of intelligence, and a lot of experience, to do the job properly. Very few shops can attract and hold this type of service technician.

There's no special type of service center that's better than another. Your Corvette needs an outstanding alignment specialist, whatever type of shop they work in. They might be at a local tire center, or at an independent garage. You might even find one at the local Chevrolet dealership. It isn't that the Corvette is so difficult to align-it's just that most of us are very picky about the way we want our Corvettes to drive.

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The front suspension settings on C4 Corvettes are changed by swapping shims. Keep in mind that the shims go between the tower and the cross shaft.

One way to identify a quality shop is to determine the type of equipment that's being used. You don't need the latest wiz-bang equipment to do the job properly; you simply need equipment that's well-maintained. Alignment equipment is very fussy-it needs to be well-treated. A bad technician will abuse the equipment, and the shop owner, who's tired of paying repair bills, will let the equipment go to pieces. You want to avoid a shop where this is taking place. Remember, a clean organized shop is a good shop.

The newest alignment equipment is designed to do two things. First, it has to be extremely easy to use. Most good technicians work on some sort of commission, and the time it takes to set up and align your Corvette has a direct impact on how much money they make each day. The latest equipment won't let them do a better job on your Corvette; it'll simply let them do it faster. At the end of the week, both the shop owner and the technician will take home more money. There's nothing wrong with that if your car gets aligned.

The second point to consider is that the latest equipment is designed to make up for the lack of skill that most alignment specialists bring to the job. The problem is that no amount of sophisticated equipment can make up for a technician who doesn't even understand the difference between caster and camber.

This doesn't mean that you want to visit a shop that has 20-year-old equipment-but on the other hand, don't be seduced by the latest CD-ROM alignment machine. Remember, it's still the operator of the machine that makes the actual adjustments, not to mention deciding what is finally good enough for your Corvette.

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The upper control arms on C4s may be the strongest part of the car. Spherical washers of several different thicknesses of were used during the time the C4 was in production.

My favorite piece of equipment not only tells the technician what's wrong, but it tells them which bolt to turn to bring the car into specification. The screen is full-color VGA, which provides a very accurate image. The only problem is that this new technology is too often used as a substitute for training.

The best way to find a shop is to ask around. There are always enough Corvette owners in your neighborhood to ask where they got their car aligned. It's the old "ask the person who owns one" approach. In every community there's at least one good alignment specialist. Your task is to find this individual.

The next item is to make sure that you get a "before" and "after" readout from the computer. This printout is simply a statement claiming that they actually aligned your Corvette the way you specified. Pay special attention to the caster and camber readings. Make sure that they've changed.

A lot of production shops will do what's known in the industry as "toe and go." This is simply adjusting only one of the three major alignment settings. A "toe and go" takes only 15 minutes, while a complete alignment might take an hour. There are ways to cheat on the computer to give you different before and after readouts without ever putting a wrench on your Corvette. However, we won't get into that here. Remember, find a good shop. That's your only protection against consumer fraud.

What's the Terminology Mean?
Chances are you're going to hear a specialized vocabulary thrown at you. This can be pretty intimidating. Hey, there are times when the service writer uses all these words specifically to intimidate you and soften up your sales resistance-don't let it fool you.

Toe: The first word you're going to hear is "toe." All this means is how straight the wheels go down the road. Think about this for a minute: You want the right front tire going down the road parallel to the left front. And both of them should be parallel to the center of the Corvette. In an ideal world, all four tires will be parallel to the center line of the Corvette as you drive down the road.

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If the wheels are cocked in toward the center, we say that the wheel is "toed-in." If the wheel is cocked to the outside of the car, we call it "toe-out." If your left front tire is pointing too far to the outside, it'll wear out quickly and slow the car. Most of the tire wear problems that you see on Corvettes come from improper toe settings.

There are times when you actually want some toe-out, but we'll get to that later. These toe numbers are usually given in degrees. Sometimes the number is given in inches, but that's the older system that was used before the computer age.

The rear toe specification of the rear wheels is just as important as for the front wheels. Just as you don't want to have the front wheels running down the road pigeon-toed, you don't want the rear tires doing the same thing. Remember, ever since 1963, the Corvette has been adjustable on all four corners.

Caster: Caster is a very important specification, since it determines how well your Corvette goes down the road in a straight line. You usually won't get poor tire wear from incorrect caster, but you will have steering pull.

A basic rule of thumb is that the more caster you have in your Corvette, the easier it is to drive in a straight line. A lot of caster gives you directional stability. An interesting point here is that Chevrolet increased the caster specification from '84 to '85, and again in '86. The same thing was done very early in the C5 production run. It seems that the Corvette engineering group always starts out with a minimum amount of caster, and then increases it as they gain experience.

The engineers were searching for that elusive balance between high-speed stability and steering effort. I see no reason why you simply can't use the 6.0-degree specification for your earlier C4. I was able to set my '85 up with 5.9 degrees of caster.

This is the only setting that stays the same for a track car and a street car. There's really no downside to using a lot of caster on a street car. Lots of caster will increase steering effort, but the Corvette uses power steering, so how would you be able tell?

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Camber: The next important item is the camber of the wheel. Remember, the goal is to put as much rubber as possible on the road at all times. Now think about going around a corner. You want the wheels vertical to the pavement as you take the corner. This means the static specification will call for the wheel to either tilt in or out, depending on the chassis design. The C4 factory specifications call for a slight outward tilt, or positive camber, while the C5s use a very slight negative camber-the top of the wheel is tilted inwards.

If you add more negative camber, or tilt the top of the wheel in, the car will handle better on the track, but also wear out tires faster. You're looking to get as much tire wear as possible, and you have to decide how many sets of tires you can afford. Generally, the Corvette likes factory specifications. When you change from the factory specifications, you should have a good reason. You should also be aware of what this change will mean in normal driving.

The '84-96 Corvette doesn't allow a lot of negative camber. On the track it would be nice to run about 2.5 to 3.0 degrees of negative camber. The most you're going to get out of a totally stock Corvette is about 1.8 degrees.

The problem is that this isn't quite enough for the track, and a little too much for comfortable street driving. The old Corvette Challenge Corvettes were getting 2.6 degrees of negative camber on the front suspension. If you think you can do this with a stock Corvette, then you still believe in the Easter Bunny. The old World Challenge and Corvette Challenge Corvettes had some really trick lower suspension arms that no one wants to talk about.

What Are the Correct Specifications?
The problem with giving you a set of alignment specifications here is that they might take up the entire magazine. No matter what alignment equipment your shop uses, they will have all the specifications stored on the hard drive of the alignment machine.

The other option is to find a factory manual for your Corvette. Copy the alignment numbers from the manual and tell the alignment shop that you want this set of numbers used. If it's different from what's stored in the shop's computer, they might tell you they can't be responsible for the work. That shouldn't be a problem.

Anytime you develop a set of alignment specifications you have to assume some responsibility for them. I understand that if I want something different from what the shop normally uses, I also have to assume the responsibility for the results.

This is particularly the case when you start changing tire and wheel sizes. Remember, the Corvette rests on its tires. Change the tires and you usually change the ride height of the car. Change the ride height, and you change the way the wheels point. Now you're on your own.

The Yellow Stripe TrickI learned this one from working on race cars, but it works just great on street cars as well. Get some very bright yellow paint and a small paint brush. Now make a yellow strip over all the alignment settings. This way you can tell if anything has loosened up. This is especially important on the rear alignment setting.

The other thing that it does is tell you if the alignment shop has actually changed anything. The most common rip off in the industry, as we mentioned earlier, is to do a "Toe and Go" when the customer has paid for a full four-wheel alignment. Since the most common problem is front toe, all the shop does is set the front toe and send the car out the door. You just paid over a hundred dollars and got the $49.95 special. This goes on a lot more than we like to think about.

New Rubber For The X-S CorvetteI found out one very interesting fact during my last outing at Sebring. If you lock your brakes up at 125 mph, you create great big flat spots on your tires. We're talking the sort of flat spots that you could put a carpenter's level on. If you've only heard Ned Jarret on TNN talk about how a driver has flat-spotted his tires, you have no idea how bad this can feel as you drive down the road.

The only solution is to get a new set of tires. I went back to the Michelin Pilots. I had a set of the previous version, and loved them. When it came time to create the new generation, Michelin took a little bit of the performance out of the tire and improved the ride comfort considerably. Keep in mind that this was already one of the best riding Corvette tires on the market.

This is a premium tire for Corvette owners who are seeking maximum street performance. There may be better tires for the track, but that's not the point. I need a tire that won't beat me up on the way to work every morning. Besides, how often do you need to surpass 1g on the way to work? I want a nice quiet tire that gives outstanding performance under the magic 1g limit. These new Michelins are great for me. Besides, I don't intend to lock up the brakes at 125 mph on the way to work. Flat-spot these guys, and your wife will wonder what happened to the limit on the family Visa card.

Richard Newton has written two best-selling Corvette books:. How to Modify and Restore Your Corvette: 1968 to 1982 and Corvette Restoration Guide: 1963 to 1967. These are both available from Motorbooks International at (800) 826-6600 or www.motorbooks.com

*The right front may not go to 1.1 without some work on the washer between the pivot arm and the shaft and the frame.

**These specifications are from T.P.I. Specialties, (612) 448-6021.

***These specifications are from Chevrolet and were the intial specs for the '88 Corvette Challenge. If you use these settings on the street your Corvette will be almost undriveable. If you stay strictly on the race track, you'll love them. I included them just to show you the difference between a race car and a street car.


Smart Racing Products
Campbell, CA
Vette Brakes & Products
St. Petersburg, FL
(800) 237-9991


How To
Check out the proper wheel alignment for your C4 Corvette, or other Vette, and learn how to properly align it on your own. Deta...
Richard F. Newton Dec 1, 2000


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