Alignment specs

[firebob]

Doing my own alignment and I have been running - 3/4deg camber but the inside is beginning to wear out. So I thought I would dial it back to 1/4. Just not quite sure whether to set the camber first and then check caster or the other way round. Been awhile since I did it last time. M thinking camber first and then move to the caster. If I do camber first and I have enough caster after I just leave it be but if I need to add more caster then I need to go back and revisit the camber setting. Sound reasonable?



Ok, finished up with the camber. Got it down to -1/4degree. Caster to 3.5. Didn't set the toe. Ran out of time. Toe should be just slightly out(1/4") front of tire to back, right?

[Sleeper68]

Doing my own alignment and I have been running - 3/4deg camber but the inside is beginning to wear out. So I thought I would dial it back to 1/4. Just not quite sure whether to set the camber first and then check caster or the other way round. Been awhile since I did it last time. M thinking camber first and then move to the caster. If I do camber first and I have enough caster after I just leave it be but if I need to add more caster then I need to go back and revisit the camber setting. Sound reasonable?

Ok, finished up with the camber. Got it down to -1/4degree. Caster to 3.5. Didn't set the toe. Ran out of time. Toe should be just slightly out(1/4") front of tire to back, right?

1/4" of toe is a ton!

Many brand new cars are set up with alignment specs that are much more aggressive than you are describing and do not exhibit significant camber wear. My Subaru and Mini cooper both have factory alignment settings over -1deg of camber. I run -3deg camber, +6deg caster, and 0'' toe on my 68 camaro. All of the front tires wear very evenly.

What kills tires with camber is toe. The constant scrubbing going down the road eats the inside of the tire. Severe bumpsteer can also do this.

I suggest you run as little toe as possible, -1.5deg camber, and closer to +6deg caster. That setting SHOULD not eat tires as long as you have corrected geometry to eliminate instantaneous bumpsteer and flatten the bumpsteer curve.

Ryan

[stab6902]

I usually run 1/16" toe-in. Factory spec was 1/8" to 1/4" toe-in, but that was for old school bias plies. I agree that 1/4" toe (out or in) is way too much for a street driven car on modern tires when wear is a concern.

In a perfect world zero toe would make sense, but I figure there has to be a little give somewhere in the suspension/steering linkages when road loads are applied, so I run a touch of toe-in thinking it'll actually be zero when the car is going down the road.

[Chad-1stGen]

As Ryan indicated the Toe is the reason for your bad inside wear. If you are going to drive on the street a lot then toe out is a no no. Either zero toe (for best performance compromise) or toe in 1/16"

Is this a stock subframe? Guldstrand mod, or taller spindle/ball joint?

If you avoid toe out then you should be able to run -1* camber no problem. I'd shoot for -1* camber and 5* of caster if you can get them. Car will handle much nicer that way.

[firebob]

Stock subframe. 1/2" taller upper ball joint. You all may have something with the toe settings. I don't recall being able to set the toe last time so they may have been out enough to wear the inside prematurely.

What is the best way to set the toe in my garage or driveway?

[79-TA]

What is the best way to set the toe in my garage or driveway?

I'm not sure how much background you have, so please forgive me for describing too many of the basics before getting to more details. Perhaps it might be useful to someone else.




The theory is simple. You want the wheels near parallel when viewed from above. You'll use anywhere from 1/16" toe in to 1/8" toe out (for a more extreme auto x focus). Modern radials typically require less extreme settings.

The adjustment is simple too. You either lengthen or shorten the tie rods that go between the steering arms and center link (or rack) until the wheels are (near) parallel.

Be sure to know which way to turn the tie rod to lengthen or shorten the reach. Then, take note of whether your car is front or rear steer to see if shortening will create more toe-out or toe-in.

Loosen the jam nuts. Then, keep track of how many turns or partial turns you make to the tie rod. Make sure the jam nuts don't prevent you from making your desired adjustment. Make the same (shortening or lengthening) change on both sides to keep the steering wheel centered. Continue to guess and check until you hit your measurement. When tightening the jam nuts, make sure to move the nut and hold the tie rod end steady so that the length isn't accidentally adjusted.

If the steering wheel is not centered to your satisfaction, set the toe first. Then make small changes to both tie rods, but this time lengthen one, while shortening the other the same number of (partial) turns. You won't really know how well the steering wheel is centered until you test drive the car.

The front is much more forgiving than the rear in this regard. Instead of creating a dog tracking condition, the steering wheel will just be slightly off center. And since we're talking about solid rear axle muscle cars, most of us never need to touch the rear suspension alignment.

The hardest part is being able to measure accurately.
The following things can make the measurement difficult:
- Tire bulge (lower profile tires mitigate this problem)
- Imperfect measuring locations
- Objects underneath the car getting in the way of the tape measure (lower profile tires also mitigate this problem)
- Tires sticking on the ground and the suspension not settling after being lowered from a jack
- Forgetting your exact reference point(s)

To measure in my driveway, I use the following equipment:
- One tape measure with clear 1/32" marks (it matters more that the reading is consistent than accurate)
- two 4x4 pieces of wood
- Magazines or plastic bags to act as grease plates under the tires
- two straight edges - I like angle iron or thick sheet metal bent at a 90° angle
- one friend or family member (I think I've recruited almost everyone in my family at some point)

If you have grease plates, use them under the front tires, but I usually use magazine pages or plastic bags to allow the wheel to slip and settle on the concrete. Bounce the car a couple of times to help the suspension settle.

I set the 4x4's next to each tire. Their only purpose is to hold the straight edges at a fairly consistent height from one side to the other. Set the straight edges on the 4x4's and push them into the wheel/tire. Make sure they sit nice and flat on both sides with no bulges or protrusions making them unstable. I am unable to use this method for the 245/60/15 tires on my Trans Am, but it works fine for the larger 275/40/17 tires or the smaller 195/50/15 tires on my Miata.

Have a friend hold one straight edge still while also holding the end of the tape measure on the edge of the straight edge. Agree where to hold the tape relative to the tire to avoid measuring diagonally. Make sure the tape is not being bent by any interfering parts under the car.

You'll be the one reading the tape measure, so make sure you have a consistent viewing angle of the tape above the determined reference point on the straight edge. I like to use the sharpest edge available on the straight edge. Consistency matters more than accuracy. Repeat the process for the other side of the tire.





Alignment kits like the quick trick system are neat in that they give you a nice consistent and solid measuring locations that are low to avoid under-car obstacles.

[firebob]

Thanks for the ideas and info/explanations. I ended up at about 3.5 caster/1/4 degree neg camber/0 toe. Ill run like this for awhile and see how it feels. If it starts to wander maybe I'll add a little toe-in.

[David Pozzi]

If your caster is correct, then it won't change when you shim for camber IF you change shims using the same thickness on the front and rear bolt.

[firebob]

What's the sequence of making the settings. Caster then Camber then Toe? My guess.

[David Pozzi]

Yes, if doing a re-alignment. If it's after replacing a whole bunch of new parts, then I still do it in that sequence but I do have to go over all settings a few times. You can't set camber if toe is off for example. Toe doesn't have to be perfect but it has to be pretty close. Camber readings change if you turn the wheel a few degrees. Caster is a difference between turning the wheel in and out so it is not affected by toe.

First gen suspension has some bump steer. If the front of the car settles, the wheels toe out, so over time your front suspension get's lower and that causes extra toe out from the bump steer.