Contour Enthusiasts Group Archives Forums Modifications Suspension Alignment Specs

MFE,
So how much negative toe do you run at front?

-2.5 degrees on those tires. I should point out this particular case is not on a contour, it's on a Mustang. I have a stock suspension on my contour. But I have a GTP lowered to the point of about -1.5 camber on all 4 corners and again, no inside-edge wear issues on that either, because the toe is spot-on.

I need to object to running -2.5 degree front total toe in a rear wheel drive vehicle. It will be tiring/uncontrollable. I have hard time believing that was the setting during your street driving. Please comment.

You can object all you want but that's the setting I'm running as I type. I used to run -1.5 on the street and max it out to 2.5 for autocross events, taking the toe change that came with it, but one time I took it to an open-track event, set it to -2.5 (where I did correct the toe because I didn't want the high-speed braking instability caused by toe-out), and got lazy after the event and just left it there. I've run it that way ever since, with the exception of a 1200-mile round trip on the highway, where I backed it down to -1.5. It's back to -2.5 now and will remain that way. I put over 10k a year on this car. It's no more "tiring" or uncontrollable than any other Mustang.

I'm not objecting to anything. I was agreeing with you. But not all cars can run around with that much camber with no were. Sorry. Thats all

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Camber doesn't really eat tires up unless the toe setting is off (in which case they get chewed in a hurry) or the car exhibits poor toe control.

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I strongly disagree.

Camber is a wear angle. If the toe is off too then you have two things working against tire wear.

I talked to my brother about this some time ago, he was a master front end and brake mechanic. Between conversations with him and reading some of his textbooks and looking into a variety of sources, I totally understand that it's physically impossible for negative camber to NOT affect tire wear due to what's happening to at the interaction between the tire and the surface as the tire rolls.

So, fair enough, it's a fact that camber wears tires to at least some extent (no argument from me), but how do those of you who insist it's a primary wear factor explain the fact that, for instance, I personally have two cars driven 10-15k per year with moderate to excessive negative camber and yet both exhibit virtually even tire wear?

The explanation is, and what I said was, the effect of negative camber absolutely pales in comparison to what happens when the toe is wrong, and if the toe is wrong AND the camber is excessive, look out, bye-bye tires.

Toe is in fact the primary wear determinant, and if it's off, then the camber is a wear accelerant. Not the cause in and of itself. Take care of the toe, take care of any major instability of the toe under dynamic conditions, and the wear will largely take care of itself. Minimize negative camber and you can mask the wear issues caused by toe, but they'll still outpace the wear you'd get with even large amounts of camber if it's tied to proper toe setting and proper toe control.

You can, and I do, run fairly dramatic amounts of camber with no significant wear effects, and toe control is the reason why that is.

i certainly have to agree with you. toe is a major, major wear factor, 90 percent of tire issues are always because of toe. camber does wear, but it does depend on how much camber. the only difference between 0 degrees camber and negative 2.5 degrees is that the weight of the car is riding on less tire. therefore that portion of the tire will wear faster because of more heat and friction caused by improper weight distribution.

Excessive camber, either negative or positive, make the tire want to conform to the shape of a conical section.

Toe is the primary tire wear angle. Unfortunitely too many alignment techs have taken the attitude that all they need to do to set an alignment is "set the toe and let it go". In so doing they all to often miss additional significant problems.

One of the most critical factors to this discussion is that alignment is not a static thing. Alignment is dynamic. The attempt to setting alignment is to somewhat guess at what will end up being appropriate when the car is in motion, not sitting on an alignment rack. Toe changes with road force and drivetrain power. Caster and camber changes as the vehicle bounces up and down and as it corners. Alignment also changes some just from the additional weight load in the car and how it is distributed. One of the most critical lessons taught in a basic alignemnt class is that if you are aligning a car that has a very heavy driver, it is best to have the driver in the car while making adjustments so you can compensate weight induced pull or wear.

So why do you have good luck with some cars with fairly extreme camber settings? I don't know. Maybe you spend most of your driving time taking hard corners at higher than normal speed? Maybe you carry 500 lbs of mountain rescue gear in the trunk that wasn't there when it was aligned? Maybe the alignment gods have taken a liking for you and have given you special dispensation? Whatever it is, I can clearly say that it is uncommon to have so much negative camber and not have tire wear. After all, your tires don't start life shaped like a conical section.