Alignment after installing new springs?

[dubster99]

There already is a camber adjustment procedure in place for the S197 for cars that need it, just that it's a little inconvenient. I'm guessing that something similar exists for the S550.


Norm

Where is that adjustment?

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[Norm Peterson]

Briefly, you have to open up one of the sets of holes in the strut to permit adjustment between the strut and the knuckle/"spindle" and use Ford's own camber bolt. The fact that you have to actually modify the strut "ears" is the inconvenience, and there are limits in the Ford procedure as to how far is acceptable to grind the round holes oval.

I expect the same procedure to exist on the new car, no reason I can think of for not retaining it (doesn't even cost any more).

If I can find it in my 2008 factory shop manual I'll try to copy and post it up.


Norm

 

[spoole96]

I have a 15' GTPP with the Steeda sport springs installed. I drove the car around for almost a week before alignment. I got my car aligned today and below are my results. Am I still running to much negative camber in the rear? According to the specs posted on this thread, stock rear camber should be -1.50. My rear wheels still look like they are angled in more at the top than before I installed the Steeda springs. I guess my question is, are these results acceptable for tire duration? I don't mind a little extra wear if the car benefits greatly in handling. But, I don't want to be changing tires every year either. What do you guys think?

 

[dwaleke]

Camber is fine. You won't notice the difference between that and the spec -1.5.

I would want closer to -2.0 up front though.

 

[Ryan1112]

So why would you want -camber in the rear. I understand cornering grip but wouldn't you want that to be zero for traction. When the car squats during acceleration it would cause even more camber causing even less traction. It was zero with the live axle in the s197 so I was expecting it to be the same for the s550 but the IRS would gain camber only under cornering. Sorry, I'm new to this IRS business.

 

[Norm Peterson]

Consider the case of traction for acceleration on corner exit. Ideally, you're operating the outside rear tire at or close to zero camber, but that's the sum of at least three effects. Static camber (what the alignment guy sets), camber gain (what happens to camber as the suspension moves into 'bump', the suspension designer's responsibility), and the amount of cornering roll that's happening (what you're doing) are all involved. It's apparent that Ford is paying a little more attention to the corner-carvers among us than previously. This is certainly consistent with their decision to step back a bit from drag racing - didn't John Force go back to Chevy as a consequence?


Incidentally, there is no hard and fast requirement for live axle camber to be zero. Anything manufactured inherently has tolerances, never mind that a stick axle could be intentionally designed to have a little camber. The axle on the 1979 Chevy Malibu I used to have had rear cambers of -0.5°, and the axle had not been modified in any intentional manner to get there (it also had some rear toe-in).

Stick axles also experience a form of camber gain. Tires have finite vertical stiffness (on the order of 1000 - 2000 lbs/inch), and when load transfers off the inside tire to the outside one the outer tire deflects more while the inside tire deflects less. since the axle and the two wheels have to follow along, this difference in tire deflection ultimately becomes a camber change. This effect also affects the operating camber of independently sprung wheels.


Norm

 

[Ryan1112]

Thanks Norm. Considering that the front camber stock is about -1 then why is the rear so much more at -1.5. It just seems like a lot to me. Also, to get more front end grip for the track I always used about -2.5 with my s197. Would I also increase the rear or just leave it at -1.5?

 

[Norm Peterson]

It appears that Ford is counting on negative rear camber as a means of guaranteeing limit understeer. Maybe particularly because of the tire size staggering.

Unless straight line acceleration has a high priority in your driving, I'd first experiment with front camber and leave the rear camber alone. Maybe not all the way to -2.5° right away, but somewhere past -1.5°. Get a feel for how sensitive the car is to these changes before loosening up the rear.


I do know that what used to be one of the better aftermarket chassis entities over on Camaro5 used to suggest running less than stock rear camber, also for the purpose of reducing understeer in street driven cars (I think it was for their "performance street" level). What I don't have is a good feel for when this stops being the right way to go, but at some point you could be driving hard enough on grippy enough tires to put the outside rear tire clear into positive camber and a desire to lead instead of follow for a change. Might as well crib at least a little from the folks who've already been there.


Norm

 

[Ryan1112]

I can't stand understeer. Nothing worse than the front end plowing forward and chattering during a turn when you're autocrossing. I subscribe to the notion of fixing the end of the car that has the problem first. So I'd rather try to give the front end of the car more grip rather than changing rear camber or putting a huge rear bar on it ro the rear loses grip. I'm mainly wondering if it's 'normal' to adjust it so the front has more -camber than the rear when trying to get a good balance.

 

[Norm Peterson]

I'm mainly wondering if it's 'normal' to adjust it so the front has more -camber than the rear when trying to get a good balance.

Generally, yes. And I think particularly so if the front suspension is some sort of strut arrangement. Camber gain on an outside strut wheel gets slower as that wheel moves in the bump direction, while camber gain on a SLA type of suspension tends to get faster. Good for the OE's and their lowest common denominator customers, I guess . . .


Norm

 

[BmacIL]

I have a 15' GTPP with the Steeda sport springs installed. I drove the car around for almost a week before alignment. I got my car aligned today and below are my results. Am I still running to much negative camber in the rear? According to the specs posted on this thread, stock rear camber should be -1.50. My rear wheels still look like they are angled in more at the top than before I installed the Steeda springs. I guess my question is, are these results acceptable for tire duration? I don't mind a little extra wear if the car benefits greatly in handling. But, I don't want to be changing tires every year either. What do you guys think?

The rear is probably OK (more than -2.0 deg will get you significant tire wear on the street), but would go back and have them get your front right into negative territory (at least -0.5 to -1.0).

 

[Dat Boi Kumar]

I bought 16mm camber bolts to fine tune my front Camber with Eibach Sportlines.

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[Dat Boi Kumar]

Heres my alignment sheet with sportlines for reference.

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[S550_Magnetic]

This weekend I put on the Eibach Pro-kit springs and I went and got an alignment today. I first drove around for 35-40 miles yesterday before taking it to get an alignment. I took it to Firestone and the only thing that was off was it had toe-out on the front.

 

[Norm Peterson]

Got the print-out?


Norm

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