Looking for Alignment Spec recommendations

[brusk]

I'm trying to make sure my car gets aligned properly to match my driving. Unfortunately this requires a little back story. I added M3 rear subframe bushings 6K miles ago along with the front M3 Control Arms. Took it to Cobb Tuning in Plano and afterward it would pull to the right at WOT and pull to the left when letting off the throttle. Recommendations where to replace the rear tow link and camber link. I did with Rogue and M3 parts.


2nd Alignment felt better and I didn't notice any issues until increasing power from OTS 2+ to an E40 blend then it was controllable but very lively at WOT. Fast forward about a year and 6K miles later the car was starting to be uncontrollable at WOT on the highway constantly veering right then left and repeating every time I would slowly correct it. It would look like you were purposely swerving from line to line in your lane. I decided to check all my rear suspension bolts for tightness and noticed the very inside rear tires are showing metal with only 10K miles on them. I've bought new rear tires, ECS rear trailing arms and M3 rear upper control arms. Now the only stock part in the rear is the lower control arm.




Mods in signature. What specs should I give the alignment shop this time. I drive mostly highway (highway pulls) and some mild aggressive back road driving so I was thinking less Camber and medium on the Toe. Also the fronts are wearing a little more on the outside than the inside so I think I can go more camber in the front.

Edit: 2/17/15 Had wrong 2nd Alignment pic

[Pig Farmer]

The tire wear in the picture is likely the result of the -toe (i.e. toe out) on the right rear wheel, and to a lesser extent the -camber. The -toe in the rear and essentially zero toe in the front explains the unpredictable feeling on the highway. Since you're looking for a little more stability, I'd shoot for 10 degrees of +toe on each rear wheel (20 degrees total +toe) and five degrees of +toe on each of the front wheels. You should try to max out the negative front camber, but I find you can actually reduce the negative camber in the rear and still have plenty of grip... -1.4 degrees of rear camber is plenty for the street, and can actually result in a more balanced car.

[brusk]

Originally Posted by Pig Farmer

The tire wear in the picture is likely the result of the -toe (i.e. toe out) on the right rear wheel, and to a lesser extent the -camber. The -toe in the rear and essentially zero toe in the front explains the unpredictable feeling on the highway. Since you're looking for a little more stability, I'd shoot for 10 degrees of +toe on each rear wheel (20 degrees total +toe) and five degrees of +toe on each of the front wheels. You should try to max out the negative front camber, but I find you can actually reduce the negative camber in the rear and still have plenty of grip... -1.4 degrees of rear camber is plenty for the street, and can actually result in a more balanced car.

Cool good to know. Also both rears wore exactly the same this way.

[Dmak]

2nd alignment looks not bad, but looks like they are too lazy to touch the front camber. what tire pressure are u running at the rear? can try playing with pressure. can set it slightly higher for high way drive.

[brusk]

went and got new tires put on and an alignment. Unfortunately I didn't want to drive far with the tires that bad so I went with a reputable local tire shop. Told him my problems and showed him the previous alignment and the recommendation. Here's what he set it at, any thoughts on it, I wish he would have went with less rear camber I told him not sure if that's all he could get or what. Just hoping it doesn't wear the rears out again. And since it's friggin snowing/icing I have no idea if it helped my stability, guess I'll find out in a few weeks.

[dbronnik]

How did your camber change so much between your 2nd and 3rd alignment (your 3rd alignment says -3/-2.5 in the rear in the before measurements..) Did you have a couple bodies in the trunk ..??

FWIW I've recently changed my alignment 4-5 times and finally settled on these specs -- it might be a bit too twitchy for you if you set your front toe as I have though, so I'd recommend 0" toe or even 0.05" in the front if you really want that stability:

Caster Front Left: 8.7"
Caster Front Right 8.2"

Camber Front Left: -2.4"
Camber Front Right: -2.4"
Camber Rear Left: -1.9"
Camber Rear Right: -1.9"

Toe Front Left: -0.05"
Toe Front Right: -0.05"
Total Toe Front: -0.15"
Toe Rear Left: 0.05"
Toe Rear Right: 0.05"
Total Toe Rear: 0.10"

Thrust Angle: 0"

[MightyMouseTech]

Negative rear toe will cause both the instability and excessive wear on the inside of the rear tires. Makes a MUCH bigger difference than camber. Although, if you have high negative camber AND negative toe, you are basically dragging the inside of the rear tires down the road.

Your last alignment shows 0.28 total toe in the rear, that should be good for tire wear. The more toe in you go, the better for stability and wear. If you have it aligned again, you may even want to set it to the most toe in you can get within spec, or 0.20/wheel for a total of 0.40.

[wildacex187]

Originally Posted by MightyMouseTech

Negative rear toe will cause both the instability and excessive wear on the inside of the rear tires. Makes a MUCH bigger difference than camber. Although, if you have high negative camber AND negative toe, you are basically dragging the inside of the rear tires down the road.

Your last alignment shows 0.28 total toe in the rear, that should be good for tire wear. The more toe in you go, the better for stability and wear. If you have it aligned again, you may even want to set it to the most toe in you can get within spec, or 0.20/wheel for a total of 0.40.

Do these specs have a negative effect on rear handling performance?

[MightyMouseTech]

Originally Posted by wildacex187

Do these specs have a negative effect on rear handling performance?

It will make the rear end more stable. It is still within factory specs.