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Discussion Starter · #1 ·
Can someone please post alignment specs for a 2011 e90 328i w/ sport package (sedan)?

I have had a lot of problems with ride quality/stability and it seems the dealer has changed the SAI by 2 degrees, which helped.

Does SAI specs of 15*14' L and 14*0' R (changed from 13*25' or so each side) mean damage?

It seems the SAI tolerances for an e92 are only 0*30' +/-?

Any thoughts on standard SAI settings? Thanks!
 

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Bad Lieutenant
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Sorry man, I have the TIS up to 2008 or so, and I'm not sure if the specs had changed.
 

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Just another Gear Head!
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This probably needs a short lesson in alignment terminology so I will give it a shot as I did alignments for many years in what seems like a previous life now.
The common angles we all know and love are Caster, Camber and Toe. I will not go into those unless you ask. The other two angles on the front that can be checked with modern computer equiptment are Steering Axis Inclination (SAI) and Included Angle. To envision SAI you need to mentally draw a line from the top of the Strut (or Upper Ball Joint on other designs) down through the lower ball joint. Included Angle is this angle plus or minus the Camber angle depending on whether the manufacturer specs positive or negative camber. (most are positive) SAI and included angle are diagnostic angles for damaged vehicles. If Camber measures way off and SAI is OK then you have a bent knuckle or strut. If Camber is way off and SAI is way off but Included Angle is normal then you have a bent lower control arm or frame damage. Hopefully that makes sense. So if your stated SAI angles are correct you have damage somewhere. The reason I say IF your stated angles are correct is that SAI is notoriously hard for inexperienced techs to measure. The suspension must be supported level and the tires swung through the steering range without weight on them. Hope this helps. Feel free to ask any other questions if you need me to elaborate.
 

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Discussion Starter · #4 ·
bwilla,

Thanks. The SAI readings are as correct as I think they come, a BMW regional engineer came and supervised the work that was performed because of my complaints.
So in your opinion SAI readings of 15 degrees 15 minutes (L) and 14 degrees 0 minutes (R) [changed from 13.40 L and 13.11 R] indicates some sort of damage? Any ideas on what?

Thanks!
 

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Just another Gear Head!
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bwilla,

Thanks. The SAI readings are as correct as I think they come, a BMW regional engineer came and supervised the work that was performed because of my complaints.
So in your opinion SAI readings of 15 degrees 15 minutes (L) and 14 degrees 0 minutes (R) [changed from 13.40 L and 13.11 R] indicates some sort of damage? Any ideas on what?

Thanks!
I would love to see the rest of the alignment readings before drawing any conclusions as there is a relationship between SAI and Camber. Also to be fair a visual examination is going to be essential but in general, yes, something appears to be wrong structurally if those SAI readings are correct.
 

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Just another Gear Head!
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OK, A couple of questions about this vehicle.
Have you had it since new or did you buy it used?
Any history of accidents or other issues that would be relevant?

The printout is a little tough to draw conclusions from . The Camber, Caster and Toe really don't indicate any major issues. This draws the SAI readings into question in my book. Also there is no Included Angle from this machine to help us diagnose. If the SAI is this far out there should also be Camber problems unless someone has corrected the Camber by other means and ignored the underlying issue. Which is why I ask about the history of the vehicle.
 

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Discussion Starter · #9 ·
This car was bought brand new from a BMW dealer a couple of months ago.
Dealer has never been able to align it right. Car very unsteady and pulls - they have told me it is 'normal operation.'

This time the car is finally stable, but to get it there they had to push the SAI nearly 2*. Your thoughts? Thanks a lot.
 

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Just another Gear Head!
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According to this sheet

http://www.bimmerfest.com/forums/showthread.php?t=378625&page=2

SAI is supposed to be 14 degrees 7 minutes. But the most important thing is that SAI be even side to side. The strange thing about your readings is this "before measurement" and "after measurement" nonsense. I can't make heads or tails of that. How do you have readings before measurement? I actually suspect that the first readings where your SAI is acceptable are the correct ones and the after measurement ones are inaccurate. SAI, I feel confident, is not a problem on your vehicle. Furthermore you don't feel SAI only Camber Caster and Toe. Now you did have some toe out that needed to be corrected and that can make your car feel weird and cause it to bump steer. Hopefully they corrected that for you. Also I bet your tires wore pretty good on the inside edges and probably got cupped in the process.

I really don't see anything to worry about with your alignment. Cheers!
 

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Discussion Starter · #13 ·
That sheet is from an e92 (coupe) so I am not sure it is completely right for my car (although the tolerances of 0*30' are instructive).
Assuming SAI is as stated on the "after" measurement, would that over 1 degree difference between the two be sufficient to hide a caster or frame problem?
Thank you thank you.
 

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detour in Ingolstadt
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I know a lot about alignments for cars that are lowered. You can ask for two types of alignments: one that preserves tire life, or one that increases handling. I always told my installer to go aggressive because I had 17" tires and they were cheap.

I preferred slight toe out in front or 0 toe, 3/8 total toe in at the rear, at least -1.0 camber up front and matching -1.0 camber in back. For racing, I had this dialed to -2.5 up front and -2.0 at the rear. I think the biggest way to get this car to handle better is to make sure to not let the rear camber exceed the front. BMW naturally sets it up like this on nearly all of their models. For caster, go with whatever factory says. 7 degrees IIRC.
 

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This probably needs a short lesson in alignment terminology so I will give it a shot as I did alignments for many years in what seems like a previous life now.
The common angles we all know and love are Caster, Camber and Toe. I will not go into those unless you ask. The other two angles on the front that can be checked with modern computer equiptment are Steering Axis Inclination (SAI) and Included Angle. To envision SAI you need to mentally draw a line from the top of the Strut (or Upper Ball Joint on other designs) down through the lower ball joint. Included Angle is this angle plus or minus the Camber angle depending on whether the manufacturer specs positive or negative camber. (most are positive) SAI and included angle are diagnostic angles for damaged vehicles. If Camber measures way off and SAI is OK then you have a bent knuckle or strut. If Camber is way off and SAI is way off but Included Angle is normal then you have a bent lower control arm or frame damage. Hopefully that makes sense. So if your stated SAI angles are correct you have damage somewhere. The reason I say IF your stated angles are correct is that SAI is notoriously hard for inexperienced techs to measure. The suspension must be supported level and the tires swung through the steering range without weight on them. Hope this helps. Feel free to ask any other questions if you need me to elaborate.
What do you make of this alignment where the camber is on but the SAI and set back are off? The dealer said don't worry about it as long as the other specs are in. Tires wear fine except for some heal to toe feathering that I get on every car (especially bmw) that I have ever owned. I can control this with rotations. Thanks for the help.
 

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Just another Gear Head!
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Frankly I wouldn't worry too much about the "absolute" number of SAI as much as whether it is even side to side. This is what tells you if your chassis is "square". Your alignment readings actually look pretty darn good. Keep in mind that the set back is only, what, 20 minutes? That is a very small amount. If you have a bunch of setback you would typically find Caster problems. Think about the wheel hitting a curb straight on and shoving the wheel back in the fender causing set back and straightening up the caster angle in the process. Having an SAI problem you would expect to see Camber problems along with it. But typically that would be an SAI problem on one side as if you had hit a curb perpendicular to the wheel by sliding and steering away from the curb. Hope that makes sense.
 

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Rest in peace, Coach
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That sheet is from an e92 (coupe) so I am not sure it is completely right for my car (although the tolerances of 0*30' are instructive).
Assuming SAI is as stated on the "after" measurement, would that over 1 degree difference between the two be sufficient to hide a caster or frame problem?
Thank you thank you.
Why would coupe and sedan alignment be different? :dunno:
 

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Frankly I wouldn't worry too much about the "absolute" number of SAI as much as whether it is even side to side. This is what tells you if your chassis is "square". Your alignment readings actually look pretty darn good. Keep in mind that the set back is only, what, 20 minutes? That is a very small amount. If you have a bunch of setback you would typically find Caster problems. Think about the wheel hitting a curb straight on and shoving the wheel back in the fender causing set back and straightening up the caster angle in the process. Having an SAI problem you would expect to see Camber problems along with it. But typically that would be an SAI problem on one side as if you had hit a curb perpendicular to the wheel by sliding and steering away from the curb. Hope that makes sense.
Yes it does make sense. I had to read it a few times to get it to sink in :) It seems odd to see red and it not really be bad. But, I feel much better after hearing your explanation. The car has had a few suspension parts replaced, all BMW OEM, so when I saw the SAI, and then red your explantion eirler, I starting worrying about it again. I know the frame is not damaged and had it professionaly inspected (twice really) when the suspension parts were replaced.

While in the "green" I am disappointed that the tech did not adjust the front camber more towards target. Next time, which is coming soon with new tires, I'll insist.
 
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