HELP! Lowered with alignment problem




Do you have the final spec sheet and would you be willing to share it with us? TKS
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Also, many thanks to roadtalontsi for talking us through this issue (and lots of other ones),very much appreciated.
the first had camber out of spec by ~0.1 deg
the second brought it within spec, changed about 0.3 deg but still over the mid point of 2 deg, but it pulled caster out of spec
I doubt I could feel these differences
what is interesting is the lowering amounts/ride heights
do you have a pre- lowering spring alignment sheet?
front spec is ~ -8 mm or so (mine avg -13.5 and within spec of ~-15 to 0)
rear ~ 0 mm (mine avg -3 and within spec of ~ +3 to -8)
(the mm is estimated since spec is given in degrees and it's not linear)
mine's a 2009 and the specs for your car are different, eg, my front camber ~1.5 and yours is 2, rear, mine 1.5 and yours 2.3
yours
F -26 mm avg
R -20 mm avg
using my stock for a baseline lowering =
F ~ -13 - (-26) ~ 13 mm of drop
R ~ -3 - (-20) ~ 17 mm of drop
it looks like the H&R may drop the front a bit more?
Eibachs did this intentionally on some applications to shift weight rearward
It would be interesting to have the numbers for the same car with the same fuel load
the first had camber out of spec by ~0.1 deg
the second brought it within spec, changed about 0.3 deg but still over the mid point of 2 deg, but it pulled caster out of spec
I doubt I could feel these differences
what is interesting is the lowering amounts/ride heights
do you have a pre- lowering spring alignment sheet?
front spec is ~ -8 mm or so (mine avg -13.5 and within spec of ~-15 to 0)
rear ~ 0 mm (mine avg -3 and within spec of ~ +3 to -8)
(the mm is estimated since spec is given in degrees and it's not linear)
mine's a 2009 and the specs for your car are different, eg, my front camber ~1.5 and yours is 2, rear, mine 1.5 and yours 2.3
yours
F -26 mm avg
R -20 mm avg
using my stock for a baseline lowering =
F ~ -13 - (-26) ~ 13 mm of drop
R ~ -3 - (-20) ~ 17 mm of drop
it looks like the H&R may drop the front a bit more?
Eibachs did this intentionally on some applications to shift weight rearward
It would be interesting to have the numbers for the same car with the same fuel load
the first had camber out of spec by ~0.1 deg
the second brought it within spec, changed about 0.3 deg but still over the mid point of 2 deg, but it pulled caster out of spec
I doubt I could feel these differences
what is interesting is the lowering amounts/ride heights
do you have a pre- lowering spring alignment sheet?
front spec is ~ -8 mm or so (mine avg -13.5 and within spec of ~-15 to 0)
rear ~ 0 mm (mine avg -3 and within spec of ~ +3 to -8)
(the mm is estimated since spec is given in degrees and it's not linear)
mine's a 2009 and the specs for your car are different, eg, my front camber ~1.5 and yours is 2, rear, mine 1.5 and yours 2.3
yours
F -26 mm avg
R -20 mm avg
using my stock for a baseline lowering =
F ~ -13 - (-26) ~ 13 mm of drop
R ~ -3 - (-20) ~ 17 mm of drop
it looks like the H&R may drop the front a bit more?
Eibachs did this intentionally on some applications to shift weight rearward
It would be interesting to have the numbers for the same car with the same fuel load
Also the mm calculation is based on the angle of the front lower control arm and rear axle using a special tool - romess gauge. So if your using a tape measure or any other way your results will vary quite a bit. I'll be doing an alignment laster this week probably on my 10' sedan with kw's - not lowered very much and ill post up the spec sheets
Also the mm calculation is based on the angle of the front lower control arm and rear axle using a special tool - romess gauge. So if your using a tape measure or any other way your results will vary quite a bit. I'll be doing an alignment laster this week probably on my 10' sedan with kw's - not lowered very much and ill post up the spec sheets
change in the front:
L from 2 deg 30' to 2 deg 17' = 13' ~ 0.216 deg
R from 2 deg 33' to 2 deg 13' = 20' ~ 0.333 deg
I used the avg of ~ 0.3 deg or 18', very close
avg is 0.275 +/- so in fact not 0.5 deg or 30', it is actually LESS than my estimate of 0.3 deg, NOT 0.5 deg
loading (ie passengers) will change it more than that
the rear did not change (within the error of repeatability) and is within spec and on the 'flat' side
They did not adjust caster to counter road crown, it was a consequence of the camber adjustment. The cross caster is a deg off and both sides are out of spec where as they were in spec and essentially equal before. (does it even have caster adjustment? most BMW's don't)
I would not have done the bolts for such a minute (pun intended) change. I would have observed tire wear patterns and tried to equalize/mimimize it with toe compensation (perhaps a bit on the 'straight' side of spec). But either way those differences are moot and imho opinion would not be felt.
As far as the ride height spec, it is sensitive but should be repeatable (fuel load, etc.), My estimates were based of fitting his numbers and mine to a geometric arc equation. That is why I wish he had pre-spring numbers it would be interesting to see the relative drop.
I learned to do my own alignment, no pro by a long shot but understand the procedure and goal. My e46 required weighting: 68 kg each front seat, 68 kg center rear and 21 kg trunk with full tank of fuel. BMW does measure rife ht with a ruler, floor to lip. pg 31.
the following doc has some good info (although it states the M3 does not need weighted when you pull up the software it says it does?)
http://www.google.com/url?sa=t&rct=j...4dHPOZhxQePmnA
Last edited by Ingenieur; Dec 2, 2013 at 05:46 PM.
as for the .3 degree etc... ya you got me there, I didnt feel like looking at the specs again all sideways like. non of the benz's require weight either when doing the alignments. Only the sls needs weight when tightening control arm bolts.
5 deg = 11.4% and 10 deg = 17% slop
6% slope = 3.4 deg
if a road 5 or 10 degrees there is a road design issue and this is dangerous
water will flow well on a rough surface at 3% or so (sewer lines range from 1 to 2% for reference)
say you have a 24' wide road (2 lanes same direction) at the max 6%
crown rise/ht = sin (arctan 0.06) x 24' x 12"/ft = 17"
from the edge to the center the road would rise 17", not too steep
if 10 deg = 24 x 12 x sin(10) = 50" of rise, no way... >4'?
50/(24 x 12) x 100 = 17% slope, way more than needed
not trying to argue, just to make the point his first alignment was good
Last edited by Ingenieur; Dec 3, 2013 at 05:41 PM.




it appeared they did camber bolts to reduce it ~0.3 deg??
The factory suspension has no front camber/caster adjustment and the rear has no camber adjustment. You need camber/caster bolts (AKA crash bolts in the front). For the rear you need upper rear adjustable control arms. Any good alignment shop will have the front crash bolts. Call ACG in San Diego for the rear control arms.
since this got bumped i just noticed this reply. When you pull the camber bolts in you lose caster. So if all they did was pull in left and right cambers you wouldn't be causing a caster pull, both casters would have dropped pretty much equally. Just pulling in the left camber alone would only give it around .20-.30 change in caster. Yes i realize the caster didnt change on the right side and sometimes you see weird stuff like this. In a perfect world where you and all your engineering numbers work all the time unicorns poop rainbows and global warming means it shouldnt be 15* in texas but it was last weekend (shut the whole state down - really sad). My thoughts are it's something to do with the weight of the vehicle shifting or the way the alignment machine gets it's readings does this sometimes. Im not disagreeing with the original alignment being good. sure it is very neutral, in a perfect world this is what you want. Im not trying to challenge you or your engineering degree. I have no doubt you are smarter and more knowledgeable than me. The difference is I personally do alignments almost daily. I wish for the life of me i knew why the 221 s-class's need over 2* of pull sometimes even more to get them to drive straight it makes no sense. The s-class is a mystical beast. You calibrate the ride height and it changes to whatever it feels like. say you pull the left camber in, let the suspension raise and lower (airmatic car) do the sweep. for some reason the left camber stays the same and now the right camber just went more negative? Theres alot i cant explain and im not going to sit here and lie to you about it, what i can tell you is i can make a car drive the way it's supposed to. Like i said im not trying to have a pissing match. I just wanted to help this guy out and try to explain why and how it was done.
again
why wouldn't they adjust castor to the middle of spec, then dial in a bit of offset on one side to compensate for road crown if that was the whole point of the excercise? but they left both sides out of spec...because these bolts are meant to adjust for a distorted geometry due to a collision...
taking into consideration that now he has a 'clunk' in the front end and the accuracy of his original alignment I would not have touched anything
hindsight is 20:20 but in this case rings true
for all we know the 'pull' could have been due to tire pressure delta or a fat chick



