Strut Mount Position re Alignment - Tutorial Please?

I do not understand how the positioning of the struts (front and rear) in the slotted holes affects the alignment. Can someone explain? Is relocation of the strut mounts in the slots considered part of the alignment process? For what purpose? I ask because I had my car aligned today at a tire store that seemed proficient. There were lots of small adjustments needed - no surprise, I bought the car a year ago and have no real service history on it - but in the end they were unable to achieve the correct camber on the right side of the car. My car is lowered on Techart springs and I expected it to have a lot of negative camber but the left side is in spec and the right side has more camber. The technician made a large adjustment in the position of the RF strut at the upper mount. He made NO adjustments to either side on the rear upper mounts. Wouldn't some movement of the rear upper mounts result in a change in the camber? All of the DIY spring replacement write-ups suggest you mark the location of the upper mounts so that you can put them back where they were when you reinstall. Why? Just to keep the original alignment in the ballpark or ? I am not unhappy with the alignment (yet) but trying to understand which adjustment affects which measurement.

Just had my alignment done by a Porsche race shop after lowering and they did not mess with the upper rear mounts, only the front. They were able to get -1.8 camber on each side just by adjusting the tops all the way. They wanted -3.5 so I've purchased adjustable camber mounts for the front which add 1.5 degrees more available camber which is close enough. Your other option is GT3 control arms which will allow you to get as much camber as you want and fix any caster issues while you are at it. FYI, I had a coupon for a local alignment place that discount tire gave me for $75. Instead, I used the race guy for $250. But they also got the preload off my drop links and checked for any other issues. At least for this initial setup, getting it done right was worth the extra. Plus, I picked his brain the entire time while his help did the alignment. That alone was probably worth it.

Here is the alignment sheet and I wonder why they couldn't get the right side camber to equal the left side - especially when no changes were made to the rear strut mounting....??? Perhaps the way the rear strut mounts to the suspension, it doesn't really have any effect at the rear?? (if so, wondering why we mark the original location when doing work on the struts)

That doesn't look right at all. How far did you lower it? Did you add anything else besides the springs?

It is just lowered on Techarts and Koni Sports. I don't want to start a critique of the results as much as I want to understand how adjustment/movement of the strut tops plays into the alignment results. Other than the right side camber, this all looks OK to me and is surely better than it was. The purpose in getting the alignment (other than having had all 4 struts out of the car) was to try to reduce what seemed to be extreme inside rear tire wear. Seems to me I am still going to have an issue with the RR in this regard.

OK, I found some info on line that says the front camber adjusts with the upper strut mount and I see that it was moved quite a bit on the PS so I think they made a best effort to reduce the RF camber though I don't understand why it could not be reduced to match the LF. I still haven't found anything on the rear struts but I am guessing that the camber is not adjusted by the top strut mount, though I still don't know what effect moving the rear upper strut mounts in their slots may have on the rear alignment.

So if you assume that the alignment shop is competent, front adjustable camber plates and rear adjustable upper control arms (dogbones, set of 4) will solve your problems. If you are interested, I have a set of used adjustable camber plates that I picked up on RL Classifieds but don't need now (just bought a used set of GT3 lower control arms which do the same thing). $300 shipped. http://www.rennline.com/Sealed-Front...oductinfo/S20/

Adjustment/movement of the strut top obviously changes the camber of the wheel. You have a before and after alignment diagram but that is just relative. The real question is - what are the correct specs for your lowered car w/Techarts and Koni Sports and how close are you to those specs? Of that I have no idea. Maybe someone knows.

How old are your springs? I'd figure out WHY the alignment is uneven. 1deg isn't a crazy amount, might just be too low that you can't compensate. Front suspension is McPherson strut. The hub is mounted to the lower control and toe arm below and to the shock up top. So the shock mount is part of the alignment geometry. In the rear it's a multi-link system. The hub is mounted to a similar control arm/ toe arm below and two "dog bones" up top. They control the geometry in this set up. Changing the angle of the rear shock will not affect alignment.

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Sorry, I just reread the thread and I don't think I answered any of your questions in my previous posts. Yes, the front camber is adjusted using the upper strut mount. The rear camber is adjusted using the eccentric camber adjustment on the control arm. It is the funny looking bolt that looks like it has a sundial on it. The rear upper strut mount is not used for alignment (as jj1 stated). Also, here is a good article that talks about the different things that can cause alignment challenges: http://www.pelicanparts.com/techarti...ur_Carrera.htm

Thanks all. I'm up to speed now I think. I compared the alignment specs between factory lowered setup (X74) and all the other configurations and the only difference is the camber which is a little more negative front and rear. The rear spec is 1 deg 40 min so I am close to that on the LR but not the RR. Slakker - thanks for the offer but I am going to dig deeper to learn why the camber is in range on one side and not the other before I start adding aftermarket parts.

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Has this car ever been in an accident before? That could be one explanation why they can't get the right adjusted correctly.

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Well, I don't think so and Carfax doesn't think so but that doesn't mean it hasn't. Would have to be a peculiar accident to affect camber alignment both front and rear on the right side of the car unless someone just slid full sideways into a curb.

Could also be worn out bushings.

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Not really rare as you might think. I've seen it a few times. More recently, one of the guys I know drove though a big pot hole on passenger side. Just bent both front and rear control arms enough to not be able to get alignment in spec. Otherwise visually it didn't look noticeably bent in anyway. This particular scenario is probably not likely though in your case since our control arms are cast and would most likely crack or break. Who installed the suspension? Did they line up everything correctly? (spring to the strut to the strut mounts)

I did the suspension install and if you mean the "compensating plates" and all the other little bits then yes I am sure that is all correct. I suppose worn bushings are a possibility at 70K miles but it doesn't drive like it has worn bushings and you would think if they were worn enough to create this issue that they would move around just doing the alignment and would be apparent to the tech doing the work. Just when I thought I was "done" working on this car for a while, now I'll have to get to the bottom of this one.

I'm guessing that it was the alignment tech. I just lowered mine to X74 spec with 80k on it and it aligned without issue. The only difference is I had adjustable rear toe links.

All good alignment place will not do an alignment if any of your bushings are worn. This is the first thing they check when they have it up on the rack as they've learned in the past that it will affect them from being able to align it perfectly.

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Maybe. But it looks to me like he used all of the available camber adjustment on the RR and still couldn't get there. Is there another way?

My first guess is worn, sagging springs. Were they bought used? Than consider a different alignment shop to verify the numbers are correct. Than I would triple check your install. Lots of pieces in these shock mounts. Cups, thrust bearings, rubber bushings... One flipped or missing or out of order piece could cause issue. But the first 2 are my best guess if you don't have recked bushings.

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+1 And I'm not just saying that because jj1 is who I get my suspension and tire advice from. OK, actually I am.

jj1 - sounds like you are suggesting that ride height or a ride height difference side to side is part of the problem and I don't have these issues (I don't think). I understand assembling the parts incorrectly would cause problems but unless they result in a ride height difference I don't see how that would be related to alignment.

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The good news is you now have all of the information in this thread you need. All of the most common issues have been listed for you to check out and eliminate one by one if you choose. Also listed is the hardware needed to correct it, once again if you so choose. Good luck and let us know how it turns out.

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^So let it be written, so let it be done...^

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I'm not trying to produce a proclamation from on high. Every thing that was suggested to him he argues with why that's probably not the case. At some point you have to move past theoretical discussion and pick a course of action. In this case it's either troubleshoot the cause by testing all possibilities and fix if able, purchase the hardware that will fix it regardless, or be happy with what you have.

I apologize for coming across like I am arguing. I thought I was providing feedback on the possibilities. I appreciate all of the input on this and will continue to try to figure it out with the suggestions provided.

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No worries, I was trying to point it out without coming across like an ***. Then I got called out for it and came across as a bigger ***. Lol. Less than a degree off isn't horrible as pointed out above so it may not matter or cause you any issues if you are only driving on the street. If you want to figure it out, either try a different alignment shop or go back and double check everything with the installation. Also, find some truly flat ground (easier said than done) and get out your measuring tape to check heights.

My concern about the difference side to side is sort of an academic thing I guess. I am more concerned that the 3 degrees of negative camber on the RR will cause accelerated inside tire wear, which I had before the alignment and was trying to cure

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Hopefully getting the toe down from .43 to .21 RR and evened out on both sides should lessen the wear. I'm running .25 toe and 2.5 camber in the rear so we will find out together how bad it wears. Also, FYI, my guy recommended flipping the tires as they start to wear, even on my Pilot Super Sports which have an "outside" side. I highly discourage going against manufacturer's recommendations on tire usage (legal disclaimer) but I am going to give it a try.