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Discussion Starter #1
Inner sides of my tires are worn out and my supposition is that is caused by wrong camber which is out of limits (see picture, left and right camber are -2°03' and -1°37'). Toe is adjusted in positive (as toe in), because of prevention of additional worn of inner side of tires.
I plan to buy "camber correction kit" and my question is: if correction with this kit isn't sufficient for correct adjustment of camber what are additional possibilities of this adjustment? Change of pillar with wheel hub or use of spacers in the support of upper wishbone?

946855
 

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A camber correction kit is not really of much value on 156, 147 & GT.
Someone developed one but it seems to affect castor adversely.

Normally when the camber goes to much negative it is because the front springs have sagged due to decreased ride height.

I guess your GT has the equivalent of 156 Sportpack/Veloce suspension. That being the case, if you carefully measure from the centre of the front wheels vertically up to the wheel arch, there should be 370mm gap. I guess yours is 350-355mm.
New front springs should correct that.
I'd count the coils of your front springs to be sure. I expect your car has later spec 8.8 coil front springs rather than 9.8 ones which, AFAIK should indicate standard suspension.

You may have to adjust the front subframe slightly closer to the right to reduce left side negative camber relative to the right side but the current difference will help steer it up the camber of UK roads.
 

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Discussion Starter #3 (Edited)
In my initial comment I don't emphasize that my GT isn't lowered by use of some non-standard springs, but after change of rear springs my impression is that distance between tyre and front arches are significantly smaller than corresponding rear distance. Maybe my front springs have lack of initial stiffness.
My old alignment report (from 2013) indicates to this fact when cambers were: left -1°30' and right -1°18'. Picture shows eLearn data of my springs...
Probably I can make right thing with combination of new front springs + camber correction kit... :)
Thanks for your advices and ideas!
946873
 

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Discussion Starter #4
Measured distance according to @Fruity suggestion: it is ≈360mm.
 

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Left side could be a little more worn if you drive alone a lot of times. So it can have more negative camber. You can use dremel and make oval holes on the strut body so that the aluminium carrier can be moved more out, 2mm on the left side should get you into 1 degree 40 minutes. But first check diagonally under the car some mounting points to be sure that the subframe is ok and in the right position. You can make oval just three holes and rotate it like i have done, will get less camber and a little more caster (as i see it is less on the left)
Mine is a little extreme because it is a racecar and has longer custom lower arms.

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Discussion Starter #6 (Edited)
Btw, I see yellow bush right... (y)
Thank you @alan Q4+33... I think it is very useful advice and good idea because three oval holes make possible (yellow) rotation around a pivot disc and two (red) translation - one in positive caster direction and one which makes camber more positive.
Important question: which moment of tightening of three screws in oval holes are sufficient to take vibrations and forces in driving? Is a solution to put some kind of wedge in remaining empty space of oval holes near to nuts?
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Yes like that, you can see i made an arrow on the metal and did exactly like you described.
You can put additional M8 screw in the hole near yellow arrow, with very wide washer.
I tightened the screws normal like before, no problem. But yes you can cut little piece of metal and put it in the oval opening to stop the movement.
The move that i made cca 5mm, changed the upper balljoint location 5mm more out and 3mm more back.
 

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Discussion Starter #8
If the length of a pillar is approx. 350mm then displacement of upper balljoint of 5mm makes change of angle near to 50'. Does additional correction of camber can be done by use of "camber adjusting kit" (see picture) and use of thin spacers between strut body and aluminium carrier?
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You may have to adjust the front subframe slightly closer to the right to reduce left side negative camber relative to the right side but the current difference will help steer it up the camber of UK roads.
The distance between the centres of the pivot balls in the lower and upper BJs is 360mm (as I have measured it on my 147, which involves some estimation of ball centre locations since the balls are hidden inside the joint).

A 360mm distance between BJs means that if either the upper or lower BJ is laterally repositioned by 1cm (relative to the other BJ), then the camber will change by 1° (not an absolutely exact correlation, but very close and easily near enough). So, for every 1mm change in the lateral position of one of the BJs (either the upper or the lower, but not both at once), there will be a corresponding 0.1° change in camber angle. This also works for caster angle, with a longitudinal change in BJ position.

In this case:
Left side camber is -2°03'. Expressed decimally this is -2.05° (we can call this -2°, it's so close).
Right side camber is -1°37'. Expressed decimally this is -1.62° (which I'd be happy to call -1.5°).
So 'cross camber' is 0.43° (the difference between left and right side cambers, which I'd be happy to call 0.5°).

So to equalise the front camber angles, on each side it needs to be changed by half of 0.43°, i.e. 0.215° (or at least a near enough approximation). To effect a 0.215° change in camber on both sides by means of moving the subframe, the frame would need to be moved sideways by 2.15mm (or thereabouts, we shouldn't get too anal about absolute precision here).

In this case the subframe needs to be moved about 2.15mm to the right, which will also move both lower BJs to the right by the same amount. This will decrease neg camber on the left side and equally increase it on the right.

It might or might not be possible to achieve this much subframe relocation, there is a good chance that there won't be enough clearance between the mounting bolts and the corresponding subframe bolt holes, or, the frame may already be positioned near to or at the maximum rightward position (...?).

There is more scope for camber equalisation to be had by 'slotting' the holes at the top of the 'strut' tower, as Alan has done with his racer. I've done a similar thing with my road car (only on one side just so that I can equalise the camber). I've done a similar thing on the other side, but with longitudinal hole slotting so that caster can be equalised.

The same 10 to 1 correlation applies as for subframe relocation, ie. for every 1mm of lateral upper BJ repositioning there will be a 0.1° change in camber, and so for every 10mm of BJ relocation there will be 1° of camber change (or at least very near to it).

Regards,
John.
 

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If the length of a pillar is approx. 350mm then displacement of upper balljoint of 5mm makes change of angle near to 50'.
Yes, I agree with what I think you probably mean, see my previous post.

However I don't agree with what you actually stated, and suspect that you may possibly be misunderstanding the degrees and minutes system of angle measurement (apologies if I have this wrong). In this system a 'degree' is split up into 60 equal divisions, i.e. 60 'minutes', so 50' (fifty minutes) isn't half a degree, but expressed decimally is 0.83 of a degree. Half a degree is equal to 30' (30 minutes).

Have a look at this angle convertor: Degrees,minutes,seconds to decimal degrees converter

Whether the distance between BJs is 350mm or 360mm makes little real difference, for all practical purposes it is still near enough with either length to assume a 10 to 1 correlation (mm to degrees) between BJ relocation and camber change. There is a difference, but it's not very significant.

Does additional correction of camber can be done by use of "camber adjusting kit" (see picture) and use of thin spacers between strut body and aluminium carrier?
No. Spacers fitted as you describe will move the inner end of the wishbone slightly downward, but have no significant affect on camber.

However, to be utterly anal about this, because moving only one end of a lever arm causes that end to move not in a straight line but in an arc, in theory there would some affect on the camber. But, it would be less than miniscule and of absolutely no consequence (my guess is that it probably wouldn't be detectable on most alignment machines).

Regards,
John.
 

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You can use dremel and make oval holes on the strut body so that the aluminium carrier can be moved more out, .................. You can make oval just three holes and rotate it like i have done, will get less camber and a little more caster (as i see it is less on the left)
As above I have done a similar thing with my car. With one of the towers I've made lateral 'slots' for camber equalisation, and the other tower with longitudinal slots for caster equalisation.

At the 'camber tower' I slotted all four stud holes so that only camber can be affected (i.e. camber changes as a by-product of the KPI being changed). At the 'caster tower' only caster can be adjusted.

The holes have been slotted by about 10mm, more than enough to equalise the camber and the caster anges if that is the only goal. If the intention is a substantial change in camber on both sides, then 10mm slots will get only about 1° camber change.

I used larger thick washers under the nuts, to spread the clamping load over a larger area 'under' the nuts.

The smaller aluminium 'lug' with the small threaded hole, I ground that away completely (it serves no purpose I can divine, other than to positiuon the aluminium casting, which is what I wanted to change...).

Rather than relieving / cutting away (mutilating...?) the large hole in the tower, I just removed the three intruding 'tabs' around the hole ID, and also created a shallow slot in the side of the aluminium 'dome' so that the tower top can 'insert' into the slot at the extreme of possible adjustment.

With my particular car (YMMV, i.e. it will), to achieve equalised front camber (with a mass = to driver weight in the seat) I needed to deduct of 0.5° of neg' camber on the right side, so had to move the upper BJ (and aluminium casting) outward by 5mm. To achieve equalised caster, I had to move the left side upper BJ (and aluminium casting) rearward by 5mm (adding 0.5° to the left side caster angle).

Regards,
John.
 

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Discussion Starter #12
First of all, thank you @johnlear for your detailed explanation of procedure and goodwill to help me... (y)
I understand that you suggest two phase:
a) equalisation of cambers and
b) correction of both of cambers separately in proper limits (between -0°59' and -0°19', i.e. -0°39' in "ideal" case, according to GT factory data).

Could you, please, make some photos of "camber tower" and "caster tower" configuration of slots.

Btw, my calculation of relation between relative lateral displacement of BJs and camber angle is correct:
5/350=0.01429 and arctan(0.01429)=0.818°, i.e. 49.1' ≈ 50'.
Additionally, in your case... arctan(10/360)=1.591°, i.e. 1°35'.

Regards - Dusan
 

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Discussion Starter #13
No. Spacers fitted as you describe will move the inner end of the wishbone slightly downward, but have no significant affect on camber.
 

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I think the video is wrong. I have little to no confidence in the accuracy of the alignment procedure as depicted in the video, somebody is doing something wrongly, or, there is an issue with the suspension that is creating unstable alignment settings.

(Note that the video includes photographs in which extreme negative camber is confidently mis-labelled as positive camber - and vice versa - which does not inspire any confidence whatsoever in the data presented...)

There is no way that adding those spacers can have lessened right side camber from decimal -2.6° (-2°36') to only -0.42° (-0°25'). That is a huge angle change of 2.18° (2°10'), just from a slight change in the angle of the upper wishbone.

Please keep in mind that a camber change of 2° that is achieved by laterally moving either the upper or lower ball joint requires that the BJ be moved inward or outward by a whole 20mm...

If the exact same modification were done on both sides (i.e. same thickness washers inserted, as shown in the vid), then we should expect to see a very similar reduction in negative camber at both front wheels, i.e near enough to a 2° decrease in negative camber (as occured with the right side wheel). This is not even close to what apparently occurred, according to the numbers as presented...

The left wheel starts with an initial camber (as measured) of +0.07° (+0°04'). After the washers have been added, the left wheel camber becomes -0.47° (-0°28'), which is actually an increase in negative camber, not a decrease as we should expect to occur and as it is said to have done at the right side wheel...

With the same 'washer modification' performed on both sides of the car, the left side camber changes by only 0.54° (i.e. +0.7° added to -0.47°), compared to the right side camber changing by a much greater 2.18°. If the left and right side camber changes are both a direct result of the identical washer insertions, then the changes in angle should be much more similar on both sides (since it is the product of the same 'adjustment'), but the angle changes are very disimilar...

Something is obviously wrong with the measurements, or the car.

Regards,
John.
 

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Btw, my calculation of relation between relative lateral displacement of BJs and camber angle is correct:
5/350=0.01429 and arctan(0.01429)=0.818°, i.e. 49.1' ≈ 50'.
Additionally, in your case... arctan(10/360)=1.591°, i.e. 1°35'.
Hi dusan,
I don't do trigonometry, just not smart enough. I Iet CorelDraw do my calculations for me in the form of diagrams, so according to CDraw:

If the distance between the upper and lower ball joint centres is estimated to be 350mm (difficult to measure with precision on the car), then laterally moving either the upper or lower BJ will change the KPI angle by 1.6°. The camber will therefore also change by 1.6° because whilst KPI and camber are not the same angle they are unalterably interlocked (with most suspension designs, but not all).

So the conversion ratio for lateral ball joint relocation is 1mm for every 0.16° of KPI / camber change. I did the original calculation (drawing) so long ago that I had forgotten that for ease of use while performing an alignment I approximate the ratio to 10 / 1, which I find is good enough for all practical purposes. In reality I have found that the 10 / 1 ratio works well enough, and that moving the upper wishbone by 10mm does indeed result in a camber change that is very close to 1°.

If we assume that the distance between BJ centres isn't 350mm but rather is 360mm (as per my own partially estimated measurement), then the ratio of BJ relocation to KPI and camber change is of course affected, but by less than 0.1° for every 10mm of BJ relocation, so of little practical significance.

Regards,
John.
 

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Discussion Starter #16
The left wheel starts with an initial camber (as measured) of +0.07° (+0°04'). After the washers have been added, the left wheel camber becomes -0.47° (-0°28'), which is actually an increase in negative camber, not a decrease as we should expect to occur and as it is said to have done at the right side wheel...
It is one thing which is unclear for me too and I asked author of clip for explanation...
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Camber is not adjustable in stock form of the car. Camber goes negative slightly when lowering the car. You either have worn suspension components or accident damage on the car. If it is accident damage you are chasing ghosts by trying to correct it. IMO
 

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I understand that you suggest two phase:
a) equalisation of cambers and
b) correction of both of cambers separately in proper limits (between -0°59' and -0°19', i.e. -0°39' in "ideal" case, according to GT factory data).
I have a suspicion that most modern car tyres are purposely designed to be relatively camber insensitive, and that this is possibly one reason why car manufacturers can get away with no longer providing a means of camber adjustment as once they did. The other reason would be that modern unibodies are more accurately built (by laser guided robots) than they once were, so camber is more equal at assembly without needing to tweak it.

I aim to get my cambers equal to about 0.1° or so, but less than 0.5° is probably OK with most tyres and most cars.

Could you, please, make some photos of "camber tower" and "caster tower" configuration of slots.
I don't really want to take and post photos, because I'm lazy...

My modifications look very similar to those in the photos already posted by Alan. But there are some differences.

With both towers:
All four of the stud holes have been slotted, not just some of them. The casting (to which the upper wishbone is attached) can only move laterally in the slotted holes, not swing in an arc.

I've used large washers under the nuts, to spread the clamping load into a larger area of the tower metal. This is because removing metal to make the slots decreases the area of metal that otherwise would be clamped by the nut.

I have not slotted the smaller of the two large tower holes as Alan has done. Instead I have removed the aluminium 'lug' that protrudes into this hole, so that the lug can not restrict adjustment. (I ground these lugs off with an angle grinder, lube the wheel with beeswax to stop the aluminium clogging the grit...).

And with the tower modified to make camber adjustable:
I cut small slots into the side of the aluminium 'dome' it, so that the three 'tabs' (which are spaced around and impinge into the 'dome hole') can insert into the slot as the casting is moved toward the extreme of adjustable camber range. If these slots did not exist then the tabs would prevent the aluminium casting from being moved inward or outward. It would be as effective to grind or cut the tabs away.

The same thing with the tower modified for caster adjustment, except that the slots have been cut to permit the casting to be moved fore and aft (instead of sideways).

Regards,
John.
 

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Discussion Starter #19
you are chasing ghosts by trying to correct it.
Any development needs some kind of "chasing of ghosts". :)

I don't really want to take and post photos, because I'm lazy...
Dear John, it is OK, because your explanations are really sufficient in technical manner.
In that sense, many thanks for additional very useful comments! (y)
 

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Discussion Starter #20
Measured distance between upper and lower ball joint of wishbones on 147/156/GT front wheels is ≈450mm. In that sense, it is needed additional relative lateral displacement between ball joints of ≈8mm (exact is 7.85mm) for change of camber of .

By use of washers under two holes of strut body (see video clip from YT), it is needed washer of 3mm for achievement of lateral displacement of upper ball joint of 7.5mm what is enough for change of camber of ≈57'. That is consequence of ratio between height of aluminium cast (150mm) and distance of holes with and without inserted washers (60mm), therefore "factor of enlargement of displacement" is 150/60=2.5.
But, probably... it is only theory. Better approach is method with slotted holes, described by John and Alan.
 
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