Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: terry paget on 13 June 2015, 17:50:17
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I thank Nick W for advice in this matter. I have now devised a technique whereby I can reset camber and toe in precisely and rapidly. This forum may not approve as some senior members dislike my supporting the front of the car under the wishbones. Recalling my schoolboy mathematics - the cosine rule - I calculate that 10cms extension or compression of the Mcpherson strut spring will increase camber by about 3 degrees. Therefore the setting of -1 degree 40 minutes when normally loaded, wishbone horizontal, is a compromise allowing for this. You see from pics I have set both front wheels at minus1.6 degrees. The tool I have used is the Budget Digital Angle Gauge with backlight, cost £20.50, works a treat. Pics also show how I support the car, and how I set the toe in by adjusting front wheels parallel to rear with steering wheel centred. I invite comments.
[url]https://www.dropbox.com/s/4efchsl265jjkff/camberNS.jpg?dl=0]https://www.dropbox.com/s/mb3wdyeukh6mspz/wbonesupport.jpg?dl=0[url]
[url]https://www.dropbox.com/s/4efchsl265jjkff/camberNS.jpg?dl=0 (https://www.dropbox.com/s/mb3wdyeukh6mspz/wbonesupport.jpg?dl=0[url)
https://www.dropbox.com/s/7ct2y7r4578kovc/camberOS.jpg?dl=0 (https://www.dropbox.com/s/7ct2y7r4578kovc/camberOS.jpg?dl=0)
https://www.dropbox.com/s/nd9y02njilkua2w/tracking.jpg?dl=0 (https://www.dropbox.com/s/nd9y02njilkua2w/tracking.jpg?dl=0)
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Apologies, made pic error. Here is the nearside camber setting.
[urlhttps://www.dropbox.com/s/davvhxz9yyucwvz/NScamber.50%25.jpg?dl=0][/url]
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https://www.dropbox.com/s/davvhxz9yyucwvz/NScamber.50%25.jpg?dl=0 (https://www.dropbox.com/s/davvhxz9yyucwvz/NScamber.50%25.jpg?dl=0)
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How does the camber setting read when the car is on its wheels? I found it's just about possible to adjust it without removing the wheel or even jacking up the car. This was working in the street. Does need another person to help.
You need to check it again when you've adjusted the toe setting too.
I hope you are zeroing the gauge on the ground between the wheels. That needs to be done on a reasonably long straight edge, like a spirit-level.
Are you measuring anything at the rear suspension, or just hoping it's good enough? Adjusting the front on its own is fine on a simpler suspension system but can lead you astray on a sophisticated one.
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Thanks for the feedback Nick. For years I have been setting toe in with the front of the car supported under the wishbones, which works very well, always bang on first time. I believe I have now found a way of checking camber at the same time. Henceforth I shall do the camber first (wheels off), then the toe in with wheels on.
I found it quite difficult to adjust the camber. It is a 14 year old car and I presume it has not been adjusted before. Original settings were -0.5 left, -0.2 right. Bearing in mind the wide variation inherent in a McPherson strut/wishbone system I don't think it matters that much, but now I can set it I can see how tyre wear varies with camber setting.
The garage floor is horizontal, and I zeroed the gauge on a convenient steel vertical surface, part of the door frame, as checked with a spirit level.
I assume the rear is OK.
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https://www.dropbox.com/s/davvhxz9yyucwvz/NScamber.50%25.jpg?dl=0 (https://www.dropbox.com/s/davvhxz9yyucwvz/NScamber.50%25.jpg?dl=0)
I don't want to sound negative towards valiant attempts, but inevitably there are some major issues anyone reading should be aware of evident in this pic.
As Terry knows placing the entire wait if the car on the wishbone gives;
1 a good chance of bending the wishbone.
2 Risks damaging the rearward bush as the jacking point raises the wishbone up towards the subframe as you can see, this stretches the rubber up from the outer edge of the wishbone while the centre stays fixed.
3 the jacking point is inboard of the actual load bearing point of the wheel, so due to massive leverage of the normal load point being refused means the car is being set up to the incorrect ride height. This means when the wheel is refitted and the car lowered to the ground, the camber will be excessive.
4 as the gauge used is a level device, a couple of axle stands on blocks of wood doesn't mean the car is level relative to the gauge.
I'd strongly suggest taking a measurement from wheel rim to shock body as a guide, after the car has been set up correctly. Then use that measurement for future use. Your then working from known start point.
Having said that, the fact you have a pit means adjusting the camber with the wheels loaded / car on the floor "should" be fairly easy. A bit of tension on the shock bolts to avoid slop, but still allowing you to thump the wheel over at the top to achieve the correct desired camber should work as said.
Never jack on the dif. Never Jack on the wishbone. Dito stands.
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In all honesty these methods are not recomended as a final position. However highly recomended after suspension rebuild to try and get somewhere near the correct position until full set up is achieved professionally.
New suspension can take a few weeks to settle to its new ride height. So set up can be off if done too early anyway.
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That's also ignoring the fact that the desired camber setting is actually -1.10
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Thanks for your observations Chris. I am striving all the while to find a way of setting up the car. My experience of garages and tyre shops is abysmal. For decades I have had cars 'set up', and all they do is adjust the toe-in, usually on one track rod, leaving the steering wheel not central on straight ahead running. Members still report suffering this. My method on tracking certainly does better than that.
I was always aware of risk of bending wishbones, but never have yet so think that can be disregarded. they are more at risk of bending when I fit them and I use a long lever in the hole to pull them down to insert the ball joint pin.
I appreciate I should support the wishbone directly beneath the hub to apply the correct leverage to the wishbone; it's difficult to do. Perhaps Sassenach was right when he said I should dispense with the wood block.
I depend upon the garage floor being level, and the axle stands and wood blocks being matched in height, both reasonable assumptions, another reason for dispensing with the wood blocks.
The pit was no help in setting camber, and little help setting tracking. I'm always afraid of falling into it, so in this job it's a mixed blessing.
I don't believe camber affects the handling at all, but does affect tyre wear. I hope to find a setting that helps. Common sense suggests the wheel should be vertical in normal load straight running, yet Haynes states 1.6 degrees negative camber. I imagine this is to allow for the fact that this will go positive on suspension movement. At lest now I am able to experiment with different settings. In the past I have had Omegas where one front tyre wore evenly and the other wore badly on the inside edge.
It is easy for wheel alignment shops to measure all geometry parameters, more difficult to adjust them. Garages send customers' cars out to 4 wheel alignment specialists and they come back with impressive printouts of figures customers do not understand and mean nothing; waste of money.
Thanks for the feedback, it's much appreciated. This forum has a wealth of experience that makes running these old cars a pleasure.
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Haynes isn't called the book of lies on here for nothing Terry. ;)
Camber is used to counteract cornering wear. If set to 0 camber, by the time the tyre is worn to zero tread the outside edges will wear more due to cornering. So a good set up guy (not the retards in tyre bays that state " needs tracking mate" to every wear issue) will see that wear and adjust the camber accordingly. A more exuberant driver will need MORE camber to counter the wear caused by faster cornering.
This is why standard suspension is set to -1.10 and sport suspension set to -1.15, as sport suspension presumes more exuberant cornering.
At NO point was 1.6 EVER considered anything other than disasterous.
Further, consider the accuracy needed to measure 0,05 minutes (not degrees) of camber, and consider the methods explained here. Such as;
The assumption the garage floor is level
The thickness of the wooden blocks
The height of the stands
The angle of the wishbone and the contact point along that angle
The failure to consider ride height at any point
The accuracy of that gauge, known to be dubious alone even without the other variables above
The fact the target set up figure us incorrect and unaware of minutes or degrees.
....and I'm sorry to say Tell, that this is fishing in the wind, especially if your looking for a final position. You'd be better with Dtm's method of adjusting the nub to max camber then "knock it back a bit"
But why are you not IN the pit, loosening the camber bolts wheels on car on the floor and adjusting camber that way, via the gauge? You'd be FAR better that way as it removes all the variables except the gauge itself. That's how the set up boys do it, albeit with a floating pad under the wheel, so you'll need to roll the car back and forth between each adjustment to take out the pinch on the wheels track.
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Following this with interest as I expect to be changing shocks on the TD Estate in the near future. Regarding setting the camber with the correct ride height, I was told by a geo shop that setup should have simulated pax weight loaded into both front seats to achieve this. :-\
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Following this with interest as I expect to be changing shocks on the TD Estate in the near future. Regarding setting the camber with the correct ride height, I was told by a geo shop that setup should have simulated pax weight loaded into both front seats to achieve this. :-\
As yours has been set up previously, I believe? Follow the replicating camber settings in the guide. Involves remembering to measure the wheel rim to shock body gap before dismantling.
http://www.omegaowners.com/forum/index.php?topic=90652.0
Socket method is far more accurate than anything here.
Re weighting the car, Wim don't bother on this model. -1.10 is an unloaded figure.
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Yes I shall be following your guide Chris, sounds a sensible way to check/set, and can be very simply rechecked after running for a while. :y
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Re weighting the car, Wim don't bother on this model. -1.10 is an unloaded figure.
They used too, they weighted the drivers side on my first two visits to them (many years ago), they also asked what weight is usually carried in the boot of the vehicle.
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...but.... For others reading....as camber affects toe if camber is moved, it's by no means a replacement for full geo. the errors are too fine to be measured diy. It can only really be used to minimise wear while the suspension re settles, before full geo set up.
Apologies if that's an overly obvious statement to most here. :)
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Re weighting the car, Wim don't bother on this model. -1.10 is an unloaded figure.
They used too, they weighted the drivers side on my first two visits to them (many years ago), they also asked what weight is usually carried in the boot of the vehicle.
Interesting. I remember discussions on it here a while back, but they never approached the subject on any of my visits, I asked Tony directly once, just shook his head.
But as I have poly I didn't really worry too much. If oe bushes, I would of asked specifically to have it weighted and the wishbone bolts re tightened.
They had issues with centring the steering wheel, which later turned out to be rear track rods, and I asked if me sitting in the car would help when it was set up, and the answer was no. But that's a different question to ride height.
Don't know why they don't. Or the thinking behind not doing so, I should say.
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Not getting involved in the debate as I don't have the first clue about set up by diy. . . .
However isn't the most cost effective way to take your car to a shop that has the laser alignment and simply give them the settings from WIM?
Or a trip to WIM obviously being the best scenario?
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Not getting involved in the debate as I don't have the first clue about set up by diy. . . .
However isn't the most cost effective way to take your car to a shop that has the laser alignment and simply give them the settings from WIM?
Or a trip to WIM obviously being the best scenario?
Yes, but courtesy to Wim is a bit awkward sadly. Ultimately the correct settings do need inputting via a hunter hawk eye rig. With an operator prepared to go the extra mile to be within tolerance.
The issue here with a company that doesn't know the omega is the book settings are not good enough. It does NEED the wim setting/-1.10 camber etc.
So direct answer, yes Webby. Correct :y
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Not getting involved in the debate as I don't have the first clue about set up by diy. . . .
However isn't the most cost effective way to take your car to a shop that has the laser alignment and simply give them the settings from WIM?
Or a trip to WIM obviously being the best scenario?
Option 2 without a shadow of a doubt! ;)
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Not getting involved in the debate as I don't have the first clue about set up by diy. . . .
However isn't the most cost effective way to take your car to a shop that has the laser alignment and simply give them the settings from WIM?
Or a trip to WIM obviously being the best scenario?
Yes, but courtesy to Wim is a bit awkward sadly. Ultimately the correct settings do need inputting via a hunter hawk eye rig. With an operator prepared to go the extra mile to be within tolerance.
The issue here with a company that doesn't know the omega is the book settings are not good enough. It does NEED the wim setting/-1.10 camber etc.
So direct answer, yes Webby. Correct :y
That's the thing isn't it. If using ANother shop you need to really be watching them do it and trust they are following your advice.
Making it easy for them to do is also helpful (ie making sure you have new rear track rods so they're easy to turn etc.) otherwise you could just get a 'that will do' scenario.
Scott's tyres in northampton will do it (obviously local to me) but the guy there knows his onions and wasn't surprised when I asked gave him WIM settings.
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Not getting involved in the debate as I don't have the first clue about set up by diy. . . .
However isn't the most cost effective way to take your car to a shop that has the laser alignment and simply give them the settings from WIM?
Or a trip to WIM obviously being the best scenario?
Yes, but courtesy to Wim is a bit awkward sadly. Ultimately the correct settings do need inputting via a hunter hawk eye rig. With an operator prepared to go the extra mile to be within tolerance.
The issue here with a company that doesn't know the omega is the book settings are not good enough. It does NEED the wim setting/-1.10 camber etc.
So direct answer, yes Webby. Correct :y
That's the thing isn't it. If using ANother shop you need to really be watching them do it and trust they are following your advice.
Making it easy for them to do is also helpful (ie making sure you have new rear track rods so they're easy to turn etc.) otherwise you could just get a 'that will do' scenario.
Scott's tyres in northampton will do it (obviously local to me) but the guy there knows his onions and wasn't surprised when I asked gave him WIM settings.
That's a lot of the battle, having an open minded operator is key. They sound worth a go, from what you said.
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...assuming you can get the old boy to do it and no one of the lads ::) ;D
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Not getting involved in the debate as I don't have the first clue about set up by diy. . . .
However isn't the most cost effective way to take your car to a shop that has the laser alignment and simply give them the settings from WIM?
Or a trip to WIM obviously being the best scenario?
Just to be clear, it needs somewhere with the gear to do a full geometry check (ie, Hunter Hawk HD or similar), which is completely different and far more capable than what most places call "laser alignment", which is little more than dangling some mirrors and measuring bars off the wheels, and can at best get the front toe correct on the assumption the rear toe is perfect.
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Scott's have the full set up measuring all the angles. No idea of the name. But it was similar to the one we had at college.
Bloody expensive tho
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Not allowing you in the car up on the table is a liability issue rather than a geometrical one ;)
They tread a fine line allowing people in to watch tbh :-\
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When setting front camber with new springs do you set the machine up for 2 x 70kg weights then actually put the weights in or do as per old springs and leave them out of the car?
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More important to let the suspension settle for a week or three IMO. But that means getting the figures in the ball park diy on install. Which isn't for everyone.
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Everything on the front is being replaced so there won't be any datum points to work from off the old suspension. Car also gets used everyday so it's a one shot exercise with a review of tyre wear in a few months (does about 6K a year)
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Everything on the front is being replaced so there won't be any datum points to work from off the old suspension. Car also gets used everyday so it's a one shot exercise with a review of tyre wear in a few months (does about 6K a year)
Take the measurements from your old stuff before taking it off, then the wear should be similar to now
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Everything on the front is being replaced so there won't be any datum points to work from off the old suspension. Car also gets used everyday so it's a one shot exercise with a review of tyre wear in a few months (does about 6K a year)
Take the measurements from your old stuff before taking it off, then the wear should be similar to now
...as the guide on setting camber from the previous pre dismantled setting. :y
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Hi Anthony. I reset the camber on X168 , your old car, yesterday, to -1.1 degrees both sides, from -0.7 left and +0.3 right. It sounds like you are having a suspension shop replace all your front suspension components, and they have an optical alignment machine needing set up data. Advice here is camber setting of -1.1 degrees. I set my camber to -1.1 degrees front seats empty, then had the wife clamber into the car, reading did not change; so setting is not very load sensitive.
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I've got accelerated tyre wear on the inner edge both sides, hence the replacement. It's getting MV6 replacement springs from Germany (NOS) so I'm going -1.15 with toe at + 0.05 +/- 05'. If it's not so weight dependent I might tell the shop to calibrate with 70kgs either side, then leave the weights out allowing for future sag as it ages and settles.
Terry, that's interesting as it looks like it had shifted from where I had it set (-1.10) by the local WIM agent.
Rear has also been lowered with NOS MV6 so for thrust angle and camber, is rear toe best set at 0.00 ?
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Rear toe and camber both set by one adjustment, so they are always a compromise... usually 1°0.35' camber and 0°005/6 toe in. Critical rear measurement is that the thrust angle is 0° regardless of what the other measurements are :y
Front toe I always get set to 0°, although my car has poly vertical bushes too...
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Rear toe and camber both set by one adjustment, so they are always a compromise... usually 1°0.35' camber and 0°005/6 toe in. Critical rear measurement is that the thrust angle is 0° regardless of what the other measurements are :y
Front toe I always get set to 0°, although my car has poly vertical bushes too...
Thanks
Take that's a -1.35 camber
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Rear toe and camber both set by one adjustment, so they are always a compromise... usually 1°0.35' camber and 0°005/6 toe in. Critical rear measurement is that the thrust angle is 0° regardless of what the other measurements are :y
Front toe I always get set to 0°, although my car has poly vertical bushes too...
Interesting. For any particular reason Al?
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Rear toe and camber both set by one adjustment, so they are always a compromise... usually 1°0.35' camber and 0°005/6 toe in. Critical rear measurement is that the thrust angle is 0° regardless of what the other measurements are :y
Front toe I always get set to 0°, although my car has poly vertical bushes too...
Interesting. For any particular reason Al?
A few of us have tried them, for a combination of reduce maintenance and better handling, with varying degrees of success.
Mine handled fantastically when first installed, but destroyed themselves within days, so I went back to GM.
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Thanks. I've often wondered why we don't. :y
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Rear toe and camber both set by one adjustment, so they are always a compromise... usually 1°0.35' camber and 0°005/6 toe in. Critical rear measurement is that the thrust angle is 0° regardless of what the other measurements are :y
Front toe I always get set to 0°, although my car has poly vertical bushes too...
Interesting. For any particular reason Al?
If the fronts can be made to last the life of the car, then why shouldn't the rears?
Those with less success were basically using milled lumps of almost solid poly, which generally causes the welds and/or wishbone to fail, and gave a bone shaking ride.
My solution isn't perfect, taking alot of trial and error, not to mention tyre wear, to reach... but a little low speed vagueness/stiffness is a very small price to pay for missile precision when pressing on.
There is an underlying concern regarding wishbone fatigue, which is why they're generally not recommended, but this is looking to be unfounded as my bushes are four layers rather than a single lump, thereby allowing some (limited) slip :y
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I've got accelerated tyre wear on the inner edge both sides, hence the replacement. It's getting MV6 replacement springs from Germany (NOS) so I'm going -1.15 with toe at + 0.05 +/- 05'. If it's not so weight dependent I might tell the shop to calibrate with 70kgs either side, then leave the weights out allowing for future sag as it ages and settles.
Terry, that's interesting as it looks like it had shifted from where I had it set (-1.10) by the local WIM agent.
Rear has also been lowered with NOS MV6 so for thrust angle and camber, is rear toe best set at 0.00 ?
I found your set up by Fcm wheel alignment documentation 07/08/2012 £50 total (sounds cheap to me) and they reset it from L-2.00 R-0.5 fo 1.1 both sides. It may be my rotten measurement, hope not. I did the first car using the brake discs, realised there was scope for error so did the second car (X168) on the wheel screw hole flanges.
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Thanks. I've often wondered why we don't. :y
It's not currently easily possible to make a balljoint type bush, which is what the oe bush is, without either moulding or using a lump/block of poly that stresses the arms. Al's attempted solution is the best I've seen so far, but I wouldn't fit it. Sorry but no way.
A metal ball joint could be pressed in, if it could be sealed from the elements and not rust, but that would also be so harsh it's not worth the trouble.
At the other end Of the scale we have Al's solution. A combination of poly and a ball joint will be needed IMO. With a seal to keep the gall joint greased. Not so straightforward.
So, for me. Back to GM bushes.
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I struggle to understand the intended behaviour of the Omega wishbone. The front rubber joint allows primarily rotation round the horizontal bolt; the rear joint allows the wishbone to rotate around the vertical bolt and also up and down motion as dictated by the front joint. The vertical pivot rotation in turn requires the front joint to yield sideways. I am sure Adam Opel knew what he was doing, and am surprised that the rubbers can be replaced with polythene bushes behaving differently.
Is this arrangement common to other Mcpherson strut rubber mounted wishbone layouts?
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I struggle to understand the intended behaviour of the Omega wishbone. The front rubber joint allows primarily rotation round the horizontal bolt; the rear joint allows the wishbone to rotate around the vertical bolt and also up and down motion as dictated by the front joint. The vertical pivot rotation in turn requires the front joint to yield sideways. I am sure Adam Opel knew what he was doing, and am surprised that the rubbers can be replaced with polythene bushes behaving differently.
Is this arrangement common to other Mcpherson strut rubber mounted wishbone layouts?
Suspension movement, and toe in/out due to braking.
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I struggle to understand the intended behaviour of the Omega wishbone. The front rubber joint allows primarily rotation round the horizontal bolt; the rear joint allows the wishbone to rotate around the vertical bolt and also up and down motion as dictated by the front joint. The vertical pivot rotation in turn requires the front joint to yield sideways. I am sure Adam Opel knew what he was doing, and am surprised that the rubbers can be replaced with polythene bushes behaving differently.
Is this arrangement common to other Mcpherson strut rubber mounted wishbone layouts?
Suspension movement, and toe in/out due to braking.
On braking the wishbones will rotate about the rear vertical bushes, limited by the front bushes. I imagine the track rods will then cause the front wheels to toe-in, as Opel intended. If the front bushes are polythene, this will not happen. Am I right?
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I struggle to understand the intended behaviour of the Omega wishbone. The front rubber joint allows primarily rotation round the horizontal bolt; the rear joint allows the wishbone to rotate around the vertical bolt and also up and down motion as dictated by the front joint. The vertical pivot rotation in turn requires the front joint to yield sideways. I am sure Adam Opel knew what he was doing, and am surprised that the rubbers can be replaced with polythene bushes behaving differently.
Is this arrangement common to other Mcpherson strut rubber mounted wishbone layouts?
Suspension movement, and toe in/out due to braking.
On braking the wishbones will rotate about the rear vertical bushes, limited by the front bushes. I imagine the track rods will then cause the front wheels to toe-in, as Opel intended. If the front bushes are polythene, this will not happen. Am I right?
Braking causes toe out. Hence the static toe setting is a minus figure. -0.05 each side, -0.10 combined. Ime polyurethane bushes allow a nearer zero setting before they go positive. So less scrub (minimal already) and better stability in theory.
Obviously this is different for front wheel drive, as the front wheels pull ahead of the car as well as being pulled to the rear on the brakes.
Wishbone Yaw is the main (effective) concern on the rear bush. Poly helps minimise this over the softer rubber oe bushes. Suspension set up affects vertical wear. So softer suspension driven hard will give the rearward bush a much harder time.
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Thanks Chris. I would have designed it with both bolts horizontal and in line, that would have allowed normal wishbone motion with no yaw, been easier to make and easier to change. There is some cunning plot in the present design and I don't understand it.
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The Omega arrangement allows a certain amount of waftability rather than outright control... To drive there's a definite line between soft/wallowy and precision. Noticeable when you drive around a familiar bend at a sedate pace, and then attack the same bend at a far higher pace.
Sedately the car will waft around the bend with no fuss, but press on and the suspension loads up and the car tucks in and gets on with it (tyres permitting of course) :y
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Thanks Chris. I would have designed it with both bolts horizontal and in line, that would have allowed normal wishbone motion with no yaw, been easier to make and easier to change. There is some cunning plot in the present design and I don't understand it.
That rearward bush is, IMO, a shit idea. But then, when considering the design, and what a suspension joint has to do in a passenger car Ie pivot AND damp out vibration while STILL giving an acceptable level of precision to the driver and be cheap to produce, there's only one outcome.
The bush as genetic item is, like suspension itself, is infinitely tunable. They can have oil bladders, and voids and insets to limit and control comfort and movement in various directions.
Welcome to the world of compromise.
Next car will have a double wishbone front set up. Hopefully. Worst thing about omega suspension is the lack of control of camber throughout the suspension stroke. Hence the shoulder wear etc. handling degrades far too quickly as the tyres wear as a result.
...and through driving other members cars I see on my drive for suspension work, that's not as a result of driving style either.
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I can assure you though, a twin horizontal bush will be MUCH harder as far as ride goes. It's a set up that offers far less give. (Or much needed control in front wheel drive cars for example)
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There is no WIM near enough for me SA19 8LS to visit. I've recently done a wishbone and drop link change and my tracking needs looking at. Local ish ATS have the equipment to do 4 wheel alignment. If I take it to them what settings should I ask them to do with the car unloaded?
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Thanks for all thoughts Chris. I wonder now if the vertical rear wishbone pin may be responsible for the tyre wear pattern on Omegas. Perhaps under braking both front wheels toe out and scrub off the inner tyre edges. If so no amount of careful setting up will correct it.
Do any other cars have vertical rear wishbone pins? If so, I wonder how their front tyres wear.
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Thanks for all thoughts Chris. I wonder now if the vertical rear wishbone pin may be responsible for the tyre wear pattern on Omegas. Perhaps under braking both front wheels toe out and scrub off the inner tyre edges. If so no amount of careful setting up will correct it.
Do any other cars have vertical rear wishbone pins? If so, I wonder how their front tyres wear.
Tyre wear issues on a well set up omega with oe suspension relate to a long (comfortable) suspension stroke, single wishbone suspension (cost), and a soft (again, comfortable ) front bush.
Poly FRONT bushes go a long way to Improve accuracy for the driver. Both in stearing and stability in a straight line, and most effectively on the brakes which gives much less darting about as the road imperfections pull the road wheel about due to a soft front bush. This with a slightly firmer FEEL to the front suspension. (It's not actually firmer, but is caused by the slightly lesser damping ability of poly over the oil bladders in the front rubber bush designed to damp out high frequency vibration)
The rearward vertical bush affects stearing feel far more, (apart from steering idler etc) as its part of the two parallel lines that must be constant in the steering set up. 1 the line of the steering tie rods obviously, but also 2, the line of the suspension (ignoring the hole in the subframe for the engine to sit in) that hold the hub and steering pin on the wishbone in position. Pin no play>wishbone no flex>Bush no play or tears but still allowing a pivot without transmitting vibration>bolt tightening must be correct>subframe>ditto the other side etc
But, and heres the thing Terry....we can't really criticise the tyre wear on the standard set up, when we have such (comparatively) vast inaccuracies in the diy set up methods used, as described here. ....Especially given the refusal to set the car set up correctly via a hunter hawk eye rig for full geometric set up. Castor, camber, toe at the front. Camber, toe and the all important thrust angle at the rear.
While I admire your desire to understand and replicate the correct ideals, I repeat, it is NOT possible to confirm without doubt that the settings are correct going by anything seen here. So given that fact, one can't tell if any tyre wear or handling issue is down to set up or design, component failure, or whatever, when not starting from the same "bible" as any other car here.
From experience it is very difficult to keep an omega on, what I would call, a straight line(although I am fussy in that regard over others here). There are way too many variables from tyre size and design, through set up and interpretation of those figures even with the correct gear, to component quality and wear.
Get it set up correctly. Then go from there.
Rule no 1 in development of any machine. Achieve the manufacturers spec FIRST. OOF has achieved that over the years AND gone on to further refine those figures with the help of wheels in motion to the point that the standard figures in Haynes are now considered completely obsolete as a result. So the problems you have are;
Working to obsolete data
Working with too many variables on that data
Working with inaccurate methods
The best anyone can hope to achieve AND CONFIRM as correct with diy is to minimise tyre wear prior to set up on a hunter rig. Or there is a risk of premature tyre wear as you are quite rightly concerned about. :y
Having said all that though, that's not to say we shouldn't try, and have a go. So hats off to you Terry. I hope this isn't taken as overly negative, but more of a pointer as to what we are actually up against. :y