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[terry paget]

I understand from Al that Wheels in Motion (WIM) adjust suspension geometry with the car suspended and all wheels in the air, setting parameters to pre-calculated settings so as to be correct when car is on its wheels. Does anyone know how Opel do it in the factory? I expect they support the car under wishbones and trailing arms, with the 70 kilos in the front seats and full fuel load, as Haynes states.

That is how I set my toe-in, as said before. It now occurs to me that setting my front wheels parallel to rear also allows me to measure rear wheel toe-in, and even reset it if I can adjust the rear track rods.

Can I not also set the camber at the same time?

Camber is not critical for handling or feel, but affects tyre wear. With car supported under wishbones at wheel end, all I need do is loosen the strut to hub bolts and tap it with a hammer to adjust it. Question is, how do I measure it?

[05omegav6]

Either using several thousand pounds of 3d laser alignment kit or a purpose built assembly jig which has been calibrated to your car

Rear track rods adjust camber and toe at the simultaneously, which compromises things somewhat

[chrisgixer]

As said before, on other threads where this practice has been mentioned (as its not possible to support the wishbone on the wheel end, as the wheel is in the way, ) there is a very real chance of bending the wishbone if it's taking the weight of the car.

Don't do it. ( I'm not actually bothered if you do. The important thing I have made the point, so my conscience is clear. The rest is up to you)

[Nick W]

Camber is probably the easiest measurement to make, as it's taken directly from the wheel. I used a cheap, magnetic digital bevel-gauge(about £20, and used for setting work at an angle in the milling machine), stuck to a length of 50mm angle cable-tied upright across the wheel rim. The gauge was zeroed on a longer piece of angle positioned between the wheels. We adjusted the camber by prying the wheel around with a jackhandle in the spokes; tightening the bolts with the car on the ground was tricky.

When I finally got around to having the geometry set properly, the machine gave the same figures I'd set it to.

What doesn't help is that adjusting the tracking, and mine was massively out, also tweaked the camber settings. This is one of the things that makes doing a complete setup very difficult using DIY equipment.

As for how they're done at the factory, there's no way that the cars would come off the production line and then be aligned by a couple of blokes with spanners; the suspension subassemblies like the struts and hubs would have been assembled in jigs before being fitted to the car. I suspect that parts like cambelts were fitted in a similar manner.

[terry paget]

Either using several thousand pounds of 3d laser alignment kit or a purpose built assembly jig which has been calibrated to your car

Rear track rods adjust camber and toe at the simultaneously, which compromises things somewhat

Thanks, Al. Yes, I can imagine the car coming down the line, with the strut to hub bolts half tight, then jigs grabbing the wheels, heaving them to the right angle, then the bolts torqued up. No need to measure anything, the setting is in the kit.

I think it would need a man to adjust the toe-in, aided by optical/laser reading kit. And I wonder if the wheels would be on the ground at this stage, and how the car was supported, and loaded.

[terry paget]

As said before, on other threads where this practice has been mentioned (as its not possible to support the wishbone on the wheel end, as the wheel is in the way, ) there is a very real chance of bending the wishbone if it's taking the weight of the car.

Don't do it. ( I'm not actually bothered if you do. The important thing I have made the point, so my conscience is clear. The rest is up to you)

Thanks for your concern Chris, which is noted. Wishbones are robust items, which endure substantial forces in many directions. I never had any real fear that I would bend one, and I have done this often enough to be confident that it ain't going to happen. As shown before in photographs, the wheel is dished allowing the support to be very near the ball joint. 

[tidla]

http://vid1114.photobucket.com/albums/k536/tidla1/20121228_171727_zpsab384861.mp4

This is my home made tool for setting up the camber.

The steel plates on the floor are level and the gauge calibrated from this.

The video if i remember correctly shows how much adjustment is available once the bolts are slack.

Camber was set up with the weight of the vehicle on the wheels and as mentioned using a method to pull out the top of the wheel.
 

[05omegav6]

Either using several thousand pounds of 3d laser alignment kit or a purpose built assembly jig which has been calibrated to your car

Rear track rods adjust camber and toe at the simultaneously, which compromises things somewhat

Thanks, Al. Yes, I can imagine the car coming down the line, with the strut to hub bolts half tight, then jigs grabbing the wheels, heaving them to the right angle, then the bolts torqued up. No need to measure anything, the setting is in the kit.

I think it would need a man to adjust the toe-in, aided by optical/laser reading kit. And I wonder if the wheels would be on the ground at this stage, and how the car was supported, and loaded.

If you know the datum, then adjusting the geometry to allow for wheel position in space relative to the shell at standard ride height, then the relative position unloaded can then be simply calculated... this is how Wheels In Motion do it, and why they're worth every penny imho

When the adjustments are made with the car jacked, the gauges are all over the shop, but a tweak here and a nudge there and once the car is back on the deck, it's all spot on. The clever bit is that the Hawkeye machine is able to not only map the position of each wheel in 3 dimensions, it is also able to recognise the relative positions of all four wheels and translate all the data into a clear picture on the screen The art is translating the tweaks into the ideal settings.

Also, if using the board method to track the car front to rear, bear in mind that both axles toe in...

[terry paget]

Camber is probably the easiest measurement to make, as it's taken directly from the wheel. I used a cheap, magnetic digital bevel-gauge(about £20, and used for setting work at an angle in the milling machine), stuck to a length of 50mm angle cable-tied upright across the wheel rim. The gauge was zeroed on a longer piece of angle positioned between the wheels. We adjusted the camber by prying the wheel around with a jackhandle in the spokes; tightening the bolts with the car on the ground was tricky.

When I finally got around to having the geometry set properly, the machine gave the same figures I'd set it to.

What doesn't help is that adjusting the tracking, and mine was massively out, also tweaked the camber settings. This is one of the things that makes doing a complete setup very difficult using DIY equipment.

As for how they're done at the factory, there's no way that the cars would come off the production line and then be aligned by a couple of blokes with spanners; the suspension subassemblies like the struts and hubs would have been assembled in jigs before being fitted to the car. I suspect that parts like cambelts were fitted in a similar manner.

Thanks for that, Nick. Were you able to pry the wheel about with it on the ground? Were you able to tighten the nuts with the wheel on the car?

Haynes says correct setting is -1 degree 40 minutes plus or minus 45 minutes. Does this mean top leans in or out?

[terry paget]

http://vid1114.photobucket.com/albums/k536/tidla1/20121228_171727_zpsab384861.mp4

This is my home made tool for setting up the camber.

The steel plates on the floor are level and the gauge calibrated from this.

The video if i remember correctly shows how much adjustment is available once the bolts are slack.

Camber was set up with the weight of the vehicle on the wheels and as mentioned using a method to pull out the top of the wheel.

Thanks Tidia. I applaud your kit. What is the measuring device I see? Looks like a digital spirit level.

[terry paget]

Either using several thousand pounds of 3d laser alignment kit or a purpose built assembly jig which has been calibrated to your car

Rear track rods adjust camber and toe at the simultaneously, which compromises things somewhat

Thanks, Al. Yes, I can imagine the car coming down the line, with the strut to hub bolts half tight, then jigs grabbing the wheels, heaving them to the right angle, then the bolts torqued up. No need to measure anything, the setting is in the kit.

I think it would need a man to adjust the toe-in, aided by optical/laser reading kit. And I wonder if the wheels would be on the ground at this stage, and how the car was supported, and loaded.

If you know the datum, then adjusting the geometry to allow for wheel position in space relative to the shell at standard ride height, then the relative position unloaded can then be simply calculated... this is how Wheels In Motion do it, and why they're worth every penny imho

When the adjustments are made with the car jacked, the gauges are all over the shop, but a tweak here and a nudge there and once the car is back on the deck, it's all spot on. The clever bit is that the Hawkeye machine is able to not only map the position of each wheel in 3 dimensions, it is also able to recognise the relative positions of all four wheels and translate all the data into a clear picture on the screen The art is translating the tweaks into the ideal settings.

Also, if using the board method to track the car front to rear, bear in mind that both axles toe in...

Thanks Al. My problem with measurement with body supported and wheels hanging down is that on a McPherson strut lower wishbone layout layout camber varies with suspension position. With body supported front wheels hang down by gravity, but are supported by the wishbone vertical bush, so where it hangs will depend on the age of the vertical bush.
I do not doubt the quality of the measurement at WIM, my concern is the software to correct for all these factors.

As you say, with a rear semi-trailing arm, adjusting the track rod affects both toe-in and camber. Unless the car has been crashed it should not have moved, mine have always looked parallel to front, anyway the rear track rods are so hard to free that I leave them alone.

[chrisgixer]

if adjusting wheels on the floor the problem you have is the contact patch of the tyre obviously is working against you and holding tension in the setting. As the wheel is leaned in at the top to adjust, the bottom of the wheel wants to go the opposite way and move out at the bottom, except the side wall and tyre are fixed so flex in the tyre wants to spring back to the original position, and to an extent the car will move over and tension the other tyre as well.

So for this reason, after each adjustment for camber AND toe, the car has to be rolled back and forth to allow the tyre contact patch to unload and re set to the new track width.

Hawkeye rigs have sliding plates that allow swivel and track movement. Even with these they still roll the car back and forth after adjustment to allow the content patch to find its natural position.

The sofware measures the wheel position at rest wheels loaded. Then notes the amount of adjustment needed. The car is then raised and measured again wheels hanging. The operator can then adjust to the differance between the two measurements taken wheels loaded, when subtracted or added to the wheels hanging position.

Once adjusted the car is dropped down again, rolled back and forth to remove any pinch on the track of the tyres to give the natural wheel position, then re measured. If the software had done its job adding and subtracting, the final position should now be correct.

....and they almost always are, IF the operator has been accurate enough with the amount of movement, AND the target settings are set to a decent tolerance.

what are your target setting Terry?

[Nick W]

Terry, the job was done with the car on its wheels, in the street. We used the handle from my workshop jack as a lever, which was easy. Tightening the bolts like that is awkward but doable. Doing the job on a fourpost ramp or over a pit would be much simpler. It's a two-man job however you do it.

I can't imagine setting the camber with the suspension unloaded, there must be a huge amount of trial and error involved. Particularly when you consider the precision required. According to my 'gauge' there is about 5degrees total adjustment. Tidla's device is a more sophisticated version of what I used, mainly because it allows for some proper calibration.

What is interesting is watching how the various readings change as specific adjustments are made; correcting the toe on my car(which was 6mm on one side and 13mm on the other!) added about 10minutes of camber.

[chrisgixer]

Indeed, as Nick says, and has been well documented on here for any search, the subframe is (must be) adjusted first if needed to achieve castor, then camber must be set next as the toe moves if camber is adjusted, so toe is set last.

This tells us that the track rods are are not set at the same height as the pivot centre for camber adjustment.

So you see, with all these things to juggle, it's only possible to get it accurate on a set up rig.
But more importantly..... Most Certainly it is only a set up rig can that can confirm your work as accurate. So obvioisly if checking on a rig, they will charge, so may as well leave the final increments to them.

[terry paget]

if adjusting wheels on the floor the problem you have is the contact patch of the tyre obviously is working against you and holding tension in the setting. As the wheel is leaned in at the top to adjust, the bottom of the wheel wants to go the opposite way and move out at the bottom, except the side wall and tyre are fixed so flex in the tyre wants to spring back to the original position, and to an extent the car will move over and tension the other tyre as well.

So for this reason, after each adjustment for camber AND toe, the car has to be rolled back and forth to allow the tyre contact patch to unload and re set to the new track width.

Hawkeye rigs have sliding plates that allow swivel and track movement. Even with these they still roll the car back and forth after adjustment to allow the content patch to find its natural position.

The sofware measures the wheel position at rest wheels loaded. Then notes the amount of adjustment needed. The car is then raised and measured again wheels hanging. The operator can then adjust to the differance between the two measurements taken wheels loaded, when subtracted or added to the wheels hanging position.

Once adjusted the car is dropped down again, rolled back and forth to remove any pinch on the track of the tyres to give the natural wheel position, then re measured. If the software had done its job adding and subtracting, the final position should now be correct.

....and they almost always are, IF the operator has been accurate enough with the amount of movement, AND the target settings are set to a decent tolerance.

what are your target setting Terry?

Target settings are Haynes -1degree 40 minutes plus or minus 45 minutes, 70 kilos (a wife) in either front seat and full tank of petrol. I still don't know if that means lean in or lean out.

[chrisgixer]

Yeah see, those settings are terrible. Based on the vx tollerances that are so wide as to be utterly useless.

Do yourself a favour Terry. Get it set up correctly. (Or at least get one set up correctly and measure that car and transfer those settings to the others)

And have a search, this subject has been done to death over the years. All the info is on here somewhere.

[aaronjb]

Terry, negative camber means the wheel leans in at the top.

The last cars with positive camber probably had wooden cart wheels..

[05omegav6]

Once the hub to strut bolts are tightened, the camber is set. It doesn't vary whether the suspension is loaded or not. What changes is the datum from which you measure everything...

I could build a jig to allow me to set the camber upside down on a table, as the camber angle is simply the differential between the hub face and the line from the ball joint through the centre of the shock. Haynes dimensions are wrong as they are based on Vauxhalls settings for a brand new car and allow nothing for wear and tear to any components or the overall structure of the car and also the ever variable dimensions of any replacement components.

If you set the camber as it suggests you will encounter some interesting inner edge tyre wear

Ideal is 1°10, with castor of around 5° and toe in of 0°05 at the front. (Castor might vary from side to side slightly, and only shifting the subframe can sort it, all the other dimensions must be symetrical though)

Rears will fall where you can get them, but target for 1°30 camber and toe as close to 0°05 as you can get it. Whatever the rear ends up at, the thrust angle MUST be 0°.

[05omegav6]

Incidentally, the final set up of the factory cars was done by the dealer as part of the PDI

[Nick W]

Negative camber means that the top of the wheel leans in.
The stated figure is quite a large amount for camber.
The tolerance of plus/minus 45minutes is enormous, and should be regarded with scepticism.

[tidla]

And havin a laff negative camber

[chrisgixer]

Once the hub to strut bolts are tightened, the camber is set. It doesn't vary whether the suspension is loaded or not. What changes is the datum from which you measure everything...

I could build a jig to allow me to set the camber upside down on a table, as the camber angle is simply the differential between the hub face and the line from the ball joint through the centre of the shock. Haynes dimensions are wrong as they are based on Vauxhalls settings for a brand new car and allow nothing for wear and tear to any components or the overall structure of the car and also the ever variable dimensions of any replacement components.

If you set the camber as it suggests you will encounter some interesting inner edge tyre wear

Ideal is 1°10, with castor of around 5° and toe in of 0°05 at the front. (Castor might vary from side to side slightly, and only shifting the subframe can sort it, all the other dimensions must be symetrical though)

Rears will fall where you can get them, but target for 1°30 camber and toe as close to 0°05 as you can get it. Whatever the rear ends up at, the thrust angle MUST be 0°.

Camber is indeed fixed in relation to the shock, and this is set and immoveable, ignoring flex and tyre deflection. However that measurememt alone is not important. The important bit is the camber setting in relation to the road.

When camber is said to vary, this is in relation to suspension travel. The wishbone works on a radius, and as such must pull the stub axle assembly inboard and outboard as the suspension ruses and falls.

Therfor camber, in relation to the road, does vary. This is why sport suspension is preferred over Elite suspension for enthusiastic drivers. As the tyres stay in contact with the road better, and wear  more evenly.

Prety sure that's what Terry meant by camber variation. Or camber deflection, as I call it, rightly or wrongly. The limits of McPherson strut suspension are revealed. Sadly. It needs at least another pivot somewhere, to keep the contact patch flatter, and run less camber generally.

[05omegav6]

Once the hub to strut bolts are tightened, the camber is set. It doesn't vary whether the suspension is loaded or not. What changes is the datum from which you measure everything...

I could build a jig to allow me to set the camber upside down on a table, as the camber angle is simply the differential between the hub face and the line from the ball joint through the centre of the shock. Haynes dimensions are wrong as they are based on Vauxhalls settings for a brand new car and allow nothing for wear and tear to any components or the overall structure of the car and also the ever variable dimensions of any replacement components.

If you set the camber as it suggests you will encounter some interesting inner edge tyre wear

Ideal is 1°10, with castor of around 5° and toe in of 0°05 at the front. (Castor might vary from side to side slightly, and only shifting the subframe can sort it, all the other dimensions must be symetrical though)

Rears will fall where you can get them, but target for 1°30 camber and toe as close to 0°05 as you can get it. Whatever the rear ends up at, the thrust angle MUST be 0°.

Camber is indeed fixed in relation to the shock, and this is set and immoveable, ignoring flex and tyre deflection. However that measurememt alone is not important. The important bit is the camber setting in relation to the road.

When camber is said to vary, this is in relation to suspension travel. The wishbone works on a radius, and as such must pull the stub axle assembly inboard and outboard as the suspension ruses and falls.

Therfor camber, in relation to the road, does vary. This is why sport suspension is preferred over Elite suspension for enthusiastic drivers. As the tyres stay in contact with the road better, and wear  more evenly.

Prety sure that's what Terry meant by camber variation. Or camber deflection, as I call it, rightly or wrongly. The limits of McPherson strut suspension are revealed. Sadly. It needs at least another pivot somewhere, to keep the contact patch flatter, and run less camber generally.

This should be a single, repeatable measurement for any given spring length from the factory, hence the VX settings. But factor in ten+ years of wear and abuse and horrendous variation in aftermarket parts tolerances and we arrive at WIMs settings as detailed above

[chrisgixer]

Once the hub to strut bolts are tightened, the camber is set. It doesn't vary whether the suspension is loaded or not. What changes is the datum from which you measure everything...

I could build a jig to allow me to set the camber upside down on a table, as the camber angle is simply the differential between the hub face and the line from the ball joint through the centre of the shock. Haynes dimensions are wrong as they are based on Vauxhalls settings for a brand new car and allow nothing for wear and tear to any components or the overall structure of the car and also the ever variable dimensions of any replacement components.

If you set the camber as it suggests you will encounter some interesting inner edge tyre wear

Ideal is 1°10, with castor of around 5° and toe in of 0°05 at the front. (Castor might vary from side to side slightly, and only shifting the subframe can sort it, all the other dimensions must be symetrical though)

Rears will fall where you can get them, but target for 1°30 camber and toe as close to 0°05 as you can get it. Whatever the rear ends up at, the thrust angle MUST be 0°.

Camber is indeed fixed in relation to the shock, and this is set and immoveable, ignoring flex and tyre deflection. However that measurememt alone is not important. The important bit is the camber setting in relation to the road.

When camber is said to vary, this is in relation to suspension travel. The wishbone works on a radius, and as such must pull the stub axle assembly inboard and outboard as the suspension ruses and falls.

Therfor camber, in relation to the road, does vary. This is why sport suspension is preferred over Elite suspension for enthusiastic drivers. As the tyres stay in contact with the road better, and wear  more evenly.

Prety sure that's what Terry meant by camber variation. Or camber deflection, as I call it, rightly or wrongly. The limits of McPherson strut suspension are revealed. Sadly. It needs at least another pivot somewhere, to keep the contact patch flatter, and run less camber generally.

This should be a single, repeatable measurement for any given spring length from the factory, hence the VX settings. But factor in ten+ years of wear and abuse and horrendous variation in aftermarket parts tolerances and we arrive at WIMs settings as detailed above

Mv6 or sports suspension wim, for example, recommend -1.15.

Having presented a car with brand new everything in the suspension, I fail to see how -1.45 would be acceptable at any stage.

New, old, shagged, lowered, raised, rough road package or lowered sports chassis, at no point is 1.45 of use to anyone. Never mind the +/- 45 tollerances on top of that.

-2.30 and still in the green? I don't OPPSING think so.

That tells me there IS no "method" that opel use to set up an omega. They just give themselves tolerances to allow them to throw the car together any old how, and be done with it.

Having said that, both wim and Micheldever quite often have new vehicles in for set up, prior to delivery to the customer, so opel are not alone.

[terry paget]

Thank you all for your input. I am a wiser man.
Al, I am afraid you are wrong, as Chris observes, about camber being constant with a McPherson strut/lower wishbone front suspension. It must vary by several degrees between central position and upper and lower extremes of movement. I imagine with full tank and two 70 kilo wives in the front seats the suspension is near the middle of its travel, and set at -1 degree 40 minutes. It will vary to +1 or 2 degrees at top or bottom of travel. To avoid this variation it would need double wishbone front suspension, which would require much more maintenance and not handle much better. Many, probably most, modern cars use McPherson strut front supension. Tyres will wear on the shoulders.

[05omegav6]

The position of the hub and therefore wheel in relation the the line of the shock absorber is fixed and therefore constant when the bolts are tightened. Not debatable.

The relative camber does indeed alter with suspension travel (as does all the suspension geometry ), hence the setting be done in such a way that the camber is optimised with the car at rest on a level surface.

[tidla]

Vag group use a Four link suspension set up, (think double wishbone) but because of two ball joints top and bottom it doesn't turn like you would expect when turning the wheel at the road wheel. Yes more maintenance, but yet to see one with mad tyre wear when all is correct.

[Nick W]

Vag group use a Four link suspension set up, (think double wishbone) but because of two ball joints top and bottom it doesn't turn like you would expect when turning the wheel at the road wheel. Yes more maintenance, but yet to see one with mad tyre wear when all is correct.

But it's even less maintenance friendly than the Omega, and also has a tendency to snap the links. Which is never good!

[chrisgixer]

McPherson strut is popular with manufacturers as its cheap and relatively maintanance free. But lacks wheel control and camber deflection is excessive. Ride can be choppy and inaccurate.

Double wishbone is more accurate, more compact, but more linkages means wear and loss of set up. Ride can be a bit hard with potentially less travel.

Most of which means suitability depends on how good the roads are. obviously a better surface allows less suspension travel and a firmer set up, if required.