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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.