Originally started this thread in the e46 forum, but I thought I'd cross post it here to appeal to a broader audience -
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Been doing a lot of research into alignments and while I've learned much, but I haven't been able to come up with "definitive" answers for some fundamental technical questions:
* Why does BMW require the car to be ballasted for alignment?
* What percentage error is introduced if the car is aligned without ballast?
* What percentage error does a typical alignment machine inherently have?
* What percentage error does a typical alignment machine usually produce after accounting for errors induced by maintaince and/or training issues?
* Where in the tolerance range of the alignments were the cars typically set at the factory?
Anybody care to have a go?
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One other question has since come up:
* How much do the toe and camber angles change across the operating range of the suspension? That is, how what would be the difference between the measurements for a car in the following conditions: at rest, driving normally, hard cornering, and full compression?
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Here's a link to the original thread -
http://www.bimmerfest.com/forums/sho...d.php?t=111829
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| Reply » Alignment Technical Questions (2) |
Quote: | But 40 minutes is 2/3 of a degreee, so 0 - 2/3 degrees is a reasonable range for camber. | 0 to -2/3 is a reasonable range across which camber might be set depending upon one's preferences, but I don't think that correllates to the factory assembly tolerance.
Again, using my e46 for illustrative purposes, the front camber is adjusted by rotating the position of the strut across the slotted mounting holes. But to do so, you first have to remove a factory locator pin. The actual factory alignment tolerance would be determined by how tight a fit that pin has with the hole it protrudes through.
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| Reply » Alignment Technical Questions (2) |
Actually it is set by how closely the chassis is made to being straight. Although, if it is within the specfied tolerance range, everything is fine. It is conceiveable that a car could come form teh factory with one or both pins pulled to set teh camber correctly.
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| Reply » Alignment Technical Questions (2) |
jpr,
normally cross-posting is not a regular practice here and threads get closed. But I'll make an exception and leave this open this time.
If you feel that a thread would appeal a broader public next time, please post it in the General BMW forum rather than posting it twice.
Thanks for your understanding.
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| Reply » Alignment Technical Questions (2) |
Quote: jpr,
normally cross-posting is not a regular practice here and threads get closed. But I'll make an exception and leave this open this time.
If you feel that a thread would appeal a broader public next time, please post it in the General BMW forum rather than posting it twice.
Thanks for your understanding. | duly noted - and thanks
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Alignment Technical Questions (2)