On Thu, 8 Dec 2016 20:12:14 -0000 (UTC), John Harmon
wrote:

Steve W. actually said:

Q: What accuracy is *needed* to measure camber at home?
.01 degree or better.

Thanks for that answer because this is a critical number we must know to do
any aligment reasonably well.

If everyone concurs that 0.01 (one hundredth) of a degree is the desired
accuracy, I can work with that.

One problem with alignment is that we have to be intelligent about
converting units because I found this document where, on page 11, it says:

Quote:

Quick-acting clamp + measuring sensor + computer = 1' at a measuring range of ? 3? (all BMW vehicles are within that ? 3? measuring range).

http://www.bimmerboard.com/members/s...tem%5B1%5D.pdf



But I don't (yet) know how to convert 1 minute to inches.
Does anyone want to take a stab at how to run that conversion?
Pythagorus' theorem -, or better yet, trigonometry. Or a triangle
calculator like http://www.cleavebooks.co.uk/scol/calrtri.htm Solve a
triangle. You know (from your measurements) the base of the triangle
(distance from spindle) and the height (difference between the
projected line and "straight"), or the base and 2 angles (the desired
angle and 90 degrees) to calculate the height. One way tells you what
angle you have, the other gives you the distance measurement you WANT.


What other gotchas will we need to look at to successfully measure wheel
camber using a mobile device in a typical garage setup?

Your biggest problem is getting your head around all the concepts.

How to attach the device to the wheel/hub.

It seems to me that a "jig" of some sort needs to be made so that there is
a plane on the wheel that is (very precicely) parallel to the wheel to the
same 0.01 inches that we need for accuracy.

My initial idea is to take this concept to that 0.01 degree:
http://i.cubeupload.com/6CPUl7.jpg


On some vehicles it CAN be that simple -- On others it is definitely
a wee bit more complex, but you have the idea.
Maybe bolt a flat steel plate to the wheel lugs (luckily, one of my cars
uses lug bolts so I can just use longer bolts but my other car uses lug
nuts which may make that flat plate bolting on more difficult).

And the length of the studs/bolts gets critical - not to mention it
works best with 4 or 6 studs - not so good on odd numbers like the
common 5, or the less common 3 stud wheels.