I'm not clear on how the Economy gauge and the deco magnetic gauge attach to the wheel - do the magnetically stick to the bearing dust cap? Or some machined surface on the hub? Do you pull your center caps off to do the alignment? The instructions linked in the ordering page didn't make it clear to me.
Also - what wheel diameter range does the economy gauge work for?
I don't have one, but I'd assume the small economy gauge is to be used at the outer part of the rim (not at the center of the wheel). It would have to be oriented vertically, so the two contact points are one directly above the other. It doesn't seem to show a level for doing that, so using a separate level or maybe rigging up a plumb bob would be the way to do that. It could just be held in place by hand for the measurement, probably no real need to attach it.
I was wondering about alternate ways (read: cheap
) to do this, and thought of a method using just a simple small level (it just has to be smaller than the diameter of the inner rim points- a 12" level probably would be universal enough to use on all cars).
Using the level vertically and the bubble level going front-rear of the car, locate two points on the rim that are perfectly vertical, and dab it with a sharpie or otherwise just remember where it is.
Then flip the level so the bubble level goes left-right of the car, keeping the top tip of the level at the same point, and move the bottom of the level out until the bubble level is centered. Using a digital caliper, measure the distance from the tip of the level to the wheel contact point. This assumes negative camber, if it's set up for positive camber, then just hold the bottom tip of the level at the rim and move the top out until the bubble's centered.
This measurement (call it X) and the length of the level (calling it L) can now be used to calculate the camber, based on the formula for the inverse cosine of :
(2 x L squared - X squared) / (2 x L squared).
Or avoid all the math and just use this
online calculator, selecting the "3 Sides" calculation.
Enter the length of the level into A and B, and the caliper measured distance into C. The calculated value of C should be the camber angle.
If you're always shooting for a particular angle, you could use the S-A-S mode and enter the angle you want, and calculate the required Side c. Then just get a fixed shim or something of the right length, and adjust things until it shows level with the shim in place.
Now this is only something I've just thought up and just found this forum while poking around looking for ideas, so if anyone can take a look and see if this is reasonable, let me know
edit- Well, just looked at the wheel and realized this won't work by itself because the wheel is convex and won't allow a straight edge to be put between the two points on the rim. So that's why all the real tools have extensions to reach the rim-
Otherwise that economy gauge seems the most cost effective way to go about it, so I may get it to try out anyway-
I stand happily corrected. Now I NEED one!
