DIY Camber Checking

this is how i do the camber, incidentally a flat surface is needed for both camber and tracking! I use a long spirit level and a short spirit level to get a good virtical line. parallel to the centre line of the straight wheel.
Once i am happy its nice and virtical i measure the distance as shown below..
I then measure the distance at the top of the rim making sure not to knock the spirit levels, its a bit fiddly and i usually have to do it a few times before im happy
I then subtract the lower measurement from the upper one and use this site http://www.engineersedge.com/calculators/triangle_solution_3.htm
inputing the length from the top to the bottom of the measurement, ( which is close to the rim size) and the result of the subtraction sum i did, this gives us 2 sides of a triangle, from this you can calculate the third side, and then the angles! et voila! heres an example: length from top to bottom of rim at the points we are taking the measurements from =12 inches, result from subrtracting the bottom measurement from the top measurement = 0.21 inch, input the data and we get a result of just about 1 degree of camber! if the top measurement is bigger than the bottom measument then you have negative camber, if the top measurement is smaller than the bottom then you have positive camber!