You really need to post some pics of the arch position (both good and bad sides) and get some pics from under the arch too looking at the suspension strut.

when you state drop height where are you measuring?

Have you measured from the centre of the arch to the ground on both sides of the car on flat ground? I would doubt that the car is level if you are hitting arch one side.

I am more suspicious that if the spring platforms are the same height, then something could be missing from the above the spring so the car chassis is sitting lower as i mentioned before possibly the inner strut nut. get the measurements from each side of arch to the ground which will prove the height is different one side or not as the case maybe.

Should be measured from the outside lip of the arch to center of the hub or center point on the wheel as taking it from the ground can give you the rong hight,

tyre wear and tyre pressures will not be the same.

Edited 1 August, 201015 yr by JackDeath

Should be measured from the outside lip of the arch to center of the hub or center point on the wheel as taking it from the ground can give you the rong hight,

tyre wear and tyre pressures will not be the same.

That true, unless you have even tyre wear, correct tyre pressures and the ground is level of course.....