As most of you will know, the strut towers have slotted holes to allow for some camber adjustment if the alignment pin is removed from the OE upper strut mount. The alignment pin centers the mount in the slots, meaning that by removing the pin you can get approximately ±0.25 degrees of adjustment from the stock -0.5 degrees.
OE Strut Mount with Alignment Pin
Ground Control Street camber plates incorporate a stainless steel pointer plate that allows field adjustment to repeatable values. The only problem is that unless the pointer plate is fixed relative to the strut tower, it is free to move within the ±0.25 degree range permitted by the slots in the strut tower – not good for repeatability.
Ground Control Street Camber Plate
Ground Control has thought of that, but they don’t provide any installation instructions so you need to figure out their solution on your own. The pointer plates are “handed” and need to be installed chamfered edge up. They incorporate 10-32UNF tapped holes that permit installation of an alignment pin (not supplied) that bias the pointer plates at the inboard limit of the slotted hole in the strut tower. You just need to find a suitable pin.
A fillister head screw would probably work, but my solution was to enlarge the holes to ¼” and to TIG weld in a stainless ¼” socket head cap screw in the correct hole. The weld must be ground flush on the bottom to prevent it gouging the camber plate.
Modified Pointer Plates
The modified pointer plates bias the plates towards maximum negative camber in the slots.
Pointer Plate biases Camber Plate towards maximum negative camber
With M3 front suspension arms, my front camber is approximately -1.5 degrees with the pointer set to zero on the camber plate.
Camber Plate at zero, M3 Suspension Bits, -1.5° Camber (aprox)
I can adjust the camber plates to a reading of -2 for an actual camber of approximately -3.5 degrees before the upper spring perches (for OE springs) come uncomfortably close to the inside wall of the strut tower.
Pointer at -2 degrees
Spring Clearance with pointer at -2 degrees