Silly Car Blog

ahhhh i think i just realised what you meant in your question anon

RCA = Roll Centre Adjusters

when you lower a car by changing springs and shocks you move the suspension geometry (control arm) and it can cause ‘bump steer’ and an unsettled ride. By putting a spacer between the strut and the control arm you put the geometry back into place without affecting ride height. this should ONLY be done on a properly lowered car and the RCA size should match the height difference from stock to lowered for best results

i’ll post a descriptive pic when i get a chance, bit busy atm