The support beams on our A-arms also got beefier. At their thickest, stock a-arms are roughly 1/2” (12.7mm) thick, but taper down on both ends. That amounts to a loss of nearly 30% of their thickness at the outer hinge pins. Not with RPM! Our A-arms are a full 1/2” (12.7mm) over nearly their entire length! We only taper them slightly at the inner hinge pins (.45” or 11.43mm at their narrowest) to match the maximum size allowable of the inner hinge pin bosses. To compensate for that slight taper, we use four massive support beams instead of two