Molded-composite back upright features integral 0° of outboard toe to improve traction and prevent suspension geometry changes in serious crashes. Features two roll center jobs on top of back upright. Accommodates little but robust 5x10 ball-bearings for minimized unsprung fat.
Medium rigidity (labeled “M”) particularly optimized for rubber-tire race.
Use on both left and right sides associated with vehicle. Are also employed for foam tires.