Pair of 30mm rear drop knuckles for Scion FRS, Subaru BRZ, Toyota GT86 and GR86. Requires our MAX upper control arms and toe rods for installation (sold separately). Improve suspension geometry on lowered cars OR use this to go even lower if your coilovers are already maxed out low! Includes dual caliper brackets built in. The unique shape of our RUCA and relationship between the drop knuckle and upper arm is built for clearance, enough for the 1000hp axles & hubs from Driveshaft Shop. The OEM RUCA ball joint gets maxed out when the car is lowered, and it's downward facing hardware would run into the axle in our drop knuckle so the joint orientation is completely changed in our knuckle/arm set. Our design will allow your suspension to droop and compress without binding like the stock suspension would. You can add a little more negative camber or take out a lot for superior drifting traction & tire wear (-10mm to +50mm length Upper arms). The 30mm roll center corrected drop knuckle restores handling geometry lost on lowered cars & has caliper options like our front knuckles: Either OEM foot-brake and Z32 hand-brake OR dual Z32 reproduction calipers we sell for $215/pair loaded. Compatible with drum parking brake. Requires at least the backing plate to be used for proper hub spacing. This set features 10 low torque, maintenance free, PTFE lined spherical bearings. Forged fork connections bolted onto the robust knuckle casting are an easily replaceable, intentional focal point for crash energy. **Some 17 inch wheels do not clear, by known example Enkei RPF1 17x8+35 fits but 17x9+45 has inner barel in interference with the drop knuckle. We don't know every one piece wheel's inside shape but its safe to say all 18" and lower offset 17's are good. Drop knuckles will lower the rear of the car. So if you do not want a low ride height, you will need to be sure that you can lengthen your coilovers.