We have what you need, but if your 2018 Coachmen Mirada Motorhome is built on the Ford 20,500 GVWR chassis, the Roadmaster Rear Anti-Sway Bar, # RM-1139-149 is not the correct component. That item is for the 22K chassis. You need the Roadmaster Rear Anti-Sway Bar, # RM-1139-145 for your Ford 20,500 GVWR chassis. view full answer...