I would go with a 6 inch backing plate. That is what I use for my 6 1/2 pads. I have used a 5inch backing plate before, and found the 6inch to work better. :waxing:
Meguiar's recommends a 5" backing plate for their 6.5" pads. However, either size will work...it boils down to what's more comfortable for you. I like the 5" plate on both my PC and Makita.
Whatever you choose, make sure the backing plate is more then covered by the velcor on the pad. Otherwise, the PC eats into the back of the pad, quickly destroying it.
