I always thought
Red roans were bays with roaning
& strawberry roans were chestnut with roaning
Blue roans black with roaning.
pretty much.. but.. the gene is roan and to some if you say bay with roaning, it means something different than bay roan. If you say "roaning" many people think of that as a broader term encompassing the rabicano roaning as well, such as exhibited by this mare. FV Alarazzl Rose by FV Fantasy Farwa x Razzldazzl Rose . She's obviously not a chestnut (strawberry) roan. She does have rabicano and sabino though on a flaxen chestnut base.