I was figuring same timer as one of the other 2 earth-fire rares. Here's the list of what you can expect to be seeing a lot of (grabbed from breeding list and added Chimpala):
Earth/Red ------- Armordillo (12Hrs)
Earth/Red ------- Rampage (13 Hrs )
Earth/Red ------- Volcamel (14Hrs)
Earth/Red ------- CHIMPALA (14Hrs)
Earth/Red ------- Magmacore (15Hrs)