An EV spread of 60 HP / 244 Atk / 204 SpD might be better for Rhydon. It makes Rhydon considerably better at taking Special based attacks, without losing too much on Physical Defense. Metagross Meteor Mash is a 2HKO, and Garchomp multitarget Earthquake is a 3HKO, regardless of if you have 0 or 252 HP EVs. With 60 HP, you can take a Gem Close Combat from Hitmontop guaranteed. With 60 / 204, you can take a Gem Draco Meteor from Latios guaranteed.
Just another rainy day on the train...
VGCS Jaunary International, 165W-30L-27D/C, 1873
, 13th Place
VGC 2013 Winter Regional, Salem OR, 1st Place