Well, Rhydon sucks, really bad choose damn. Let's rechoose?
If our set will have SD + RP, we'll only have two Slots to put Damage moves. We'll must choose between Earthquake/Stone Edge/Megahorn or some another move. It means that Rhydon will lack to kill something.
Lets do some analysis. If we sent out Rhydon (Eviolite counting on calcs), and use Swords Dance then the opponent switch in a properly Counter, what happens:
252Atk +2 Rhydon (+Atk) Earthquake vs 252HP/252Def Leftovers Cofagrigus (+Def): 62% - 73% (199 - 235 HP). Rhydon set up Swords Dance, then Cofagrigus will survive a Hit and have an opportunity to burn our dear sweeper with WoW and make it useless.
252Atk +2 Rhydon (+Atk) Earthquake vs 252HP/252Def Leftovers Dusknoir (+Def): 71% - 84% (210 - 247 HP). Dusknoir the samething of the other Ghost.
252Atk +2 Rhydon (+Atk) Stone Edge vs 252HP/252Def Leftovers Tangrowth (+Def): 54% - 64% (220 - 261 HP). Tangrowth survive one Hit and can use Giga Drain to OHKO Rhydon easily.
252Atk +2 Rhydon (+Atk) Stone Edge vs 252HP/252Def Leftovers Levitate Claydol (+Def): 38% - 45% (125 - 147 HP). Claydol survive two Hits and does 51-61% to Rhydon with Earth Power, that means it will kill our sweeper.
252Atk +2 Rhydon (+Atk) Stone Edge vs 252HP/252Def Eviolite Ferroseed (+Def): 31% - 36% (91 - 108 HP). Ferroseed survive, too. But it can't do much back tought, maybe stalling with Leech Seed + Protect or switch to any counter, I dunno.
252Atk +2 Rhydon (+Atk) Earthquake vs 252HP/252Def Leftovers Alomomola (+Def): 55% - 65% (298 - 352 HP).Alomomola will survive a Hit and can Scald Rhydon, giving 61-72% and a chance to burn with Scald or 71%-85% with Surf.
Ok, I found six ways to try Counter it just thinking really fast (maybe I can find even more Counters). We can put Megahorn instead some other move. But with Earthquake + Megahorn flying Pokémons will laugh from Rhydon face, and with Stone Edge + Megahorn I'm very afraid to have to Sweep a team using most part of the time a 80 accuracy move.
Right, and I even didn't mentioned the fact of with 252 Neutral Nature Rhydon and you BIG Speed base (ironic) reach only 179. I'll wont list everything that can revenge Kill Rhydon, just search something with decent Special Attack, an Neutral or SE move and more than 40 speed base. There are MANY Pokémons that could do it.
Then, you can say to me "I can use RP instead SD". Yes, you can, but it will won't pass a few things that can OHKO it back like Sceptile, Dugtrio or any Scarfer with more than 240 Speed Status. Additonally, Rhydon will have a big speed, but it means that it will give 1/2 of the Damage calcs that I did before, giving 2x more chance to be Countered by that Pokémons of the list.
Well, we can still try to do this team, but start to think about how to Counter everything that I mentioned and trust me, its almost all the entire RU tier. Good luck!