Steelix @ Steelixite  
Ability: Sturdy   
EVs: 252 HP / 4 Def / 252 SpD  
Careful Nature  
- Shield Slam  
- Earthquake  
- Stealth Rock / Curse  
- Recrystalize

Other Options: EV Spreads of 252 HP / 252 Def / 4 SpD and 252 HP / 56 Def / 200 SpD, Fire Fang, Substitute with Curse