Well sorry for doubble post !
But ive worked out a set that beats every none steel type in the tier under a sub, this set OHKO's or 2HKO's ALL pokemon in OU bar steel types. Also it 3HKO's ALL steel types in OU.
Also you might get surprised Ferrothorn and Skarmory cant wall this set both gets 2HKO'd, not even max Def Skarm can wall it.
Kyurem-B @ Icicle Plate
EVs: 184 HP | 252 Atk | 72 Spd
Adamant Nature (+Atk, -SAtk)
Substitute | Freeze Shock | Fusion Bolt | Roost
This set is awesome, so first off ill explain the EVs. 72 Spd lets Kyu-B outspeed all base 61 Spd pokemon this means that this Kyu can beat Jolly Tyranitar while beeing under a Sub, this spread also lets Kyu outspeed 16 Spd Tentacruel, Standard Jirachi/Celebi, bulky Rotom-W and speed ties with Gliscor which doesnt matter as Freeze Shock OHKO's it anyway, 252 Atk to hit as hard as possible, and Freeze Shock is just ridicoulus doing around 50% to wall Jellicent, the rest put in HP for maximizing bulk and with this spread Kyurem's substitutes gets incredibly bulky. Also with Freeze Shock + Fusion Bolt Kyu gets the best coverage it can get withouth getting stucked to Outrage or minimize its speed or defenses with Earth Power, Roost is for regaining HP so it can be around for a longer time and set up subs more often, as Kuy's sub is so bulky it can afford to run a Icicle plate which let Freeze Shock have a BP off 252 STAB attack, which is pretty much insane due to its already massive Attack stat.
How I actually came up with this set was actually because off SubPunch, this works just about the same and with all the switches Kyu-B forces it can easy set up a sub and fire off. Also a thing I noticed this guy totally needs EQ, with EQ this set would have been so insanely strong with nearly no counters at all.
EDIT: Leftovers are also viable as this lets your longivety increase in Sand, but Dugtrio can easely fix this as its an excellent partner and Kyurem-B beats Tyranitar under sub anyway, just for the people like beeing safe and really dont feel that roosting all to much will fit them.
So what do you guys think off this set ?