Golder Goldeater:
If I give a Bull Centaur Taur’ Ruk blackshard armor, an enchated shield,
will his armor save of 2+ combine with his scaly skin 5+ save
to give him a 0+ armor save?
rpitts2004:
Yes I would agree with this
Thommy H:
An armour save can never be better than 1+.
Golder Goldeater:
Really? Because I remember rumours of chaos lords on juggernaughts having a -1 + armor save 
I hope you are right, because that would be too cheesy! Almost as much as the 3+ ward save 
deadlydeceiver:
That was possible in the previous edition, even -2 or -3 ^^.
But now armour saves are capped at 1+, as Thommy said.
DD
Golder Goldeater:
Good news!
GW should have made a similar thing to forbid this stupid better-than-4±ward-saves.