I have a vrx tj with 20' by 8.5 if l put king's low 30mm you think it will hit the wheels

it's highly likely you'll need to roll the guards and/or trim the flares. pretty sure other members have had to do that with theirs.

What size tyres have you got..?? 225s..? 225 should rub but 245s will..

Offset..?

I'm on 20x8.5" +35 and I'm running 245/30/20s

No rubbing..

SuFz

I reckon you'd need to roll the rear guards.