Basically you have to use vengeance after you see them cast Friction during the first spawn, it usually happens within 10 seconds of it. During the second spawn they seem to do it somewhat more randomly.

Wicked Wheel is a bit overtuned, IMO. Item level 65 tanks cannot survive double wheel without a cooldown up. On a paladin it hits for 2800 from Suparna and 3200 from Garuda. 6k damage. No item level 65 paladin has that much health. Even if they barely survive it, a single melee attack will kill them. Also, Wicked Wheel can straight up 1-shot melee dps, depending on gear.