Start contact on yellow heat and usually trade with E1 -> W -> Q -> walk with them -> E2, because Rumble's damage gets much cleaner when Danger Zone and overheat autos arrive after you already have Harpoon stick or W movement, not before
Place Equalizer across the retreat line or choke, often a little behind the commit, so the enemy has to keep standing in the fire to leave or finish the play; dropping it directly on their current feet is usually the weaker cast
Rumble top is at his best when one strong lane turn scars the tower and then carries him into Grubs, Herald, or river fights, while long side-lane duty is where his lead and his kit both lose shape
Group earlier than you would on most top laners. If Grubs, Herald, dragon, or a river fight is coming soon, your job is usually to push one more wave, take whatever tower damage is free, and leave before the side lane gets long enough to trap you. When ahead, that often means crash and move while the wave is still forcing an answer. When behind, leave even sooner and stop trying to prove the side lane is still yours. Rumble gets paid when teams have to cross shared ground, not when he keeps extending a quiet lane with no clean exit.
Every spell Rumble casts gives him Heat. When he reaches 50% Heat he reaches Danger Zone, granting all his basic abilities bonus effects. When he reaches 100% Heat, he starts Overheating, gaining bonus Attack Speed and granting his basic attacks bonus damage, but making him unable to cast spells for a few seconds.
Rumble torches opponents in front of him, dealing magic damage in a cone for 3 seconds. While in Danger Zone this damage is increased.
Rumble pulls up a shield, protecting him from damage and granting him a quick burst of speed. While in Danger Zone, the shield strength and speed bonus is increased.
Rumble launches a harpoon, electrocuting his target with magic damage, slowing their Move Speed, and reducing their Magic Resist. Rumble can carry 2 harpoons at a time. While in Danger Zone the damage and slow percentage is increased.
Rumble fires off a group of rockets, creating a wall of flames that damages and slows enemies.