Your role is to poke and provide peel for your carries. One of the biggest faults I see in Rumble supports is not maximizing their teams late game team fight potential. Even with a small budget Rumble can do serious damage and that can go to players heads. Think of yourself as Braum. You should not be on the front line necessarily but in the middle of the group ready to throw out poke and turn around to delete any would be divers onto your carry. you can maximize the amount of damage they do by having them take advantage of your MR shred/damage amp while simotaniously making it difficult to get to them or hit with long range projectiles.

By using your you can speed in and poke with and get out awhile mitigating any return poke you might have recieved. The slow applied by the harpoons makes it impossible to avoid your arcane comet rune. In some cases when the return poke is high enough, I may suggesting putting a second point into shield before maxing last. When it is time to fight, activate -> apply damage, slow, and MR shred with 1-2 -> use to (overheat) -> melee to death

Remember, does not generate any heat so you can use it at any time in your combo as long as it is before you overheat. How you choose to lay it down is extreamly situational but mastery of it can completely change the outcomes of entire teamfights and securing/stealing objecives! Some examples can be to apply it down the middle of group to force team to split, off center to cut off retreat paths or make them group up, or traping them inside tight places in the jungle or pits.

In lane (While poking out enemy) you want to stay just below or hover around 50% heat. This will afford you plenty of options if you get ganked and surprise them with underestimating your damage output when you enter the danger zone and savage attacks when overheating

Lane Phase

Risk of Ganks become exponential higher after the 3:45 mark so be aware of the time.

When you do go recall, if your lane is pushed out or you believe bottom can farm safely try and look for an oppertunity to assist jungle in taking voidgrub, Rift Herald, or Dragon followed by gank top or mid but then get back to lane.

Lane phase is nearly over, you have completed your first item and teamfights on objectives are more likely. Your usefullness in teamfights is directly tied to your ability to control your heat. For this reason proper vision is imperative. The more information you have on the whereabouts of the enemy the more time you have to prepair your heat level for a fight. Season 16 with its buffed vison locations has greatly helped rumble manage this.

Mid Game

After Tower has been taken you and Bot should have the goal of rotating mid then top and taking both of their outer turrets. The only time you should be alone is if you are traveling/placing wards. Your focus is purely on assisting team in taking objectives. This is because with Bloodletter's Curse and Electro-Harpoon you should be absoloutly shredding enemy MR by amping up your teams damage.

Late game tips

+ DON"T FORGET to always drop a ward near/in enemy base so your top lane can backdoor teleport to!

+ assist team in pushing minion waves by activating Flamespitter and walking straight through the wave. Your burn from Liandry's Torment or Fated Ashes will drop them low enough for them to sweep the wave.