I play a lot Lee Sin, unfortunately every single time I face a Rumble at top I lose to him. So I was wondering, what can I do to beat Rumble?
I dont know how long you already play Lee Sin, or how recently you faced these Rumbles, but since Riot tried to make his Flamespitter more responsible (2Patches ago) it is OP. Before the Patch, the Flamespitter would hardly ever hit and therefore they gave him more dmg, but now, it always hits, and it does INSANE dmg. Its like really broken now.
So if you are only loosing to Rumble the past couple of weeks, you should just wait after the next patch, cause Riot already announced an nerf to his dmg. If you had problems before too, here are some general rules when playing against Rumble: