Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
Rumble - The Mechanized Menace
Rumble is more of a beefy caster DPS that isn't afraid to tower dive or initiate team fights. With proper use of Scrap Shield and the assistance of your fellow teammates you should come out victorious with minimal - no deaths. Before you rate this build, please do more than ten games with the hero as he is a difficult one to learn.
From experience, Rumble is primarily dependent upon how well he does in the beginning of the game as he is very item dependent. There for you will want to start immediately with straight AP marks, quintessences, and glyphs. For seals you should use the fortitude as the initial 48 HP can come in VERY handy staying in the lanes. I suppose that CDR runes might help, but because of the fact that Rumble's cool downs are already considerably low you are better off with flat AP. While Rumble can go in and melee for decent damage, he is under no circumstances a crit reliant hero, therefore you should steer clear of the crit chance and damage runes.
UNDER NO CIRCUMSTANCES SHOULD YOU EVER GET MANA/Mp5 RUNES. If you do, search for the "Uninstall.exe" file as it will improve your skills exponentially.
The standard build for a Rumble at the moment would be 9/21/0. This is due to that fact that like all other casters, the 15% MR reduction is a requirement. The 21 points are put into defense instead of utility due to the fact that Rumble is not CRD reliant. He is far better off taking less damage to allow for the max amount of ticks off Flamespitter.
In my experience you will want to start off with the Ability Tome + a health potion. The Ability Tome is to help secure a first blood, something Rumble is very successful at getting. In case things go bad on the initial fight however, you have a health potion to spare. After your first B you should purchase the rank 1 boots and if you have enough money a blasting wand too. After the blasting wand purchase you should have a good idea if the enemy team is going to be a heavy MR team. If they are, you should purchase the Sorc's boots. If not you should purchase the Lucid Boots (the 15% CDR is plenty enough for the entire game). Your next big purchase item should be the Deathcap, followed by the Void Staff. However if you are dying too much while attempting to get your Deathcap you should get the Hourglass first. Your final purchase is up to you, however if you are getting this far into the build you are most likely fed. Being so many kills ahead of anyone on the enemy team I get a little cocky therefor it is nice to have the rez from the Guardian Angel.
When entering any fight you should cast Scrap Shield as it allows for you to move faster into the heat of battle before the shock and awe of a Flaming Yordle hits and they have time to react. When close enough cast Flamespitter, sit back, and watch their health drop faster then Cho'Gath nomming a Veigar. If the battle is 2+ people, open with The Equalizer, pointing it in the way you'd expect them to run. Now comes the funny part... Watching people attempt to run. Pop off 2 Electro-Harpoons into their back while chasing them down with Flamespitter. Be sure to cast Scrap Shield at every opportunity as it shields you and allows you to keep up with your prey. If needed, pop ghost and feel their rage through the monitor. Use ignite if you are worried if that Yi is going to get away.
Ignite - GET IT - USE IT - LEARN TO LOVE IT. My favorite summoner to have on Rumble, and I laugh at any Rumble on the enemy team that I see that doesn't have it.
Ghost - My second choice as it helps when they are outrunning my Flamespitter and Scrap Shield.
The only other viable summoner would be Flash.
If you play Rumble correctly, you should have no problems achieving ratios like this. Keep in mind that he is a hard hero to learn but a rewarding, and incredibly entertaining, hero to play.
This guide was released on day one of Rumble and written rather poorly, but I wanted to get it out there to give others a chance to see what item/skill order to use.
It will be updated.
Please post any CONSTRUCTIVE criticism.