Not Updated For Current Season
Hi ! This is my very first build on moba, and i just want to expose my point of view with the new champ ; Rumble.
I've already tried it several games, and it seems to works very good.
I see Rumble not as a huge damage dealer, but mostly as a very effective mass-slower. This build provides him not as squishiness, but it don't make him tank or offtank.
Main purpose and early game
The main aim of that build is to really help your teammates by chasing down ennemies, or helping them by slowing pursuers ; a good aiming with harpoons saves lives, especially yours !
With 9/21 mastery and doran Shield, he can handle most damage during the early phase of the game. On end game, you'll reach up to 3k5 - 3k8 hp.
Notice that flamethrower don't deal that much to minions ( approx. 10 damage/sec at rank 1 on lvl 1 ), but it really seems to scare people and makes them not to approach.
Taking harpoons at lvl 2 is really important ; his slow is strong enough on lvl 1 to make u able to chase everything, its damages are low btw, but can provide a long-range harassment. Notice that u can use harpoons to scout brushes.
Why no meijai/occult ?
I don't personnaly reccomend snowball items on Rumble, due to the sad scaling with AP over his spells.
Snowball items are also not a stable value during your game. It's really most important to get slows and health.
Rumble has alot of ways to annoye your opponents. People will be scared, especially on early, and will fear you. Running away is a really bad, bad idea, 'cause they can't just get rid of you.
Slowing with AA
AOE Slow with flamethrower
Skillshot strong slow with harpoons
AOE Slow with ult
Target slow with exhaust
Runes, masteries and summoner spells
As masteries, I chose 9/21/0, making his less squishy, and giving him a better damage-dealing ability.
As runes, you can chose to get more movement speed as quint ( what i strongly reccomend, regarding of build purpose, giving your futher more chasing capacity, or escaping ) or hp for early game.
As summoner spells, you'll have the choice between exhaust and flash as 1st one. Regarding of Rumble's slowing abilies, flash seems to be kinda better for escaping. Ignite can help u getting kills on early, but you can replace it with teleport. Ghost is not reccomend, because of spamming speed boost from scrap shield.