Since there is no good Rumble builds on here, I thought I share Phreak's build order. It has been working out pretty good for me. This guide won't be as detail as other guides because I'm just getting used to Rumble, but this build is a good place to start. I recommend this to anybody that just wants to try Rumble. This is a pretty solid build all around. I take no credit for this build order.

This is an all around tanky build that lets you absolutely wreck in team fights. The only other tank I see doing that is probably Mordekaiser

I recommend this guide to anyone who:
1. Trying out Rumble
2. Need a more fun and unique tank
3. Don't want to feed in rank games
4. Chances of racking up 20+ kills, most of which is stolen
5. Don't want to worry about ganks

Pros:
1. Good tanking and durability
2. Good damage output for a tank
3. Can initiate in team battles
4. Great escape abilities
5. No mana

Cons:
1. Can't really farm well
2. Can't spam ability with Heats

1. Start out with Doran's Shield for some durability in lanes. After that rush to Mercury's Treads for more durability.

2. After this, grab Rylai's Crystal Scepter for some extra damage. This item is a must because the slow in combination with Flamespitter is unimaginable damage.

3. Now here you have two choices, if the other team is more Physical Damage oriented, then grab Sunfire Cape first. If the other team is more Ability Power oriented, then grab Force of Nature first. Pretty straight forward.

4. Now that you have both tanking items, go ahead and grab Rabadon's Deathcap and sell your Doran's Shield for a Void Staff to do insane damage.

Junkyard Titan: Rumble can use 5 of his abilities before it overheats, so you can do the counting.

Flamespitter: I max this out first to give me the most secure damage while in lanes. When in team fights, you always need to spam this ability and don't think twice about it.

Scrap Shield: This ability is useful for catching up to target champions or running away from them. Don't use this unless you absolutely need to.

Electro-Harpoon: You will rarely need to use this ability unless to catch up to someone. The slow output is usually not worth the heat in large team fights and you should save the heat for some other abilities. You should rarely use this.

The Equalizer: This ultimate is sweet if you can initiate a team fight where it hits 3 or more targeted champions. Once you get used to the aiming system, you can also hit a running away champs at low health since this ultimate has a nice range.

I take Ghost and Ignite if I need to catch up to low health champs and finish them.

Other notable Spells include:
Flash: A really good spell but useless on Rumble since he's not a nuke caster. Plus his Scrap Shield already provided him with an escape utility.
Exhaust: Good to catch up to champs but your Ghost and Scrap Shield is fast enough, not to mention Electro-Harpoon has a slow.

As Rumble, you have a lot of survivability so solo top would be the ideal choice. Always use Flamespitter to harass enemy champs. You can also farm with this but note that it deals half damage to minions, so only do it when minions are close to turret. Scrap Shield is to actually catch up and do damage, assuming enemy doesn't have boots of course. About to get gank? No problem. Hit as many enemies with your Equalizer to slow them down. Then escape with Scrap Shield

This is more of a risky technique but it's absolutely necessary to win games. And don't do this until you are at least level 4. Charge in with Ghost and Scrap Shield . Once they are in range, hit them with Flamespitter and Ignite to finish them off.

This is my first 5 games with Rumble and you can tell I'm getting better.
Please only criticize my guide and not my build order because like I said, this is Phreak's build order.