Rumble, yes the yordle with the machine. A dps, burst, nuke champion that sometimes are mistakenly used as a Tank. This time, I'll be taking you to a Rumble upgrade. From a sadistic support, harasser to a surprisingly rapid build nuker to the team.

Rumble has a good skill set to be played as a top, as a mid and as a jungler. Well most of the champions, especially mages, can also be used as a support, Rumble is considered a mage/fighter so he is not an exception to be a support. His Flamespitter and Harpoons can blast bot lanes to hug their tower early in the game. Of course as a support you'll give the kills to your adc and take all that assists but don't blame me if you get 10/4/16 because of this build.

Pros:
High Magic Damage
Early game harassment
No mana, no issues
Good in Team fights
Above Average Health
No need for above 300 AP to deal threatening damage
High Casting Range of Ultimate
High pushing power
Fast gold generation


Cons:
A fake Tank
Need to be near to enemies to deal damage using Flamespitter
A not so reliant Scrappy Shield (don't rely on it)
Can get kills faster than his ADC
No disable
Can easily be focused
Overheat sucks sometimes.. ;)

Flash - ANY GAMES, take flash. You need this for your escape and initiation. Don't hesitate to take it because if you do, you'll search for it.
Exhaust - As a support, you need an additional slow for you to protect yourself and your adc.
Ignite - As a sadistic or aggressive support, if you want kills for yourself or cast a grievous wounds on target for them to reduce regeneration, then this spell is for you.
Teleport - A conditional spell if you're going to assist your team globally. This can be helpful on the late game if you're going to split push using your Zz'Rot Portal.
Heal - As a support, you'll be able to heal your ADC and get a slight boost in movement speed, a nice to have spell but still will prefer Exhaust.
Barrier - Honestly, Barrier has been overpowered by Heal due to it's low health block, a waste of spell slot.
Ghost - Ghost is essential good but not for this Champion. You already have slows in your skills and item build, you won't even have to boost movement speed more because you already have your Scrappy Shield. This spell is a waste.
Cleanse - Cleanse is good if you need disrupt team fights. Use this if you HAVE to but don't take it. Promise you won't need it.
Smite - For a Jungler ofcourse, but for a support?? There are more spells better than this.
Clairvoyance - This spell is good but it is taken by the Farsight Trinket.

Starting Items:
Take Relic Shield and 3 Health Potions - 500g
This will grant you a gold sharing execution for you and your ADC. 3 Health Potions is enough to sustain you in your lane. While you're at it, save your money to 1225g before you go back to your base.

First Back:
Upgrade Relic Shield to Targon's Brace
Take Sightstone, bring Vision Wards and change your trinket to Sweeping Lens - 1225g
Yes I know, it is 25g away to Needlessly Rod but it is too early for that. 1225g for support items supposed to be between 4-7 minute mark (well that's pretty slow). Targon's Brace for more health and more executions with less cooldown. Sightstone for warding and Vision Ward for your sight to stealths. Sweeping Lens for dewarding. This will be enough for you to save 1550g for your next return to base. This will be probably at 10-12 minute mark and by this time you are supposed to be at level 6-8 and have taken the first Dragon.

#1 Upgrade:
Take Needlessly Rod and Boots of Speed - 1550g
Now you've got a Sightstone and a Targon's Brace, you'll save up to 1550g and buy this item for a little upgrade to your skills. You're working now as a support and you're effectiveness in the whole team is functional. This purchase order will be your next step for skill upgrade. By this time it is 10-12 minutes and your level maybe from 7-9. Taking the next dragon is the next objective and additional high AP for the next team fight is necessary. Mobility on the other hand can boost your escape and initiation. Next save up to 1600g (that's so expensive and it takes you 4 kills to get that.) to buy the next item.

#2 Upgrade:
Take Haunting Guise - 1600g
Yes, I know you're spending so much and saving so much money. But for a support, money is not a problem and you can generate that gold in no time. by 14-16 minute mark, you may probably have this item if you're following this guide. Take this item for additional magic damage, health and magic penetration

#3 Upgrade:
Build Rylai's Crystal Scepter and Sorcerer Shoes - 2750g
This time is going for the core item build which will cost you so much. Start with the Sorcerer Shoes(800g), Giant's Belt(1000g) then build Rylai's Crystal Scepter(950g). I know it's too much but whenever you buy these items accordingly, you'll see improvements to your Rumble that makes these items his core build. 25-30 minute mark you'll able to achieve this core build.

Core Items:
Targon's Brace
Sightstone
Sorcerer Shoes
Rylai's Crystal Scepter
Haunting Guise
Vision Wards
Sweeping Lens
These are the core items of this build. You've got your gold item, your source of wards and a vision ward, mobility with magic penetration, ap item with health and slow ability and an ap item with more health and magic penetration. These are all you need as a Rumble. Whenever you achieve this build in more than 30 minute mark, then you'll probably won't achieve the Rank S Mastery on that game. Follow this guide and you'll enjoy Rumble as a support.

Full Support Upgrade
As a full support Rumble, you may want to upgrade your Targon's Brace to Face of the Mountain for more health, gold and shield for you ADC. Upgrading your Sightstone to a Ruby Sightstone will improve your source of warding and gives you more health with an item cooldown reduction. Rushing Zz'Rot Portal after your core build will build you armor and magic resist with the reward of defending/pushing your lane. Locket of Iron Solari for boosting defensive plays in team fights makes you a valuable teammate in the game.
This build won't focus on any damage on Rumble and you may want to sell your Haunting Guise and change your Sorcerer Shoes to a different shoes later on the game but DO NOT remove Rylai's Crystal Scepter.

Full Mage Upgrade
As you upgrade your Rumble into a Mage, you may want to upgrade first your Haunting Guise into a Liandry's Torment to improve your health, ability power and magic penetration. Then build something according to what will be the enemy team's composition. Build Abyssal Scepter if the enemy team have more magic damage. Build Void Staff if your enemy team have a massive magic resistance. Build Zhonya's Hourglass for certain situations when you realize you need it in team fights. Build Hextech Protobelt-01 for more mobility, more health and more ability power. And lastly, build Rabadon's Deathcap if you feel you need more damage and more ability power above the 300 mark. This is item actually unnecessary most of the games so don't bother buying it.

Survivability
As you know Rumble is typically a Mage/Fighter champion that can deal more damage when using his Flamespitter. But while at it, Rumble is a fake tank. He got a chunk of HP due to Rylai's and Haunting Guise but it does not change the fact that he is not a tank. By doing this upgrade, we cannot still be able to say that he is now a tank but we can say that he can survive more while giving enough damage to enemies.
Building Randuin's Omen to slow ADC of their attack speed and cast the slow when enemies try to focus on you. Still Randuin's Omen gives you a lot of health and armor and may consider to buy it if the team have more Attack Damage.
Building Warmog's Armor for me is quite necessary. Due to Rumble having no mana but have better cooldowns, he lack on health sustain. Buying this item may compensate to where he is lacking. Boosting your health to 800 and giving you a burst health regeneration while out of combat may Rumble won't go home anymore.
Building Banshee's Veil counters any magic abilities. 70 magic resist and 300 health is a big deal for Rumble. Mage assassins like LeBlanc and Akali won't be able to burst you anymore and you can still place your threatening skills on the field.

"Follow this guide and you'll enjoy Rumble as a support."

Take Harpoon at level 1.
Taking Electro-Harpoon at level 1 may give you distance from your enemies while executing minions using Relic Shield. Denying them on minion's experience by zoning them using Harpoons will draw them near to their tower. Your Flat AP Runes will give this skill an itching damage at level 1. This skill also helps while invading jungles and level 1 team fights because of its impaired slows.

Max Flamespitter first.
This will be your bread and butter. Your main DPS and your value to the team. Flamespitter will be your main damage output and it's sick damage with the slow effect of Rylai's will make your enemy champions cry out of damage. Adding with Liandry's Torment and Thunderlord's Decree will make this skill untouchable.

Take Scrap Shield at level 4.
Why not take Scrap Shield at level 3 after leveling Flamespitter? At this point of the game, you may not want to engage in team fights in level 3. So after I've realized something, early levels of Flamespitter is sick to enemy champions. Contradicting? No to team fights at level 3 but get Flamespitter level 2 for better damage? When the enemy team tries to engage, you have an advantage to fight because of your better damage. Taking level 1 of Scrappy Shield on early levels will not give you any benefit and it will just waste your skill for low level. Yes, taking Scrap Shield for the Overheat can be more useful but staying on the Danger Zone while blasting your Harpoons is enough to take you on Overheat in team fight on level 3.

Take Equalizer every time it is available
Well this is obvious. Equalizer is and underrated ultimate. It has a decent amount of damage, slow, high casting range and decent cool down. This will be your key. Correct positioning and placing of this will make your enemies change their target on you.

There are many ways to build Rumble:
Full DPS Mage
Full Burst Mage
Mage Tank
Mage Support
Support Tank
Full Support
DPS Mage Tank



But in this build, we'll take the 0-18-12 masteries.
Cunning
Wanderer - Take this for more mobility out of combat. Going from base to your lane, catching up to your ADC's, supporting your jungler in his objectives and warding/dewarding.
Secret Stash - For more health sustain in lane for you to accomplish the item set guide which will require you to save gold in time.
Merciless - Burning your opponents may not be enough to kill them but taking this mastery will boost your killing potential. And also Meditation will have no effect on Rumble because he does not have any mana.
Bandit - As a support, you need gold generation and attacking champions grants you 15 gold and when minion dies you gain 1 gold. You'll achieve your item sets in no time.
Intelligence/Precision - Actually I'm not a fan of Precision but I may consider it due to it's penetrations. Additional 5% cool down reduction at level 1 is great for reducing the cooldown of Flamespitter and Harpoons. At 45% cool down reduction, your Equalizer will just only have 49.5 seconds from 90 seconds which is awesome!
Thunderlord's Decree - Best keystone ever... Do I have to explain?


Resolve
Recovery - For more health sustain and Unyielding sucks.
Explorer - Additional movement speed in brushes and river while Flamespitting. Imagine that.
Veteran's Scars - Additional 50 Health at level 1 plus 75 Health on Relic Shield, that's 125 Bonus Health at level 1.
Insight - Cool down reduction of Summoner Spells is not a bad idea compare to the burst of health regeneration which will base on your own health regeneration which is low. Nah..