Yea really not much I have to say about this build besides it works for me a lot better than anything else I've tried as Rumble. As long as you watch you're positioning in lane and all the other standard stuff you should be pretty well off since it spreads out all the bonuses of your build pretty nicely. You get early armor and AP to start and some bonus durability cause rumble uses no mana and you have 5 hp pots, you get max CDR pretty fast so snowballing will be ez with the constant ult-> harpoon-> flame combo, and you get magic pen and lots of hp, and that's all before you finish a single item. Basically I just make my top opponent push me with some harass then ult when he's far enough away from the turret, even if you don't get a kill you can get some cs or gank after this since they'll probably B. So this build all around makes it hard to fall behind and easy to catch up since theres a ton of cheap 1k items that will help alot, and late game you have around 4k hp, 150 armor, a super sweet gap closer and 2 other active effects, and super high dps and CC.