Well... This is my secret OP. I found it to be VERY strong and I'd like to share it with everyone.

Well... What do you run on udyr? Obviously attack speed marks, armor seals, scaling CDR glyphs and movement speed quints.

I run 0/12/18 on Udyr

I rush cinterhulk, usually Poacher's Knife & Stalker's Blade. Then I get Mercury Treads then a Warmogs into a Spirit Visage. If you're almost dead in a teamfight, you'll regen back to full in 10 seconds TOPS, the regen is insane. Then I get a Dead Man's Plate and a Zz'Rot. All of the items make you incredibly fast, tanky and makes you able to split push. Situational items are Thornmail, Locket of the Iron Solari, Banshee's Veil and Titanic Hydra.

Basically, I've done this build many times and I've won at most 70% of my games with it, it's incredible of how strong it is.

Pros:
Tankiness
Split Pushing
Fast like Udyr is
Regen from Warmogs/Visage
Consistent damage from burns
Cons:
Reliant on aoe burn damage
Weak against champs with True Damage
Tower taking is weak without Zz'Rot

Your job is to be annoying with split pushing, but not with this build! Your REAL job is to peel for your carries in teamfights and/or kill their backline if you can get to them. If your team is tanky and has peel already, split push with your Zz'Rot. Early game is quite weak because you'll have 0 items and 0 damage. Mid game starts to get good, when you have Cinderhulk, Warmogs and Spirit Visage.