upgrade spirit stone to spirit of the ancient golem when you feel you'll need the tenacity, getting it as your first real big item is fine becuase the health makes you beefy early on.
get frozen fist next
you're really lacking in mres at this point so get something that builds out of negatron (except banshee's veil, no a great item atm imo).
warmog's is good too.
You basically build full tank because you want to be a damage soak and peel for your team. Udyr can't really initiate this meta. Flash Bear Stun is okay. Shurelia's Bear Stance can work sometimes from sheer ms but usually you'll get kited.
Just aim to absorb as many CCs as you can while tanking damage and stunning important targets. --- ~GameFAQs LoL Board President~ http://i.imgur.com/6rO0g.png
Alternatively to g-cube's build, you can get Wriggle's + Merc Treads for a more balanced approach to damage mitigation before getting Warmog's and Randuin's and Iceborn Gauntlet and Banshee's Veil and stuff. Bonus points for Tiger Stance Wriggle's procs on Baron if/when that ever comes into play.
As he said, you're better off being a damage soak these days, because at least then you can survive long enough to stun people and be a factor. --- Miami Heat: 2012 NBA Champions | Other Miami Sports: LOL I'm a TWSSted bastard.
Triforce was only core on top-lane Udyr, and there are better options than it now. --- If you believe in Jesus Christ, have accepted Him as your Lord and Savior, and are 100% proud of it, put this in your sig. g-cube's Vice President of Cakes.