I agree with Nine. I would change the locket to Banshee's Veil. That will give you the same amount of health and mana, but will protect you like tanks should be. You get s description and I think I found my Udyr Tank build

No description No +1

alright a few things. DESCRIPTION IS NEEDED. I have seen so many great builds ruined because of a lack of description.

Secondly, it is an interesting take on udyr, but In. Locket is no longer required for udyr, as it has been nerfed, and it is very easy to conserve mana with turtle. at lv 18, the mana isnt even relevant because 35 mana per stance is a small amount and your mana pool easily covers the bill for even the longest of team fights.

Summoner skills: Teleport, at first, seemed like a stupid skill, but analyzing it, it can make for a great udyr BD, with his tiger stance. good choice. Instead of ignite however, i suggest going ghost. it works great with his bear stance, and makes him nearly impossible to catch unless they have multiple spam slows and snares. Ignite isnt really an issue for udyr after he gets madred's anyways.

Item build: You REALLY want those shoes earlier. Because you are going tank/dps, aka offtank, i suggest starting with defensive items. Rush a Heart of gold, followed by Merc treads. that gives Udyr some balanced defense, and makes him significantly less squishy in early game. THEN you can build madred's if you so choose. I personally go full tank before building madred's, because tank udyr is more viable than dps udyr, and offtank is secondary priority for Udyr in games. That is why udyr is such a late game character. he pwns face late game with randuin's, banshee's, and madred's. From there you can get whatever you wannt on Udyr.

As for the masteries...
I STRONGLY suggest going 0/21/9. Havoc [the last point in offensive] is based off of your BASE damage, so it really only adds about 7 or 8 damage at level 18. in my opinion, not worth it. you really only need the attack speed, and nothing else in offensive if you go that route. the last point in defense decreases all damage taken by 4%. That is a ridiculous amount, and can really change the game for you. Which is whhy i take that. Now, Udyr is typically a jungle, so the 9 points in utility is required for any good jungle udyr because of the extension of buff durations and the exp boost. because you are not a jungle udyr, i would suggest going 8/21/1 focusing on attack speed in offensive, and getting improved ghost in utility, assuming you use ghost. Hope i helped! Make a good description and i will love this guide!