A few typos here in there, but overall I like it. Heck you may even want to take a look at mine.

By the way, Madred's Bloodrazor is very worth it on Udyr. It's one of those items that lets Udyr buy wards because he doesn't need any more items. In my experience, Wriggles+Merc Treads+Bloodrazor is enough to tide you over into the late game. Don't ignore that fact.

K so ive looked it over and im gonna need to update it a little more, but ive taken out Bloodrazors and thornmail even though depending on the dps/magic build of the opposing team you will either want Thornmail or Banshees Veil but Force of nature seems like it has a more fitting place than Bloodrazors for a Tank build. Atmas should be enough given how much his abilities increase his damage.

I also have the filling that he dont survive tanking with only 77m resist.

I believe your thinking of....Force of nature maybe? im not quite sure either, thanks for the suggestions.

I dont think that bloodrazor is needed. Magic resist makes it almost useless. I would say either Bloodthirster because with lifesteal you are unkillable in turtle form or some sort of magic resist maybe the MR movement speed health per second (the item name escapes me atm). Overall good guide.