What makes your more tankier? More health stats or more armor / mr stats?

Both. Having one without the other will still handicap the idea of being tanky.

You need to calculate it. Let's say you have 100 armor -- building a chain vest will cost you 800 gold and give you an extra 40 armor. If you have 2000 health this means your effective health AGAINST AD DAMAGE ONLY will go from 4000 health to 4800. By comparison 2 ruby crystals for the same price give you extra health which becomes 600 effective health with 100 armor. In this instance taking the armor is better if they are only physical damage.

Now to compare a 2000 health champion with 200 armor building it will go from 6000 effective health to 6800 health. That's still the same but the two ruby crystals will take you from 6000 health to 6900. In this case health becomes more effective.

The other thing to keep in mind is what the enemy is building/type of damage. Armor and magic resist only works against one type of damage and can be affected by armor and magic penetration. On the other hand health works against both and only loses to % health damage.

As a general rule of thumb though; you want to build both and thankfully most defensive items whether they be armor or magic resist; will provide you with both.

Yes

You definitely need both, which is why its kinda painful to build tanky on champs like and because their low base hp means that their HP pool will never be THAT high.

Do the math.

Just calculate your effective hp. Let's say you have 2000 hp and 50% damage reduction then you have 4000 effective hp.

If you add another 500 health, you now have 5000 effective hp.

If you instead add more armor and bring yourself to 60% damage reduction you now have 5000 effective hp.

In that example both cases are the same result and you'll last just as long against pure physical damage either way.

Thanks guys. Ive been testing a lot lately specifically udyr. I wasn't sure if I have been going to much armor and mr and not enough health and vice versa. I tend to die a lot in the front line because I get melted pretty easily. I understand he's an offtank but still I feel like I could withstand a bit more dmg if i built properly

Look at it based on complete items. will help you survive against crit based champions. is good when you are the primary engage against a team that is at all dependent on attack speed. is great if you need to get into the fight to disrupt but keeps peeling you off before you can do anything.

The objective of tank itemization is to get you to the center of the fight to get the most effect out of your abilities. is great against teams with magic damage when you have some sort of sustain in your kit, like Zac, Voli, Mundo, even some bruisers like Darius. , though typically a bruiser item, is great if you need more momentum in your engages or to force good fights by making catches. is great for more dueling/splitpushing power, or just generally if you suspect to have sustained fights or sticking power.

it all depends on the incoming damage like if al enemies are ad then you want armor and hp but if they deal a great deal of mixed damage I guess see where it comes from. like if their ap damage is from an under fed ap mid and a support then you can get some mr but you want to get more armor since most of their damage will be form top adc and jng

or if their ad damage is lacking and their adc maxes speed over damage and mid is on fire with a lot of ap then you want to get more mr than armor.

your build should essentially reflect where and how you get damaged in the game good tanks from what I see usually start to get these at the beginning and then once they have a grasp on incoming damage they rush what is needed to stay alive longer.

(just what i've seen spectating plat and above games)

Early game you want health. late game you need both.