Board Thread:Naruto Discussions/@comment-5413572-20140703171400/@comment-1512913-20140703220322

Again, none of the Tailed Beasts have Sharingan, Rinnegan or any doujutsu for that matter, neither does Gedo Mazo, only when the two are together as Ten-Tails/Kaguya.

Madara had Indra and Ashura's chakras, therefore Hagoromo's, who has half of Kaguya's. So even half of her overall chakra is enough for Rinnegan, but remember the chakra was split into many aspects, unfortunately the doujutsu is hidden in both chakras of the Tailed Beasts and Gedo Mazo.

So it's not even about how many % of the chakra Naruto has, but if he has the right part of it, which he doesn't.