Flexible TPU Filament - No bonding of perimeters on vase??

[EagleSeven]

Since switching to the newer aluminum gear, I've been printing perfectly with Black Ninjaflex

Curious, is the aluminum gear Larger diameter than the steel one, ?
It appears to be, but it may not be larger where the Teeth are ?
If it is larger diameter at teeth, that may explain why it works better ?

Or was the steel-tooth gear clogged with filament, making it slip ?
(I normally clean that gear after about 25 prints, to remove residue,
and Flex-filament would require it be cleaned more often)