A few readers have mentioned the 11’s forefoot mesh was a weak spot, so logically raising the bumper (equals more vertical space for the toe) and backing the mesh material is a reasonable solution.
The midfoot gets a few extra overlays on the outside. The fish scale type of urethane layers are replaced with sharper looking welding, and the sides get stitched-on overlays.
The Inspire 12 drops the English-Japanese logo combo of the 11, and instead displays the model name by means of horizontal, 3D welding.
The tongue and collar lining stay the same, and the tongue gets a few cosmetic upgrades, like the jewel-like Mizuno call-out near the top. Most Mizuno running shoes feature tongues with a very wide flap, and the Inspire 12 comes stitched with a similar component.
Mizuno, like Asics, doesn’t seem to be a huge fan of inner sleeves and gussets. So the tongue continues to sport a traditional design, attached only at the front.
Inside the midfoot are where meaningful changes happen. If you remember our Inspire 11 review, we had pointed out the irritating, stitched-on inner tapes on both the lateral and medial sides.
The Inspire 12 tweaks that design, and ends up removing the lateral side inner tape. On the medial (arch) side, the tape is still there, but moves further towards the rearfoot. This act of relocating the tape prevents the latter from rubbing against the foot arch.
These structural revisions lead to an upper fit change. The forefoot ceiling is higher, which puts a stop to the big-toe (potentially) straining against the mesh. The raised profile also opens up more room ahead, which makes the Inspire 12 run nearly a half size larger.
The fit around the forefoot sides go narrower due to the toe-bumper tips extending further towards the midfoot. This is more noticeable on the lateral (outer) side than medial forefoot, though.
Mizuno’s decision to remove one of the inner seam tapes and re-locate the medial-side tape towards the rear vastly improves the quality of midfoot fit.
And we don’t use the word ‘vastly’ loosely; the Inspire 12’s midfoot interior environment is far more comfortable than the Inspire 11’s.