Alphafly 4 vs Metaspeed Sky Tokyo: Big Bounce or Featherweight Speed?

The Alphafly 4 and the Metaspeed Sky Tokyo both sit near the 40 mm stack limit, and both carry a full carbon plate. The big difference is weight, and it shapes everything else.

Weight. The Metaspeed Sky Tokyo weighs about 170 g. The Alphafly 4 is about 208 g in a men's US 10. That's close to 40 g a shoe, which you notice the moment you pick them up.

Geometry. The Metaspeed has a 5 mm drop and a flatter carbon plate set close to the foot, which gives a direct, snappy toe-off. The Alphafly has an 8 mm drop, Air pods under the forefoot and a softer, bouncier landing.

Who each one suits. ASICS designs the Sky for 'stride' runners, who speed up by lengthening their stride rather than increasing cadence. If that's you, the Metaspeed feels effortless. The Alphafly is more forgiving of a stride that changes as you tire, and its extra foam protects your legs better in the last 10 km.

Stability and durability. Neither is a stability shoe. The Alphafly 4's wider platform feels more planted. The Metaspeed's light build means it wears faster, so save it for races and key sessions.

Price. The Metaspeed Sky Tokyo is about $250, roughly $30 less than the Alphafly 4.

Our verdict: efficient runners with a long stride, racing anything from 10K to the marathon, should try the Metaspeed Sky Tokyo first. It's lighter and cheaper. Runners who want more cushioning and protection over a full marathon should pick the Alphafly 4.