Adidas Adizero Boston 9 vs Adizero Boston 11
Two versions apart. Updated August 11, 2026. Specs are men's US 9.
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THE SHORT ANSWER
Two updates and 2 years separate the Adidas Adizero Boston 9 from the Adizero Boston 11. Net change: 1.2 oz heavier, 18 mm more heel stack, a drop change from 9.5 mm to 8.5 mm, a new midsole, $40 more at list. The Adizero Boston 10 is where the character changed, and that is the update Adizero Boston 9 owners notice first.
- Adidas Adizero Boston 11Sizes running outMen's at AmazonWomen's
Availability last checked Aug 11, 2026. Prices and stock change without notice.
The two updates in between
Each step has its own page with the full change list and the verdict on that update.
- Step 1Adizero Boston 9 to Adizero Boston 102021A different shoe
- Step 2Adizero Boston 10 to Adizero Boston 112022Faithful successor
Adizero Boston 9 vs Adizero Boston 11: every spec, side by side
The net of both updates. Per-update change notes stay on the step pages above, because they explain changes measured from a different starting point than this table uses.
| Spec | Adizero Boston 9 | Adizero Boston 11 |
|---|---|---|
| FIT AND WEIGHT | ||
| Weight | 8.4 oz | 9.6 oz |
| Widths | D | D |
| Upper | Dual-layer mesh with Coolever lining, snug racing fit | Thin nylon mesh with a stiff, lightly padded heel counter |
| CUSHIONING GEOMETRY | ||
| Heel stack | 21.5 mm | 39.5 mm |
| Forefoot stack | 12 mm | 31 mm |
| Drop | 9.5 mm | 8.5 mm |
| MATERIALS | ||
| Midsole | Full-length Boost (TPU) under a Lightstrike EVA topsole | Lightstrike Pro over firmer Lightstrike EVA |
| Plate | Torsion thermoplastic midfoot shank | Glass-fiber EnergyRods |
| VALUE | ||
| List price at launch | $120 | $160 |
Or buy the Adizero Boston 10 instead?
The Adizero Boston 10 is worth a look only if you want the ride it introduced, because that is the update that changed the shoe. Buying it to soften the jump does not work: you would be adapting to the same change either way, just at an older spec.
Buy the Adizero Boston 10
Sizes running outDiscontinued at retail. Amazon carries what remains, so treat an in-stock size as a closing window, and expect prices to swing.
Availability last checked Aug 11, 2026.
Questions runners ask
- Can I go straight from the Adidas Adizero Boston 9 to the Adizero Boston 11 and skip the Adizero Boston 10?
- Yes, but going Adizero Boston 9 to Adizero Boston 11 means taking one change in a single step: the Adizero Boston 10 is where the ride moved. The drop also goes 9.5 mm to 8.5 mm across the jump, so give it a week of easy running.
- How much did the weight change across these two updates?
- 1.2 oz on in total, 8.4 oz to 9.6 oz in a men's US 9. The Adizero Boston 10 took it to 10.4 oz first.
- Is the Adizero Boston 10 the better buy than either of these?
- On paper it splits them: 10.4 oz against 8.4 oz for the Adizero Boston 9 and 9.6 oz for the Adizero Boston 11, on a 39 mm heel and a $140 list price. Whether that is worth chasing depends on what the Adizero Boston 10 update actually did, which the section above works through.
- Did the Adizero Boston get taller between the Adizero Boston 9 and the Adizero Boston 11?
- Heel stack went 21.5 mm to 39.5 mm, by way of 39 mm on the Adizero Boston 10. Drop moved 9.5 mm to 8.5 mm, which is the change your calves and Achilles notice.
- Where does the Adizero Boston 11 sit in the Adizero Boston lineup now?
- Two versions on from the Adizero Boston 9, and already replaced itself: the Adizero Boston 12 arrived in 2023. If you are shopping old stock anyway, price the Adizero Boston 11 against it before deciding.