Adidas Adizero Adios Pro 4 vs Adidas Adizero Prime X 3 Strung:
Which to Choose

The clearest split is purpose: the Adios Pro 4 is a legal racer and the Prime X 3 is not, because the Prime X's towering platform (48mm heel / 35mm forefoot) exceeds the 40mm cap for sanctioned road races, whereas the Adios Pro 4's lower ~39mm/33mm build keeps it competition-legal. That height difference drives everything else. The Adios Pro 4 is dramatically lighter — roughly 200g in a men's US 9 versus about 291g for the Prime X 3 — a near-90g gap you feel every time you turn your legs over, which is why the Adios rates a perfect 6/6 for pace while the Prime X sits at 4/6. Drop is the other big divider: the Adios runs a low ~6.5mm offset that keeps you forward on the forefoot for quick turnover, while the Prime X's tall 13mm drop eases the heel landing and favors long-effort comfort over snappy speed. Both use carbon (EnergyRods in the Adios, a full-length plate plus Energy Rods 2.0 in the Prime X) and both feel soft-yet-lively, but the Prime X's maximum-cushion stack (6/6 vs the Adios's still-generous 5/6) is built to soak up mileage in training, while the Adios's cushioning is tuned to preserve your legs late in a race without adding bulk. Stability is a weak point for both neutral shoes, though the Prime X's trainer-width base earns a slight edge (3/6 vs 2/6) — both go tippy at easy jog speeds and only settle when you lean in and open up. In short: the Adios wants sustained race pace around 3:00–3:20/km; the Prime X wants strong, sustained uptempo efforts around 4:15/km and thrives on fast long runs, not all-out racing or short intervals.