Salomon Aero Blaze 2 vs Salomon Aero Blaze 4:
Which to Choose

Both shoes share a neutral platform, no plate, and an 8mm drop, and both run to Salomon's characteristically snug, low-volume fit that wide-footed runners should approach carefully. The core difference is the midsole. The Blaze 2 uses Energy Surge EVA, a single-density foam that reads firm, lively, and connected — you get honest ground feel and a peppy return at tempo, but at slow paces it can feel a touch flat, and it never turns plush. The Blaze 4 swaps in optiFOAM² beaded TPU, a bouncier, more resilient material that stays soft-but-firm: there's more genuine spring when you lean into it and more composure over long efforts, without going mushy. That's backed by the geometry — the Blaze 4 sits on a 36mm heel / 28mm forefoot stack versus roughly 32mm / 24mm on the Blaze 2, so it adds about 4mm of foam front and back. Crucially, it does that without gaining weight: the Blaze 4 comes in around 226g in men's US 9, essentially the same as the Blaze 2's ~230g (8.1 oz), so you get more cushion for free. The extra material also shifts the useful range — the Blaze 2 is happiest from 5K to the half with the 10K as its sweet spot, while the Blaze 4 reaches from the 10K out to the marathon and settles into the half as its natural home. The 4 also brings an all-new engineered mesh upper with 5D print overlays for lockdown and breathability. Both are honest, moderately cushioned neutral trainers, but the 4 is the more cushioned, bouncier, longer-legged of the two, and the 2 is the firmer, more ground-connected one.