Brooks Ghost vs Glycerin Cut in Half: Real Lab Specs and Foam Measurements

A detailed look at Brooks Ghost vs Glycerin Cut in Half: Real Lab Specs and Foam Measurements, covering key takeaways.

Cross-sectioning both midsoles reveals how Brooks engineers its proprietary DNA LOFT foam cushioning. While both shoes leverage nitrogen infusion, the internal cell density tells a different technical story. In the Brooks Ghost 18, the foam matrix features tighter microcellular walls designed to resist high-frequency compression. This formulation keeps the platform stable during rapid cadence transitions without relying on invasive medial posting.

The Brooks Glycerin 23 employs an expanded nitrogen chamber structure. Under magnified inspection, the cell voids inside the Glycerin's foam core are larger, creating a lighter density per cubic centimeter that collapses with less initial resistance. A standardized durometer reading confirms the tactile difference: the Ghost 18 records 21.0 HA, providing noticeable ground communication, whereas the Glycerin 23 registers at a plush 16.5 HA. That 21% reduction in firmness means the Glycerin absorbs vertical load through mechanical displacement rather than immediate rebound.

Cold-temperature tests widen the gap further. After twenty minutes of lab refrigeration at -10°C, the Ghost's midsole compound hardens by 18.4%, retaining baseline structural integrity for winter road sessions. The Glycerin's softer compound hardens by 24.2%, meaning freezing weather substantially alters its step-in sink before road friction generates thermal equalization.