Then, and perhaps most importantly, it's the revamped upper. Brooks has used a double jacquard mesh to offer increased breathability and flexibility. Visually it's almost identical to the 17, but you can really feel the benefit of the new material when you hold it. Extremely soft and almost squishy, it feels more like a shoe designed for relaxing than one focused on performance. At faster pace, it's clear that the Glycerin isn't a shoe designed for speed. It's by no means a slow option and the cushioning does an admirable job at offering a competent level energy return, however, if you're after something for a fast time on race day, it's not one of the Glycerin 18's strengths.

I’ve never ever thought of the Glycerin as a super soft ride. It’s always been one of the firmest max-cushioned trainers. This long piece of rubber makes ride transitions smoother and also increases midfoot stability and structure because there is less flex in the midfoot.There’s nothing wrong with being a firm, max-cushioned shoe. Some runners prefer firmer shoes because they are more stable and more responsive but the problem is that the advertising for the Glycerin is misleading. This technology gives the perfect soft ride on slow jogs and a snappier feel on tempo runs. It is, of course, not universal, so a racing shoe will still trump the Glycerin during a race, but for a one-shoe kind of runner, this adaptive ride is a great choice.

The outsoles of the two shoes are very similar but the Ghost has flex grooves that run through from end to end on the forefoot. The Glycerin has flex grooves that stop halfway through the forefoot and results in a forefoot that isn’t as flexible as the forefoot of the Ghost.

Performance Comparison

This material allows supreme breathability and flexibility. With this adaptability, the shoe performs very well on almost all the runs they were put through. If you like cushioning, then you’ll like these. The Brooks Glycerin 18 is an ideal daily running shoe, perfect for easy miles and long runs. If it’s good enough for Des Linden… The Glycerin has been using the same DNA Loft midsole foam for the past 4 versions with very subtle changes in midsole foam density in each version.