Brooks advertises the PureFlow as the “lightweight road warrior”, and in our testing, that proved to be an apt description. We put the PureFlow 4 through more than 100 miles of asphalt and dirt running, and it showed minimal signs of wear. Comfort is excellent throughout the shoe, and modifications to the uppers from the previous model are improvements to an already strong shoe. 

Fit

With the PureFlow 4, Brooks ditches the burrito-style tongue from previous models in favor of a traditional tongue. The lacing system holds its tension very well during the course of a long run, without need to for re-tying or adjusting the fit. An elastic Nav Band anchors to the midsole medially and laterally, wrapping over the top of the arch to hold the foot against the midsole. The vamp of the PureFlow 4 is slightly wider, accommodating a variety of feet, but its width did not feel sloppy in our testing. 

Comfort

The PureFlow 4 is slightly wider in the forefoot compared to previous versions, creating a toe box that provides full toe splay and prevents chafing. However, it still manages to be narrow enough to be quick and agile. Padding around the heel collar and ankle are just right for lightweight comfort. A number of overlays have been removed from the toe box area, improving breathability of the single-ply mesh, although the PureFlow still isn’t as breathable as others in the lightweight category. 

Stability

The outsole is comprised of interconnected oval blown rubber pods, which provide strong traction on roads. The podding design (and gaps between the pods) provides decent grip on trails and loose dirt. The heel area is rounded toward the forefoot to promote a forward foot strike and more stable landing. 

Smoothness (flexibility)

Brooks BioMoGo DNA midsole material, supplies adaptive cushioning that is softer when you’re running easy, and firmer when you’re running faster. The material worked well in our testing and provided a great combination of cushioning and responsiveness. BioMoGo is also highly flexible; the shoe flexes well from rear to forefoot, and each midsole pod can also flex and absorb impact independently of the others. 

Speed and Agility

For a moderately cushioned shoe, the PureFlow 4 is nicely lightweight, with a stable fit, responsive midsole, and sure grip on a variety of surfaces. This isn’t specifically marketed as a racing shoe, but the PureFlow 4 makes fast training sessions quite a bit more bearable. 

Responsiveness

Heeluxe, our shoe testing laboratory partner, tests the responsiveness of a shoe by measuring how thick a running shoe is and multiplying it by how much pressure the forefoot foot feels while running. The softer or thicker the midsole, the less responsive a shoe will feel, but the more comfortable the shoe will generally feel. The thinner or firmer a midsole is, the more power you’ll feel at toe-off.