Concerning the differences between the Brooks Cascadia and the Adrenaline ASR, it really comes down to the type of trail running that you’re doing. The ASR is the most versatile trail shoe, working on and off the road. It’s a take down from the very popular and most successful selling shoe, the Brooks Adrenaline.
All of the fit is the same but the upper is weatherized so it’s able to stand up against high winds, rain, cold weather, and the elements. The ASR will see to it that you’re taken care of, whether it’s running on the trail or in adverse conditions. The bottom of the shoe has also been re-rubberized so it’s a more aggressive rubber configuration providing you better traction than would the Adrenaline.
For trail enthusiasts looking for a trail shoe from the ground up, every detail in the Cascadia is attended to in order to meet your needs. The outsole has bi-direction lug configuration, breaking mechanisms in the heel, propulsion in the forefoot, and a nice ballistic rock shield that sits underneath the rubber in between the mid sole, protecting the foot from any foreign projects.
The midsole has details like iconic pivot post technology, in which it really acts as a suspension for the shoe so you avoid any medial or lateral inversion ankle sprains.
The upper part of the shoe is weatherized with hydrophobic meshes foams and collar lining. Any water that gets in moves out quickly. Additionally, it is very breathable, pliable, flexible, and allows you to get up and down the trail quickly and efficiently.