One of the more common and painful things we hear at Alpenglow Sports is, “My tread is all worn down so it’s time to replace these shoes.” While that is a true statement, it unfortunately implies that this runner or hiker actually needed to replace their shoe dozens if not hundreds of miles ago, and I wait in anticipation of their subsequent explanation of the injury or pain they have experienced in these shoes. In this article, we’ll explain how the tread of a shoe is not a good indicator of the overall wear of a trail shoe and what you should look for instead. If you read nothing else, please start to replace your shoes before the tread wears flat.

Let’s get technical. A trail shoe is composed of four components that can show wear. The tread of a shoe is what we call the outsole. The outsole is composed of the durable rubber “lugs” on the bottom of the shoe and the material that holds them together. The outsole is usually glued onto the midsole. The midsole is a layer of foam that provides the cushion of the shoe. Then there's the insole, a thin, removable “footbed” between your foot and the midsole. Lastly is the upper, which is the flexible, often woven material that’s stitched to the midsole.

Eventually, all of these components will wear to the point of failure. Fortunately, you only need to focus on the midsole to make informed decisions about your footwear. This article shares tools and techniques that you can use to asses midsole wear and replace your shoes at the appropriate interval.

It’s no accident that the midsole of a trail running shoe is the first thing to fail. It’s by design! Because of this design, your shoe retains the safety of a grippy outsole and the comfort/stability of a complete upper and footbed during its useful life. The midsole fails when the foam in the shoe is no longer providing adequate cushioning. The only challenge with the midsole failing is that it is much harder to spot than the obvious tread wear and rips in the upper that we might spot first.

Midsole wear has the unfortunate consequence of accentuating your biggest issues. Imagine you have natural supination in your gait while running or walking. This results in more impact on the outside of your shoes than the inside. Over time, this will compress the foam on the outside of your shoe more than the inside. That compressed foam has less overall height and this starts to exaggerate your supination with every step. Before you know it, you are subtly slipping deeper and deeper into the outside of your shoe and deeper into a bad habit. This is how midsole wear becomes the culprit for a whole host of foot and bodily injuries. It’s a slippery slope and one that too few folks catch on time.

I’ll start with the most nuanced of our three strategies for midsole wear: You just feel it. I’m consistently amazed at the experienced runners that bring in worn-out shoes at exactly the right interval. These folks often remark that they can just “feel” that the foam is no longer protecting them. On one hand, this takes experience, but on the other it’s incredibly human. When you feel pain, excessive fatigue, or increasing intensity of rock impacts through the shoe, you know that wear has begun. If you’re loving the feel of a shoe when new, you might be able to catch when it is no longer performing at its best.

For the rest of us, we can use two visual clues to know that the midsole of a shoe is worn.

This trick comes last for a reason. While this is maybe the easiest strategy, runners can’t rely on mileage alone. Many of us are tracking mileage on each of our shoes using Strava. You can add new shoes to your Strava account and attach a pair of shoes to each run. This will reliably total the mileage that each of your shoes has endured. Generally speaking, a trail shoe should be good for 300-500 miles. Unfortunately, your mileage will vary! Some shoes are only good for 200 while some of our new super shoes will go for 1,000. You can add a mileage consideration to the above techniques which, fortunately, brings some method to the madness.

Replace your shoes early and often. Selfishly, we'd love to see your smiling faces more often at Alpenglow Sports! Not sure if it's time? Bring in your shoes and we can help you asses shoe wear and make a plan. Our experienced staff helped compile this shoe wear guide and know how to spot the warning signs. We can suggest strategies to increase the longevity of your shoes and help you find a shoe that supports your goals and your unique anatomy.