KEEN No break-in time review

The No break-in time is an iconic low-cut day hiker from KEEN that we recommend as a great choice for: 

• Casual hikers looking for a lightweight and comfortable shoe that can be used both for light hiking as well as everyday activities
• Track and XC
• Anyone in the market for a breathable waterproof shoe that will ensure a comfortable and dry hiking experience
• Hikers who frequently go on winter treks and need a shoe that performs consistently in cold conditions

Hikers with narrow feet will likely find themselves bumping against the walls of the No break-in time, especially during descents. For a shoe with a more snug toebox, we suggest checking out the Midsole softness soft to firm.

While the No break-in time is relatively breathable for a waterproof shoe, it's going to feel quite stuffy during hot summer hikes. The Both sides full is a more well-ventilated option that won't turn into a sweatbox as the mercury rises. 

If deep puddles and river crossings are part of the planned adventure route, we recommend opting for the shoe's mid-length cousin; the No break-in time Mid instead.

We don't expect much airflow from a waterproof shoe, though the No break-in time surprised us during our smoke test with a slow but relatively steady stream of smoke making its way through the tongue. We wouldn't exactly describe it as airy, but the No break-in time performs better than anticipated, earning a breathability score of 2 out of 5. As a result, the shoe will certainly feel quite toasty during warm hikes, but not nearly as bad as some of its other waterproof counterparts. Conversely, this makes the No break-in time a great companion for those challenging and frigid wintertime adventures. 

Compare that to how easily the Both sides full vents out the smoke, making it better suited for summertime hikes. 

The No break-in time entirely blocks out the light when inspecting a backlit cross-section of its upper, confirming the shoe's insular and watertight nature. With the shoe being a low-top, however, we recommend avoiding splashing through streams as any water that does manage to get in through the top won't drain out. We recommend checking out the shoe's mid-length cousin, the No break-in time Mid for treks where being submerged in water is a possibility. 

As we saw in the smoke test, the tongue is the only part of the shoe that promotes any airflow. To investigate this further, we looked at it under the microscope and found that the mesh is incredibly dense and compact enough to prevent water from seeping through.

First up to face the Dremel in our battery of durability tests is the No break-in time's toebox. Spinning at 5K RPM, we pressed the tool's abrasive element against the shoe's reinforced toe bumper. 

After twelve seconds of grinding, our Dremel wasn't able to wear away enough material to reach the leather part of the upper, with only a barely noticeable scuff left in its wake. This confirms the shoe's tank-like build and means that our feet are well protected from any knocks or bumps along the way. 

Now focusing on another vulnerable part of the shoe, we set the Dremel against the No break-in time's heel collar for four seconds. 

The damage is hard to assess visually, but there is a notable crater where the tool's abrasive element made contact with the shoe. The damage isn't too devastating however leading us to give the No break-in time a heel padding durability score of 3 out of 5. 

Pressing our durometer against the outsole gives us a reading of 82.1 HC. This is on par with our current lab average and doesn't give us too much cause for concern regarding its durability. Our confidence in the outsole will be put to the test in the next section. 

Last to face the merciless Dremel is the outsole. Now spinning at a more formidable 10K RPM, we set the tool against one of the No break-in time's lugs. 

After twenty seconds of debris misting our workstation, we assessed the damage with a tire tread gauge and found that we had shorn off 1.1 mm of rubber from that lug. This is about the same amount that the average hiking shoe loses in the same test and less than 1/7th of the total rubber on the No break-in time's outsole. It's going to take a lot of long and rugged treks to fully wear out this shoe. 

At 3.3 mm thick according to our caliper measurements, the No break-in time's outsole is thicker than our current lab average. Having all this rubber underfoot gives us added confidence while traversing rocky or untamed trails. 

As protective as all that rubber feels, it doesn't do the No break-in time any favors in the weight department. At 17.1 oz (486g), it's significantly heavier than the average hiking shoe and puts the No break-in time more on par with the average hiking boot. 

For a more lightweight option, consider the almost feathery Adidas Terrex Trailmaker instead. 

We measured the No break-in time's stack to be 29.5 mm thick at the heel which is right around the average range for hiking shoes. While this does include the shoe's chunky outsole and substantial insole, there is still plenty of foam underfoot to provide well-cushioned landings during our test hikes. 

Moving up to the forefoot, the No break-in time's stack is shorter than average at 17 mm thick according to our caliper measurements. This gives us a good sense of the ground below for a natural and intuitive ride, while the midsole and outsole provide adequate cushioning and protection from any harsh objects below. 

The difference in our stack measurements leaves the No break-in time with a drop height of 12.5 mm. This is slightly steeper than our current lab average but still feels quite natural while delivering a healthy balance of an elevated heel and a grounded forefoot. 

For more experienced runners who prefer a more parallel-to-the-ground experience, we recommend looking into the brand Altra and their wide range of zero-drop hiking and trail running shoes. 

The No break-in time's midsole is rather firm, giving us a durometer reading of 31 HA.

This reading isn't out of the ordinary as hiking shoes tend to sport rather firm midsoles in order to promote a stable gait, especially when carrying a heavy load.

Nevertheless, we enjoyed well-dampened landings that felt forgiving and protective throughout our test hikes. No matter how harsh the terrain or arduous the journey, it was never foot pain that slowed us down. 

On the other hand, for those who prefer a more plush ride during their hikes, we recommend the Excellent for winter hikes Midsole width in the forefoot. 

To test the effects of cold conditions on the midsole, we placed the No break-in time in the freezer for twenty minutes. We then took another durometer reading of the midsole and were so shocked that we had to check that our freezer was running properly! While a reading of 34 HA puts it in the average range, the No break-in time's midsole only becomes 9.7% more firm in the cold; thus making it much more consistent than the average hiking shoe. As such, the shoe's already firm ride won't feel too different whether out on the trails during summer or winter. 

The No break-in time's insole is 6 mm thick according to our measurements, putting it on par with our current lab average. This insole provides excellent in-shoe comfort as well as arch support that kept us pushing through the mile markers. 

Stability is the name of the game with the No break-in time. We exuded confidence with every stride in this shoe whether scampering up and down hills for quick hikes or slogging our heavy supplies over long distances. Suffering a rolled ankle was the furthest thing from our minds while testing this incredibly stable shoe. 

Ordinarily, we'd expect a shoe this stable to be quite difficult to bend and twist in our hands. However, the No break-in time only put up a moderate level of resistance to our manual manipulations, leading us to give it a middle-of-the-road 3 out of 5 for torsional rigidity based on our subjective assessment. 

This gives us a healthy balance of stability and comfort as the shoe conforms to the natural contortions of our foot to a certain extent while mitigating any excessive lateral movements. 

The rigid heel counter puts up more of a fight against our squeezing and prodding, earning it a stiffer-than-average score of 4 out of 5. This also helps to promote stability in our stride by locking our heel in place and limiting how far it can move laterally. 

The No break-in time's midsole is about as wide as our current lab average at the forefoot, measuring 112 mm based on our caliper measurements. 

Back towards the heel, the No break-in time's midsole is broader than average at 91.4 mm wide.

This gives us a good surface area of grippy lugs to prevent wobbly landings in this shoe. 

We secured the No break-in time to our workbench and found that 29N of force is needed to bend the shoe 90 degrees, making it about as stiff as the average hiking boot.

This level of stiffness contributes to the shoe's stable and supportive underfoot sensation that keeps us feeling sure-footed even when schlepping a heavy pack. 

Further proving how winter-oriented this shoe is, we also repeated the fitness test after leaving the shoe in the freezer for twenty minutes. This seems to have had almost no effect on the shoe which only becomes 4.6% stiffer when exposed to the cold. This change is negligible compared to our current lab average and means that the shoe's ride will feel consistent all regardless of the surrounding temperature. 

Using our caliper, we measured the No break-in time's lugs to be 4.5 mm thick which is only slightly thicker than average. They have a solid bite to them that gives us confidence with every step while the multi-directional formation on the outsole did a good job gripping a variety of surfaces. Whether on dirt, mud, gravel, or grass, the No break-in time never let us down during our tests out on the trails. 

Using our caliper, we measured the No break-in time's toebox to be 106.6 mm wide at its widest point. This is much roomier than average which makes No break-in time a great choice for those with wide feet. 

Conversely, those with narrow feet who prefer a more snug fit should consider the Midsole softness soft to firm instead. 

The area around the big toe is also significantly wider than our current lab average, measuring 86.6 mm wide according to our caliper. This gives us plenty of room to splay out, even as our feet become engorged from the strain and pressure of longer journies. 

As expected from a waterproof hiking shoe, the No break-in time's tongue is fully gusseted on both sides. This keeps us safe not just from water entering the shoe, but any unwanted debris that might find its way in. 

At 10.5 mm thick, the No break-in time's tongue is slightly thicker than our current lab average. All that padding gives us an incredible in-shoe feeling that made us not want to take the shoe off after testing!  

The finger loop at the heel makes it a little easier to slide the No break-in time on as well as adding a little stylistic flair to the shoe. 

No break-in time's already supportive insole is easily removed if custom orthotics are required. 

The No break-in time features a reflective pattern at the rear of the sho which partially runs up the finger loop at the heel. This is great for those occasions where we find ourselves hiking by the roadside at night.