Vibram Five Finger KSO Review

Posted: August 17, 2011 in Reviews, Running
Tags: , ,

It’s time that I give some much needed blog attention to my go to minimalist shoe, the Vibram KSO I first became a Vibram Five Finger fan when I saw them while in college in early 2008. At this time, I was drawn to the classic, however, being a poor college student, it wasn’t in the cards for me to have a pair. This takes us to 2011, graduated, working a decent paying job, and I’m finally able to afford a pair of Vibrams. My first Vibram purchase was actually the Bikila. However, I found my KSO’s shortly after via a sale from They were 33% off, and I immediately jumped on this amazing deal. I ordered the black KSO, and I haven’t looked back since.

KSO, which is an acronym for Keeps Stuff Out, does just what it says. It provides a near barefoot feel while keeping all but the finest dust out of your shoe. It is also the first five finger that Vibram created with an entirely closed upper. This upper, however, is not restrictive, and it is extremely flexible. To me it feels like a snug sock. In fact, the upper has no structure to it whatsoever.

The strapping system also changed. This was the third fastening system that Vibram had implemented. The first, of course, was the bungie system that was utilized in the classic. Many of you know that most classic owners mod their classics to remove the bungie cord. The spring used a system similar to the KSO. It was complicated by the separation of the heel straps and the top of the foot straps. This made adjustments difficult, and would often lead to frustration. With the KSO, the strap is a single piece of material that is threaded through either side of the shoe and behind the heel. This provides a one strap tightening system that allows for easy adjustment on the fly.

One complaint of the KSO strap system can be found with the eyelets that the strap is looped through. It seems that over time, the eyelets rub into the strap and cause the strap to fray. This can be seen in the photo on the right. As you can see, my strap is starting to show signs of wear and tear on the sides that come in contact with the eyelet. It seems that the damage is actually caused by a poor choice in material. This issue could be remedied with either a sturdier material for the strap, or with a smoother eyelet. It’s not to say that they eyelet is rough, but it must be rough enough to cause friction against the strap. My KSO’s have about 200 miles (walking/running) on them, and the strap is JUST beginning to show wear. However, I’ve heard of other experiences on the web where the straps fray much sooner than this. So, the mileage may vary.

The sole of the KSO is slightly thicker than the classic and sprint models. 2mm thicker to be exact. Having never worn the classic or sprints, I cannot say how much of a difference this makes in the groundfeel. It does, however, maintain the flexibility that Vibram is famous for.  What I can say is that the groundfeel of the KSO is not as good as the feel that I get in my huarches. The difference in overall thickness between my huarche sole and the KSO sole is 3mm. The huarche being 4mm and the KSO being 7mm. The sole is durable, however, I do not believe that my soles will last the 1,000+miles that some owners claim to get out of their vibrams.

As you can see in the picture to the right, my soles already show some noticeable wear in the forefoot area. This is the sole of my right foot, and the hole that is beginning to develop is exactly where my thickest padding on my foot is. It makes sense that this would be the first place to wear down, as with barefoot running, minimalist running requires a forefoot strike. My left shoe shows similar wear. This leads me to believe that the sole is not as durable as some have said they are. I do believe that once a hole is worn in the sole, a simple dollop of shoe goo would fix it just nicely As you can see, there is no other noticeable wear on the sole of the shoe, and I am quite happy with their durability. I would like to touch on the ramifications of reduced groundfeel. As I said, the KSO does provides good groundfeel, however, it does deaden the sensors in the foot enough that if I am not careful I can find myself landing much harder on my forefoot than I would barefoot or in my huarches. I do not feel that this is a major issue solely for the KSO, but for all vibrams in general. Vibram has started the trend of slightly increasing the thickness of their soles with each new model of shoes. With this ever increasing thickness, I fear that new minimalist/barefoot runners will fall into the trap of doing too much too soon because they are not getting adequate feedback. This is something to watch out for.

This sole does preform very well on almost any kind of surface. I’ve logged 100 miles or so on trails and roads in my KSOs and I never felt like I wasn’t secure in them. I’ve also worn them tubing down the Illinois river, and the grip on the slippery river rocks was not exactly the best, however, I gladly traded the grip for the protection that the Vibram rubber offered me. So, unless you are spening 90% of your time in the water for your running, you’ll find the grip perfectly adequate for all but the most technical of trails.

As far as sizing goes, there are reports that the all black KSO’s run a bit small when compared to their other colored brethren. My black KSO happen to run the same size as my Bikilas. I wear a size 43. When I initially put the KSO on I thought it felt a little tight. However, that tightness quickly abated after a few hours of wear. My best advice is to try them on if at all possible before buying. Or to buy two pairs and send the wrong size back. I know this may not seem economical, but the fit of these shoes is very important, and it’s hard to get it right if you’ve never tried a pair on before.

I do have a major complaint with Vibram itself. It seems that their manufacturing quality varies from batch to batch of each shoe. Or perhaps I should say that their quality control is not as high as it should be given the popularity and price point of their shoes. When I received my Bikilas there was not a single thing wrong with them. However, after the first week of owning my KSO’s and maybe 10 miles on them total, I noticed that the sole was starting to separate itself from the material on the inside of my left big toe. This caused alarm, and I immediately took to the internet for solutions. Rather than sending the shoes back, I decided to use some Krazy glue and glue the sole back to the fabric. As you can see to the left, the glue left a white residue on the seem between the rubber and the sole, not that it is an issue as it is hidden from sight unless deliberately pointed out. What alarms me is that the glue would be coming undone at such an early stage in the product’s life. I believe if Vibram is going to continue to add shoes to the market, and continue with the higher price points, their quality should reinforce their price point. I do not expect there to be anything wrong with an $85 dollar pair of shoes with less than 10 miles of wear in them. This is something that seems to vary between batches and models.

That about wraps up my review of the KSO. Not only is this shoe a very capable running shoe, but it is also my go to shoe for work. I do 95% of my running barefoot, unless I’m specifically testing shoes for review so the KSO has found itself relegated to my work shoes. I work in a business casual office at the county hospital here, and I find that the all black KSO is not as noticeable with my business clothes. However, I would not recommend wearing these to work in a conservative office or an entirely business style office. If you have any questions or can think of something that I may have forgotten feel free to let me know in the comments.

Until next time,



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