Welcome to Running and Rambling! Stay updated on product reviews and all new articles as soon as they're posted by subscribing here.

February 8, 2010

Vibram FiveFingers KSO Trek Review

In my original Vibram FiveFingers review last summer, I described the revolutionary product as a disruptive innovator for the manner in which it completely changed the market in ways that mainstream footwear companies never anticipated. Since that time, Vibram’s popularity has soared, and the shoe industry is still scrambling - sometimes thoughtfully, other times rather hysterically - to figure out how to respond.

And while their increasing appeal guarantees that Vibram won’t take anyone by surprise anymore, they continue to take the “innovator” label very seriously: between fall 2009 and fall 2010, they will have introduced no fewer than four new models to their product line, effectively doubling their previous lineup. Many of the tweaks and upgrades are driven by user feedback; since the activity profile of Vibram FiveFingers (typically abbreviated VFF) users is incredibly diverse, the company invites and embraces customer feedback about new applications and ideas for improvement. It was in just such a manner that the KSO Trek was born.

FiveFingers KSO Trek

In a nutshell, the KSO Trek is a more rugged version of the popular KSO model that I’ve reviewed previously. The KSO had become the de facto model of choice for trail runners – including myself – because to that point it was the most durable model Vibram had to offer. High mileage trail runners experienced some issues with durability of the uppers and traction of the outsole (this was the primary drawback I experienced), and Vibram has addressed both of those concerns quite effectively with the Trek, which is now identified on the company website as the designated model for trail runners.

The updates are fairly dramatic, and easily apparent. They’ve also triggered a bit of discussion among consumers for various reasons, which will be pointed out shortly. For now, let’s get to the review - starting from the top, and working our way down.

One concern identified by longtime VFF trail runners was the durability of the KSO’s mesh upper against various ground hazards. During any trail run, there’s a good chance that parts of the upper will rub against rocks, thick pine needles, fallen branches, and all manner of sticks or twigs that get jammed into the top of the foot or lodged between the toes. Some of these hazards would potentially cause punctures or loose seams with long-term use. Vibram’s solution to this concern is the use of kangaroo leather on the upper of the KSO Trek.

Plush kangaroo leather uppers

Kangaroo leather is a pretty amazing material – it’s incredibly soft and smooth to the touch, and feels like velvet against your skin. It is very thin with outstanding breathability, but is as strong and tear resistant as traditional cowhide. The specific kangaroo leather Vibram uses is called K-100, which provides excellent water resistance and a "microblok" anti-microbial treatment to help with the inevitable stench factor. However, it’s also a material choice that stirred up a bit of controversy when it was originally announced.

Although kangaroo products are a traditional commodity in the Southern Hemisphere, animal rights proponents in various locales have objected to its use over the years. As recently as 2007, it was illegal to buy or sell kangaroo products in my home state of California, but today kangaroo meat and leather goods are commonly exported all over the world. Although they’re much cuter than North American cattle, kangaroos essentially serve a similar industrial need Down Under – and in much of Australia, they are seasonally hunted like deer (because for obvious reasons, they’re harder to shoot than cattle) as a means of population control. Nevertheless, some Vibram users object to the notion of killing Kanga just to make a pair of foot coverings.

Part of this probably has to do with the fact that many early Vibram adopters were the barefoot crowd - a group that has traditionally had a distinct Earth-loving tree-hugging vegan peacenik hippie element to it. (Remember this ambush interview by the Raw Food folks?) For that particular crowd, any animal products will be cause for protest – but if you’re already a meat-eater or consumer of animal products, the use of kangaroo leather shouldn’t be a moral issue for you.

(Sorry for the digression. Stepping off my political soapbox now … )

The middle of the Trek features a 4mm EVA midsole, which is a full 2mm thicker than the standard KSO. It’s a tangible increase in cushioning compared to the KSO – which makes pure minimalist runners raise their eyebrows – but I didn’t notice any sacrifice in ground feel. You can still detect every bump and pebble on the trail, but your foot feels more comfortable on all types of terrain.

Rugged outsole

Underfoot, the Trek makes a significant upgrade from the KSO by using a lightly cleated 4mm performance rubber outsole for improved traction. In my KSO review, the only performance-related drawback I encountered was some slippage on steep slopes with loose gravel. I’m very happy to report that the new outsole is more than adequate to take on that kind of terrain, as well as any other trail conditions you encounter.

My Treks happened to arrive right on the cusp of our rainy season, so I’ve had plenty of opportunities to get them muddy and sloppy over the past several weeks. I’ve gone up and down rocky slopes, traversed muddy single tracks, and done quite a bit of rock-hopping back and forth across stream crossings. While the knobby outsole isn’t at the caliber of the grippiest shoes I’ve ever worn (in my book, that’s still La Sportiva's Wildcat and Crosslite, with the Salomon SpeedCross2 a close second), they perform as well as the majority of dedicated trail shoes out there.

Above the clouds on top of the Salinas Valley; no trail is too difficult for Treks!

From top to bottom, the Trek is an outstanding improvement over the KSO for dedicated trail runners: it’s comfortable, durable, and rugged, and built to handle any type of terrain. Best of all, despite all the augmentations to the shoe, somehow Vibram managed to keep the weight the same; the Treks weigh 5.7 oz each, identical to the original KSOs. The only thing that’s heavier about this model is the price.

This has been another source of discussion among VFF users: the retail price of $125, which is a significant increase from the $85 KSOs. Most of the inflation is attributable to the upper - apparently high-performance kangaroo leather doesn’t come cheap – and like all VFFs, there’s no “500 mile rule” for midsole breakdown, so the $125 you spend for Treks should last you much longer than the same amount for a pair of traditional trainers. But justified as the price point may be, it might be hard for some folks to embrace the benefits of “barefoot” wear that costs more than most bulky or high-tech performance shoes.

Consequently, the decision to go with the Treks over standard KSOs should boil down to your intended use. If you want something to use equally on roads and trails, or if your local trails aren’t terribly technical, you can probably get by with the regular KSOs. If you’re a devoted trail runner who takes on all sorts of terrain and wants something tough enough for all conditions, the Trek is well worth the investment.

From my standpoint, the Trek is absolutely ideal – it features all the improvements over the KSO that trail runners have asked for, while maintaining the lightness and ground feel of purely minimalist footwear. In fact, I’m so confident about their comfort and performance that doing an ultra in the Treks seems completely manageable. I’m hoping to build my overall mileage in them significantly over the course of the spring and summer, and I’ll keep you posted with updates as I look towards potential races in the fall.

Time to relax; Monterey Bay in far background (click to enlarge)

The Vibram FveFingers KSO Trek retails for $125 from TravelCountry.com as well as other online vendors.

*Product provided by Vibram USA
**See other product reviews on sidebar at right. If you have a product you’d like reviewed, contact me at

Get Running and Rambling delivered to your inbox! Click here to receive new posts via e-mail.


Moire O\'Sullivan 2/8/10, 6:28 PM  

Thanks for the excellent review. I've been wondering about getting a pair of VFF trek for mountain running (at the moment just have sprints for the road). Sounds like the treks are definitely worth a go... only question is, will they be able to survive the wet and cold of Irish mountain bogs?

Barefoot AngieB 2/8/10, 7:47 PM  

Great review and I love the photos!

Michael 2/8/10, 8:03 PM  

Well Don...this review and all your prior talk of barefooting is actually tempting me to give it a try! I'm always up for a new challenge...hmmm...

Marcus 2/9/10, 4:51 AM  

I own a pair of treks. I currently have about 200 miles of mostly trail running in them. A couple of weeks ago I did a 13 mile run in them -14F below zero. Feet toasty the whole time. They are the solution to keeping barefoot shape during the winter. Injinji wool socks help as well. My only complaint is my toes freezing in slushy conditions. I was thinking of coating the toes in silicone to fix this.

RD Jim 2/9/10, 8:03 AM  

What socks do you wear under these? How do the sizes run compared to say an Asics running shoe?

Tuck 2/9/10, 9:02 AM  

Barefoot Ted did the Leadville 100 in Treks this past summer. So an ultra is definitely within their reach.

And for the Vegan crowd, Vibram is rolling out the Kangaroo-free Trek Sport next fall.


Nice to see they continue to listen...

Donald 2/9/10, 9:15 AM  

Moire - I've gotten mine pretty wet and muddy, and the leather dries very quickly. If you have a moisture-wicking sock and the temperatures aren't too freezing, I'd certainly recommend them for your bogs.

Jim - I wear Injinji performance socks when I'm running for 2+ hours in VFFs (I'm praying for Drymax to invent a toe sock!). Under 2 hrs, I usually go sockless, but I start to have some abrasion issues when I'm out there longer.

As to the sizing, it's a whole different ballgame - Vibram measurements are based on actual foot length as opposed to shoe size, so you really should get measured in a store, or use the size chart on the website. I wear a US11/Euro 44, and I'm right in between sizes 42/43 for VFFs.

mweston 2/9/10, 1:58 PM  

I was going to ask about the socks I see in the photos, since I thought most people wore VFFs sockless. So that part's answered.

And I was also wondering if people used any lubricant on their feet with VFFs (I usually use Body Glide and socks with regular trail running shoes).

I just got my Treks Sunday and I haven't run in them yet, but I'm looking forward to it.

Ro Hunter 2/9/10, 4:01 PM  

,,,and the Vibrams start to look more and more like 'normal' trail running shoes. Now, if only they could be innovative and create a toe box instead of individual toes...

Anne 2/10/10, 6:44 AM  

Yes, it appears your original review was prescient. I gotta admit, I'm starting to like the way these things look on people's feet, and these appear perfect for trail running.

Drs. Cynthia and David 2/10/10, 11:17 PM  

As a veteran of some 1200 miles of rough terrain on my KSOs, I am not at all personally attracted to the Treks! The new features just don't add anything that I want. For a full discussion of why, see my recent update on my own experience with my KSOs.

Garrett 2/12/10, 9:24 PM  

Makes me miss Monterey! My friends got me interested and now I am looking at buying a pair this weekend...my question is whether or not the treks will stand up to heavier backpacking (or rather, would it be recommended to take a heavy load on the John Muir this summer after I get used to them?). If so, treks it is, if not, KSOs so I can save a few $$!

Donald 2/12/10, 10:27 PM  

Garrett - I'd definitely recommend the Treks for that kind of serious hiking. The leather upper is super comfortable, and the traction is noticeably better. Whichever model you get, be sure to build up your time in them gradually.

Anonymous,  6/13/10, 9:28 AM  

I want to start hiking, not running, but hate the heavy walking boots, wondering what your thoughts are on Treks as an alternative? Thanks

Donald 6/14/10, 8:53 AM  

Anon - I think they'd be great for hiking, assuming you allow for the same adaptation period that's necessary for running. If you go out and try something strenuous in these right away, your legs and feet will let you know about it. Once you're accustomed to them, no problem.

You might also be interested in this Yosemite hike post if you haven't already seen it.

Anonymous,  7/31/10, 11:18 AM  

How are the Treks for road running? As much as I love trail running, the reality is that most of my running is on the road so I'm a little nervous about the Treks vs. the regular KSO.

Donald 8/1/10, 9:30 PM  

Anon: the Treks are pretty much built for the dirt. You could wear them on the roads, but the grippy outsole would wear down relatively quickly. For asphalt, I'd stick with the KSO, or the new Bikila, which I plan to review soon.

Vibram Chris 8/16/10, 5:06 AM  

Excellent review. I am loving my Treks. But I have found that after an hour or so in the heat and humidity they require frequent adjustment with the strap and other leather stretching over time. When they dry the shoe materials return to the original dimensions.
Have you noted this?
I have added an extra piece of velcron toward the heal and will try some stretch laces over the top of the shoe.

Donald 8/16/10, 6:57 AM  

Chris: Yes, I do find myself tightening the strap occasionally once I've been on the trail for an hour or two. We don't have crazy heat or humidity here, so I'm guessing it's more related to the leather. I haven't had to augment the fastener in any way, however.

Josh 8/20/10, 10:02 PM  

Awesome review. I have sprints and love them but wanted to get more into trail running, thanks.

Anonymous,  9/12/10, 6:33 PM  

I was just wondering if you think the Treks have a more durable upper construction compared to the sport treks.

Donald 9/12/10, 7:22 PM  

Anon: I haven't tried the sport treks yet to compare (perhaps later this fall?), but the leather uppers on this version are super-durable; I haven't had any issues with split seams or punctures whatsoever.

Anonymous,  9/17/10, 12:37 PM  

this is anon. who asked about durability of treks. Just got my brown treks from city sports. They are very comfortable but I have some initial concerns.

The heel in one seems to not be glued to the sole all the way.

Also the fabric near the big toe doesn't appear to be symmetrical. Basically one has about an inch more of fabric, not in space but in length. A minor issue, but is this normal for Vibram?

Also there is glue visible on the toes. Normal?

Are these known issues of the trek? I'm a little concerned that at the price point of $125 I'm not confident in the build quality of these.

They seem to have less issue with fabric. I don't notice any of these issues with my KSO's

Donald 9/19/10, 5:12 PM  

Anon: those don't sound like any known issues I've heard of, and I haven't experienced any of what you're describing on my own pair. I just double-checked all the seams on mine, and I can't find any spots of glue separation.

Assuming you got them from an authorized vendor (i.e. not a knockoff), it sounds like you'd have grounds for a return - especially with the glue issue. Keep me posted, please.

Lorne 11/14/10, 11:07 AM  

One thing I noticed when I got my treks is that they seemed to fit a bit bigger than my regular KSO's. I've been wearing them constantly fr a couple months now and haven't had any major issues from this, but if you have the option it might be worth it to go try a pair on. I just assumed they would be exactly the same as the KSO regulars, but I think the different materials change the fit somewhat. I have a pair of 45's, but when I originally tried on the KSO's in the store, the 44's were just slightly too snug, so it's a close thing. Other than that, they're awesome! I work outside as a window cleaner and tow all my equipment by bicycle, and these are so comfortable, I don't want to take them off.

zeephyyr 11/16/10, 10:45 AM  

The seam that binds the leather to the fabric piece that covers the inner side of the 1st toe of the left shoe burst after a few runs. To be more precise, the thread that joins one piece to the other got broken by the tension force pushing both pieces apart. Vibram should have picked a thread made of more resistant material to sew the upper pieces together. My repair is noticeable because I couldn't resew the seam from the inner side.

KSO Trek leather seems rather stretchy. The shoes now fit too loose without socks. Even with socks, the heels can slide on the leather insole when running on more technic trails, probably due to the fact that now I can't get a very tight fit.

If you just want them to run on trail, my advice is you get TrekSports instead, they fit snugger, have more resistant seams and won't stretch that much over time.
On the other hand, if you want to wear them for several hour a day, leather Treks have a more comfortable fit and breath much better.

Anonymous,  1/4/11, 11:07 AM  

I am going to be running through an obstacle course that has mud, water and pretty much everything that will test these shoes. What is your opinion on these shoe standing up to these conditions and making it out alive.

Donald 1/4/11, 8:56 PM  

Anon: I've worn them in all of those conditions; I'm sure they'll be fine.

Lorne 1/13/11, 12:40 PM  

After about 4 months, I've developed quite a few holes between the toes, I'm wondering if this is usual. My regular Kso's never had this problem.

Anonymous,  1/8/12, 4:14 PM  

I like to buy from REI because if and when I have issues, they have no problem replacing the offending item.

Anonymous,  3/11/12, 8:38 AM  

I own 3 pairs of vff's, and my only problem with them is that the material on the inside of the big toe of all 3 pairs has torn all the way along the toe. I run a little more extreme of trails than most and don't think most people would experience this problem. They are still completely usable but I get rocks/dirt/sand in them

orschiro 10/4/12, 7:03 AM  

Thanks for your great review!

1. Is this leather Trek model usable for running (10km to half marathon distances) or do I then really need models such as the sprint model?

2. How does this show behave in wet conditions?

3. Is the show suitable for winter?



Donald 10/4/12, 9:29 PM  

@ Robert: I think your answers can be found in the review.

orschiro 10/7/12, 1:25 PM  

@ Donald,

I found most of my answers in the comments. However, still I would like to know whether this shoe is suitable for running over long distances on asphalt and how it usually behaves in cold winters.

Donald 10/8/12, 7:20 PM  

@ Robert: It's fine for running any distance you'd like, but on asphalt the outsole knobs will wear down faster. It performs well in mud and snow, but can be slower than synthetic mesh to dry afterward.

orschiro 10/10/12, 12:44 AM  

Thanks Donald.

I've got one last set of questions though.

Yesterday I received my Trek KSO leather, one pair in size 43 and one in 44.

1. I wondered about their made in China label since I read somewhere that they were normally produced in Italy. What about your Trek?

2. At some parts where leather and sole stuck together, the quality is very poor with the glue breaking away. Did you experience the same?

3. The size problem. 43 fits like a second skin. Especially my big toe has no space left whilst my other toes have a bit of space. 44 one the other hand leaves a bit more room to the big toe but again a lot of space to the other toes. Besides the toes both sizes fit my feet well.

However, especially in the winter I would like to wear wool socks. Should I therefore take 44?

Furthermore I read, that it's not even bad to leave a bit of additional space which will keep the air circulating and the feet warmer. What do you think?



orschiro 10/11/12, 12:21 AM  

Here are some pictures of the poor quality.




Is that normal?

Donald 10/11/12, 7:41 AM  

@Robert: My pair say made in China also. For sizing, I prefer slightly large to slightly small, to allow for socks and also for swelling of the feet with long activity.

For the quality/durability issues, I haven't experienced any of the problems you're describing. Might be best to contact Vibram directly about that.

Related Posts with Thumbnails

  © Blogger template The Professional Template by Ourblogtemplates.com 2008

Back to TOP