The FluidFlex is a brand new shoe for Montrail in 2013. While not specifically marketed as such, it’s been suggested that this can be considered a hybrid road/trail shoe – something ideal if you need to beat some pavement on the way to the trail head. I must say that I am always a bit skeptical of “hybridized” products, and have tons of specific-use gear to show for it. However, in the running shoe world I think there is enough grey area between superlight, fast road shoes and full protection, big lugged trail shoes that the hybrid concept is possible. With this in mind, I set out to try these shoes in both conditions and see how they fared.
These are definitely light shoes. Montrail has the minimal, lightweight Rogue Fly in their lineup and the FluidFlex are nearly the same weight. They are also lower drop with an advertised difference of 4mm between heel and forefoot. The cushioning as advertised in 15mm in the heel and 11mm up front.
The tread is really where the hybrid idea can fall apart in a running shoe. The FluidFlex forefoot tread uses a familiar Montrail pattern of square blocks in sort of a random pattern. I know from past experience that this simple lug design really works to grip on the trails. Again, in the FluidFlex I was impressed with my ability to hold traction on slippery, snowy, muddy trails. I also found that the sole design worked well on hard road surfaces as well. The lugs were spaced close enough together, and the rubber was firm enough, that I didn’t feel any sponginess or twisting on contact with the ground. The channels between the rubber lugged pads on the sole made this a very flexible shoe – again more road-ish than traditional trail. The result of all of these features was that I was impressed with just how fast and light I felt while running on the road in these shoes. They obviously weren’t racing flats, but they felt every bit as road worthy as any other good lightweight training shoes I’ve used. I haven’t put enough km’s on these shoes to comment on their durability, but based on the similar tread on my rogue flys, I’m not concerned about premature wear.
The FluidFlex are low drop, but still have ample foam to protect your feet from the ground. I noticed the cushion when I used them on the road, but I didn’t feel like it was slowing me down or stealing the energy I was putting out. They felt like the kind of shoes you could pound the pavement in for a long time without pain. On the softer trails, the squish was less apparent, but the impact from roots and rocks was definitely dampened significantly.
The upper on the FluidFlex was more like a traditional road shoe than a hardcore trail shoe. I liked this. I find that much of the time I am running on well trod trails where I don’t need as much heavy duty protection on the toe and top of the shoe. The FluidFlex struck a nice balance with a bit of heavier toe fabric coverage for durability and minor protection from kicking the odd trail obstacle, but not a full blown toe cap that would add weight. These uppers were very well ventilated. Since I was using them in the winter, this was quite obvious! The good ventilation was a result of the relatively simple upper. The outer fabric is all one piece of very porous material, while the inner structure was provided by a few stiffer “ribs.” The overall feeling was very light and spacious. The toe box felt open so there was no issue with my forefoot feeling cramped, and actually it took some time to get used to the spaciousness. Once I got the socks and lace tension right, they felt good on my feet. That being said, I would suggest trying them on because I would consider potentially going a half size down in this model. As a point of reference, these felt much roomier than the same size in the Rogue Fly.
Montrail seems to have nailed it in terms of developing a shoe that works well on both hard road surfaces and typical trail surfaces. I would wear this shoe in all but the extreme ends of those two spectrums. If you are looking for a light and fast shoe that is more than adequate on and off road, give these ones a try. The only thing I would watch out for is to make sure your normal shoe size equates to what feels good in the Montrail FluidFlex.
As always, thanks for reading the blog and feel free to send me any questions I haven’t answered.
I haven’t owned a pair of Montrail’s, but these look very interesting. I have tried a few on, and the pair I liked the most was the Rogue Racer (light and low), but I found that it was a rather wide-fitting shoe and wasn’t well-suited for my narrower feet. These look narrower than the Rogue Racer. Have you tried those and how would they compare? Not sure if the Rogue Racer is similar to the Fly?
The FluidFlex fit snug through the midfoot but they definitely open up at the toe. I think the rogue fly is a bit narrower than the racer, but the FluidFlex is definitely wider than the rogue fly. It fits more like a lot of the new zero drop/natural fit road shoes. Lots of toe box room to let your toes splay.
I found the Rogue Racer was a little wide in the heel – had a bit of slippage. These look interesting and will definitely give them a try next time I see them in a store.
Great review Kent, thanks!
How is the heel cup? I have had an Achilles insertion surgery a year ago. It doesn’t like hard heel counters. Unfortunately most trail shoes a stiff in the heel. I’ve struggles to find one that will work for me. Thanks
Thanks for reading and for your question. The heel cup on the FluidFlex has some structure but is still quite flexible. Rather than a stiff plastic cup, it feels more like a thin piece of foam to give it shape. There is about 1″ around the top that is just fabric. Worth a look as its much less stiff than many trail shoes.
Thanks for the review. I just ordered a pair. The types of trails I run are dry desert and pretty compact. My Nike free’s are getting torn up. I’m stoked for the new rides!
Thanks for checking out the review. Enjoy the shoes – they should be awesome for that terrain!
Hi Kent. I purchased a pair of the FluidFlex and love almost everything about them. They are just what I need, lightweight, flexible with the perfect amount of cushion. The problem I am having with them is that dirt is getting in the shoes while running. They do feel like I should go down a half size…do you think that would make the difference? I had to stop to shake the dirt out twice during a 20 miler. That won’t do for me.
Would love your thoughts on this. Thanks!
Yeah sizing down might help if it seems like too much space around the ankle and heel that is letting stuff get into the shoe. I always wear thicker injinji socks with them and find they fit much better. I find the space more in the toe box which fills up with thicker socks.
Thanks. Running 13.5 this morning. I’ll give it a try with my thicker Injinji’s.
Hopefully that works for you. Thanks for checking out my blog!
That was the ticket Kent. Thanks so much…now I am completely in love with these shoes!
Can you discuss the stability features, if any? I’m looking for a very similar shoe, but without any arch support or other “form-correcting” modifications. Thanks!
Can you comment on any stability features? I’m looking for a shoe that has NO arch support or other “motion control”-type stuff. Thanks!
Hey Jeff. Thanks for checking out my blog.
These have a bunch of foam, but no real control features. They sort of like a soft slab of foam underfoot – that’s it. They’re super flexible in every direction and don’t do anything but cushion. I liked them because they weren’t trying to guide my feet anywhere (like a minimal shoe) but still cushioned lots of impact (less minimal but still good).
I’ve been using them mostly on the road this winter and love them. When on the trails they hold up great as well – did about 20km in tons of mud on the weekend and they gripped well.