Montrail FluidFlex ST and Bajada II Review

I’ve been a huge fan of the FluidFlex series by Montrail for awhile and reviewed the 2nd version of the shoe right here.  This current review will also cover the Montrail Bajada II, a beefier trainer that harkens back to the days of old school trail shoes.

montrail fluidflex montrail bajada II
FluidFlex ST on the left, Bajada II on the right

Montrail FluidFlex ST

First, let’s get the confusion out of the way. The FluidFlex ST is not the same shoe as the FluidFlex II, which was released at about the same time.  The ST that I’m reviewing here appears to be a more stable version of its partner.


Initial Thoughts

Awesome, this looks like a light and fast trail shoe, just like the FluidFlex from last year. Same little square lugs, similar upper, tough toe guard for kicking rocks.  I recall not being overly impressed with the original, but then loving them on the trails, so I was sure to save my thoughts until I got these suckers on my feet.

My female reviewer Erica said:  When I first opened the box to the Montrail Fluid Flex ST’s, my initial reaction was how mild the colors were in comparison to the electric neon’s of most other brands at the moment. I liked them and their toned down color scheme. I wear a size 8 and have a mid-range width foot. If you have a wider foot it might a little on the slim side. I decided to wear them around for a day before my first run to see how they felt. They were plenty comfortable although by the end of the day the tops of my feet were pretty sore. 

Female version of the Montrail FluidFlex ST
Female version of the Montrail FluidFlex ST


I wear a 12 in most shoes, and this fits a tiny bit on the big size, but nothing uncomfortable. I also prefer a narrow toe box (I’ve got narrow feet), and these suit my needs well.

Erica said: I also noticed that the heel cup is much taller than my regular shoes (Brooks Pure Grit 3), so super short socks are out because this rubs on your Achilles and the socks work their way down to your toes. With the proper sock height the heel fits nicely and grips your heel.


I tend not to get too deep into the construction of the shoes, but this is a lightweight trail shoe. Nothing fancy, and no special new technology stands out, but this is a light (10oz for size 12) shoe that really does offer a bit more stability than its predecessor while keeping the shoe low, light, and flexible. Not an easy task, as shoe designers often bulk up the shoe unnecessarily.


There’s a rock plate in the heel that is effective when you land directly on it.  I couldn’t find dimensions of the plate, but it doesn’t seem to cover much of the heel area.

One issue I’ve got is the “mesh” used in the forefoot, heel cup, and tongue.  It doesn’t appear to offer any additional venting properties, but instead unnecessary catches ever bit of dust, dirt, and burr on the trails.

The mesh I don't like.
The mesh I don’t like.

Erica said: The upper is a mesh construction with screen printing along the sides for extra support, this keeps the shoe light and flexible. The toe is guarded with some extra reinforcement which is a toe nail saver especially if you tend to trip or kick rocks during your run. 

The laces stay tied and the tongue stays put with the double stays that are sewn onto the tongue. I had no problems with it going off to one side of the shoe.

If you run in high weeds or stickers beware because they stick like crazy in the top mesh and fabric of this shoe and are difficult to remove. I have that problem running in the dry weeds of northern California. 
The sole uses Montrail’s Fluid Foam which is different foam densities to allow for stability. This foam gives the shoe great cushion but the soft foam of the mid-sole I’ve noticed wears quickly if you are on any gravel or very rocky terrain. On pavement, since this is mainly meant for trail it’s very sticky. Stick to the dirt, its the best place to be anyway. Montrail uses Griptonite in the heel and forefoot for traction which works great on the dirt and sandy trails. I have don’t have the terrain to try them in the slippery mud of the east! So the missing traction in the center of the shoe might become an issue in other elements.

How do they feel?

I’m happy to report that after 200 miles, this shoe still feels great. It’s kept much of the low and light qualities I like, while providing just a bit more stability and contortion control over technical terrain.  The FluidFoam used in the last has a soft feel to it that doesn’t lose its effectiveness on the trails.

Gryptonite squares after 200 miles!
Gryptonite squares after 200 miles!

Erica said:  My initial run in them was an eight miler on a mix of gravel, wet rocky hard-pack road and single track with a bit of high weeds thrown in. From start to finish in the run I had no issues with hot spots or adjustments. The traction was great in gravel and on the wet hard-packed up hills. All of my additional runs on varied terrain of pavement, gravel roads and technical single track, they performed well. I also used them on my shorter runs with speed work, they were responsive enough but definitely think they perform greater in longer distances. 


Solid.  I’ve beat these up pretty bad and have no issues at all with tears and snags, and after much of my mileage on decomposed granite or blacktop, the lugs and last are holding up well.


Montrail took a low and light trail racer and deftly modified it without losing the original shoe feel. If you like low, light, and flexible shoes but also like some stability, there aren’t many shoes to choose from.

Price…less than a hundred bucks!


A few extra ounces were added.

The “achilles pads” found in the original are missing from this model.

The mesh used in the forefoot and tongue creates a mess.


Who’s the shoe for?

I’d recommend this shoe for the multi-use trail runner who prefers low/mid drop, likes moderate groundfeel, and appreciates a traditional trail show without bells and whistles.  If I’m going out for 2 hours or more on mixed trail at a moderate or aggressive pace, this would definitely be a shoe I’d consider wearing.

Erica’s conclusion: Comparing them to my other shoes the Brooks Pure Grit 3 and the Newton Boco AT, I like the Montrail better than the Newton for weight, flexibility and breathe-ability. I do love my Brooks but comparing the cushioning, for longer distance I think the Montrails would be nicer to my feet. The two downfalls I find with them are the high heel cup and the soft, easily worn foam on the sole. So overall I like the shoe, the grip, the stability and the look. The price is also very reasonable compared to others. I would probably purchase this shoe for myself and recommend it to pronator trail running friends that are looking for a stable shoe for distance.


Weight: 10.2 oz for my size 12

Price $95

Stack height/drop: 15mm/11mm

More info here

Montrail Bajada II 

And now for an entirely different shoe…

Summary:  The Bajada is a traditional workhorse of a trail shoe, ready to take on hundred milers through any terrain. This thing is old school and tough, but made with modern materials and technology.


First Impressions:

The Bajada II is obviously from the same family as the FluidFlex ST and has telltale Montrail qualities like the Gryptonite sole (love it!) and the meshy upper (grrrr), but harken back to the day of beefy and indestructible trail shoes like the Montrail Continental Divide.

This thing isn’t light and when twisted with my hands, doesn’t show a lot of lateral flexibility.

Where the FluidFlex’s sole has a segmented pattern of lugs and Gryptonite squares, the Bajada II has a full complement of the little lugs, save for one small section on the back.


Similar to other Montrail shoes, it’s a bit narrow in the forefoot (which I like), and it runs a tiny bit big. Size-wise, I’d wear a 12 1/4 if they made it, and this is perfect.



This shoe definitely feels beefier than most other shoes I wear, but the weight wasn’t as big a factor as I figured it would be.

Reasonably cushioned and supportive, this thing is made for tough hundred milers.  The landing is soft and controlled and the heel cup and collar keep everything in order.

montrail bajada II
Female version of the Bajada II


Unlike the FluidFlex, I’ve only put about 100 miles on these, but they’ve held up just as expected.  No major wear and tear, and the the little square lugs are still effective.


Tough shoe with decent traction that’s begging to run long over any terrain.

Quality build.


Meshy upper drives me nuts

Definitely needs a beefier toeguard. Why does it’s light and fast brethren have it, but this tank doesn’t?



My size 12 weigh 13.5 oz.

Price $130.

Stackheight/drop: 20mm/10mm for a 10mm delta.

More info here.

Who’s the shoe for?

This shoe is for people who either really prefer a big and traditionally stable trail shoe, or those looking to add to their stable of hundred mile shoes.

Full disclosure: Montrail provided these shoes to me for review purposes. All words are my (or Erica’s) own.





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