The Montrail FluidFlex F.K.T. is a versatile, performance trail running shoe designed for a neutral foot motion.



Get from point A to point B in record time with the Montrail FluidFlex F.K.T.  Designed for the experienced runner to set a F.K.T (fastest known time), this versatile trail shoe is ready to pick up the pace. A full length FluidFoam midsole offers high energy impact absorption while FluidGuide Technology provides a smooth ride on uneven terrain. Paired with a Gryptonite Trail outsole with a Micro 3 Point Lug design, the FluidFlex F.K.T offers sticky traction on the trails.

Model Number:

Weight: 9.7 oz (size 9)

Stack Height: Heel (22mm), Forefoot (18mm)

Widths Available: D=Medium

How It Fits (based on width D)

  • Sizing: Fits large; purchase 1/2 size smaller than standard running shoe length
  • Heel: Medium  to narrow
  • Mid-foot: Medium
  • Forefoot: Medium to narrow
  • Toe-Box height: Medium
  • Arch Structure: Medium
  • Shoe Shape: Semi- Curved
  • FluidFoam is a full length compression molded foam that offers high energy impact absorption and increased durability.
  • Articulated Midsole Flex Grooves run horizontally and vertically through the midsole for increased flexibility and support.
  • FluidGuide Technology provides a smooth ride on uneven trail surfaces.
  • Gryptonite Trail is a sticky outsole rubber designed for optimal traction and durability on both wet and dry surfaces.
  • Micro 3 Point Lug design is lightweight and provides multi-directional grip on trails.
  • Forefoot TrailShield provides added protection without sacrificing flexibility.
  • Open Mesh throughout the upper offers lightweight breathability
  • Seamless Construction provides a smooth, irritant free environment.
  • Lightweight overlays offer a flexible, supportive fit and high breathability.
  • Traditional Sockliner adds underfoot comfort.
  • Anatomical Fit mimics the shape of the foot, resulting in a glove-like feel and allowing the the foot to work as a single unit.
  • Strobel Last with the upper stitched to full length fabric for a comfortable underfoot feel.

Footwear Performance Characteristics

Pronation Control: What's This?

  • Neutral
    • Min
    • Mod
  • Support
    • Min
    • Mod
    • Max
  • Motion Control
    • Mod
    • Max

Heel-Toe Offset (mm): What's This?

  • 0
  • 1-2
  • 3-4
  • 5-6
  • 7-8
  • 9-10
  • 11+

Stack Height:

  • Barefoot
  • Minimal
  • Low
  • Medium
  • High
  • Maximal


  • Road
  • Road-Trail
  • Hard Trail
  • Varied Trail
  • Soft Trail

Shoe Type:

  • Premium
  • Standard
  • Performance
  • Racing

Customer Reviews

Comments: I loved the FluidFlex II, so much so that I bought it out when I could find it in my size. It was the perfect combination of light, just enough traction yet fast, priced well, and even looked good (to me). For example, I ran a 50k trail run in a brand new pair of FluidFlex II and my feet were in great shape. I have one pair left in the closet. I ordered the FluidFlex FKT when I couldn't find anymore of the II in my size.

The FKT is a solid light duty trail shoe, good for mixed surfaces. In comparison to the II, it is noticeably heavier and stiffer to me, but still lighter than most shoes and about average stiffness. My FKTs are about 3.5 months old now and probably over 300 miles in, and I thought I'd break them in so they were as flexible as the II, and I thought I'd get used to the weight, but neither has really happened. Compared to the II, these are still heavier, stiffer, and don't breath as well. Compared to most trail shoes and a lot of road shoes, these are lightweight and fast, and average breath-ability and stiffness. I like the added durability but not the added weight. I like the added warmth in December but not the decrease in breath-ability. I still really, really like the sole and tread pattern.

I'll buy another pair of the FKTs, but I'm also going to start looking for a better replacement of the FluidFlex II if Montrail continues to move the FluidFlex to the heavier end of the shoe spectrum.
From: Anonymous, CO, USA. December 28th 2016

Comments: Great shoe... If it would last.
I'm struggling to find a shoe that would work for me (wide feet) and was very pleasantly surprised with this one. It fits, holds foot in place on tough terrain (unlike Altra) and everything was just great. Unfortunately, after ~100 miles on mountain trail both soles fall apart.
Therefore, I'm changing my opinion from very positive to very marginal. For an easy trail, I probably would still give these shoes another chance.
From: Anonymous. August 14th 2016