Fox Union Flat shoes review – a top choice for flat pedal riders

Fox have a great rep for making MTB gear, so how does the brand's recent foray into flat shoes fare?

Fox Union Fat shoes
(Image: © Rich Owen)

BikePerfect Verdict

Grip that's up there with the best around combines with sturdy uppers and a decent weight that results in one of the best flat pedal shoes you can buy.


  • +

    Superb pedal grip

  • +

    Robust and supportive

  • +

    Clean up well

  • +

    Treads 'comfort vs feel' line well


  • -

    Cheap, short laces

  • -

    Heavier than Five Ten rivals

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It's been a long time since Fox last brought out a flat pedal MTB shoe, which is a bit odd given its gravity and moto focus. But the brand righted that wrong earlier this year with the release of its Fox Union Flat shoes alongside two clipless models. The originally released models were also joined by the Union Canvas shoe last month.

I've been putting the Union Flats to the test for several months now in conditions ranging from hot and bone dry, to sopping wet and properly filthy. So, how did they fare and can they challenge the dominance of Five Ten's ever popular Freerider Pro?

View of the soles of two MTB shoes side by side

The Freerider's Dotty sole pattern is deeper and more pronounced than the Union's hexagons (Image credit: Rich Owen)

Design and specification

Fox has devised it's own rubber sole formula for the Union Flats, which the brand has dubbed Ultrac. It's got a similar feel to Five Ten's Stealth and Specialized's SlipNot compounds, which is a good thing as they are two of the grippiest flat pedal shoes around. Like Specialized's flat shoes, the Unions also have hexagonal lugs on the sole, but the ones on the Fox shoes are more wider, shorter and more tightly spaced.

The one-piece uppers are manmade with sturdy toe boxes and reinforced heels. The shape is more akin to the slightly deeper fit of Specialized's 2FO Roost shoes, than the lower cut Freerider Pros. Though the Union Flats sit in between the Five Tens and Specialized shoes in terms of overall depth. A thick midsole gives plenty of comfort and arch support too.

My test pair of size 44 EU Union Flats weigh in at 838g, compared to 748g for the Freerider Pros and 728g for Specialized's 2FO Roost Canvas – both size 44 too.

A pair of MTB shoes on some gravel

One-piece uppers keep splashes at bay, despite ventilation holes on all sides (Image credit: Rich Owen)


I've been riding in the Fox Union Flats in dry dusty conditions as well as sopping wet and muddy, and they've performed admirably throughout. The Ultrac rubber sole is a grippy as it gets but you're still able to make small foot adjustments on your pedal if need be.

The shoe feels comfortable and protective, but not as tank-like as the likes of Ride Concepts' Tallac. Pedal feel and feedback is decent, but the sensations are not as quite apparent as when wearing Five Ten Freerider Pros, due to a thicker midsole and a sole that's a tad stiffer – though this means more efficient power transfer to the cranks. Feel is very similar to Specialized's 2FO Roost shoes though.

Water splashes and trail filth are mostly kept out of the shoes – aided by the stitch-free molded uppers – despite having ventilation holes on three sides of the shoe. A snug ankle section helps keep things drier too.

The plastic uppers clean up very well, even after being properly tarred and feathered by trail chunks and ooze. My only real gripe is the laces – which are basically the same as you'd find on a regular sneaker/trainer and have frayed rapidly. They're on the short side too – even with my narrow feet.

Durability-wise, the shoes are doing pretty well after a few months use. The soles show some pedal wear, but that's par for what I'd expect in a high grip pair of MTB shoes on sharp pedal pins.

The Fox Union flat shoe in the woods

The Unions are still looking good after a couple of months. I'll update this article once I've put more riding time into them though (Image credit: Rich Owen)


Aside from fitting iffy laces, Fox have done a really excellent job with the Union Flat shoes. They perform extremely well in all conditions making them some of the best trail MTB shoes around – and are sturdy enough for full gravity use too.

For more on the Fox shoes, see our Five Ten Freerider Pro vs Fox Union Flat head-to-head article.

Tech specs: Fox Union Flat shoes

  • Price: $149.95 / £129.99 / €149.99
  • Sizing: 37 to 47 EU
  • Weight: 838g (size 44 EU tested)
  • Colors: Gray, Red, Black, Olive Green, Mocha Brown
  • Materials: TPU, EVA, rubber
Richard Owen
Editor, Bike Perfect

Rich is the editor of the team. He has worked as a print and internet journalist for over 24 years and has been riding mountain bikes for over 30. Rich mostly likes hitting flowy yet technical trails that point downhill. A jack of many trades, he has competed in cross-country, enduro and long distance MTB races. A resident of North Devon, Rich can mostly be found pedaling furiously around his local trails, or slightly further afield in the Quantocks, the Mendips or Exmoor. 

Current rides: Merida One-Forty 6000, Banshee Paradox

Height: 175cm

Weight: 68kg