Fox Union BOA clipless shoes review: a revised upper and better impact protection – at a high price

Fox has recently updated its Union BOA clipless shoes, altering some aspects of the upper’s construction and adding a D30 foam insert under the front of the foot to better protect you from impacts.

While I liked the previous version, they took time to break in, needing a good few rides to soften up and become flexible enough for all-day comfort.

Fox has included a new section of ripstop fabric around the heel, ankle and very top of the foot which, although it feels quite similar structurally, adds some breathability.

While padding remains minimal around the ankle, I felt comfortable in the Union BOA clipless shoes within an hour of slipping them on and hitting the trail – quicker than the original Union BOA.

The feel underfoot is still impressive, too, but there’s no denying that performance doesn’t come cheap at £220 / $275.

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Fox Union BOA clipless shoes details

Visually, the new Union BOA clipless shoes don’t look a whole lot different from their predecessors.

While the previous shoes featured a TPU welded upper throughout, the new model uses ripstop fabric around the ankle, heel and across the very top of the foot, including the tongue.

The remainder of the upper is TPU, which is perforated over the toes and on the inside of the foot, just as before, with the same reinforced toe bumper for some added protection.

Fox continues to use the dual Boa Li2 closure dials, although these now tighten a cord, rather than a plastic wire, as was the case on the first version of the shoe.

You still get removable arch supports with Velcro to the underside of the insole. There are two to choose from (high and low), each pair colour-coded with the height and side stamped into them to avoid confusion.

What’s different here, though, is the insoles now feature a section of D30 padding directly under the ball of the foot, spanning up and under most of your toes, to help absorb impacts.

This material is often used in knee and elbow pads because it remains flexible until an impact occurs, before absorbing the blow and hardening up.

The insole then sits on a cushioned surface in a bid to boost comfort further.

Flip the Union BOAs over and you’ll see decent-length cleat slots and broad enough cleat pockets to ensure ample mud clearance either side of the cleats once fitted.

Surrounding the cleat pocket is Fox’s Ultratac rubber treads, with evenly spaced blocks, all of which are the same depth.

My pair of size EU 42s, with Crankbrothers cleats fitted, weigh in at 936g, which is competitive for this type of shoe.

Fox Union BOA clipless shoes performance

Taking tension out of the Boa cords is easy; simply pop the dials upwards and they’ll unspool the cord when you open the shoe out. This makes getting the Union BOAs on incredibly easy.

Perfecting the fit with the Boa dials is simple and, with two dials, you can easily ensure the tension across the top of the shoe is nice and even.

Even when cranked up decently tight, I didn’t suffer any hotspots either side of my feet, and thanks to the broad toebox, neither foot felt cramped or pinched.

With the lowest arch support fitted, the footbed feels quite neutral, which suited my feet well.

Riding with the higher supports fitted, I suffered aching on the inside of my feet after a while.

The padding around the ankle isn’t particularly thick or plush, like that of the Crankbrothers Mallet, for example, but there’s still enough to provide ample cushioning and a comfortable fit.

Overall, the fit feels very secure yet spacious and protective.

Off the bike, there’s enough bend at the toe to allow you to walk fairly naturally, although the Unions are a little stiffer than some, meaning you’ll get some heel lift, especially if you’re scrabbling back up steeper trails.

I fitted spacers underneath my Crankbrothers cleats because the cleat pockets are quite deep.

Even with spacers in place, clipping in doesn’t feel quite as distinct as it can do on other shoes, and it’s worth making sure that if your pedals have pins around the outer cage, winding them lower helps improve the connection.

But having ridden in the originals for quite a while prior to receiving these updated shoes, this was something I was already used to and had no issue with.

There’s also plenty of length on the cleat slots to get your cleats right back towards the midfoot – a position that I find helps to improve bike control and staves off fatigue on longer downhill runs.

The relatively stiff outsole (especially if it's being supported by a cage-style clipless pedal body) ensures you can really get the power down.

There’s no obvious flex with mountain bike pedals such as the Mallet E or Mallet DH. And even when I switched to the much smaller Mallet Trail, flex was minimal.

We’re not talking super-stiff and efficient, carbon-soled and hard-to-walk-in cross-country shoes, but considering these are aimed at trail, enduro and downhill riding, they feel decently efficient when it comes to putting the power down.

Despite that stiffness, the Union BOAs don’t lack feel through their soles, enabling you to get a feel for where the pedal’s mechanism is when you need to get clipped back in.

They don’t feel as flexible or thin as some, but when you get used to the stiffer feel, you soon adjust to the level of feedback coming up through the soles of the Union BOAs.

On rougher trails, the broad, well-cushioned footbed really comes into its own.

The Union Boas may not offer as much feel through the soles as some shoes, but this works in their favour when you’re battering down chunky tracks because they feel as though they shield the bottoms of your feet a little more from the constant abuse they’re being subjected to.

Should you unclip and struggle to get your cleat back into the mechanism, there’s sufficient traction from the Ultratac rubber outsole, meaning things don’t feel sketchy.

Fox Union BOA clipless shoes bottom line

Overall, the Fox Union BOA clipless shoes feel comfortable and protective, despite the minimal padding.

The dual Boa dial makes life easier, especially when getting them on and off when they’re wet and muddy.

While the stiffness through the sole means they don’t offer quite as much flex or feedback through the pedals as some, you quickly get used to this, and the plus here is they cushion your feet well on rougher terrain.

It’s hard to ignore the pricing because they’re certainly not cheap, but they perform well and should last.