We Tested the Clipless Shoes That Won the DH World Cup—Here's What We Found

The clipless MTB shoe market is saturated with super-great options from Shimano, Specialized, Crankbrothers, FiveTen, and more. So what makes the Fox Racing Union BOA worth considering? After testing these shoes against competitors at similar price points, the Union BOA stands out for three reasons: the dual BOA Fit System offers genuinely superior fit adjustment, the molded toe box delivers a sense of security without sacrificing fit, and the D3O insoles provide excellent arch support. Are they perfect? Not quite. Are they worth checking out if you're shopping for premium clipless shoes? Absolutely.

Yeah, Jackson Goldstone dominated the 2025 UCI DH World Cup in these shoes, but I’m no World Cup-level athlete, so how do these high-end shoes mesh into the life of the average rider? Spoiler alert, they won't make you anywhere near as fast as Goldstone.

Fox Racing is new to the footwear scene but a long-standing icon in MTB protection and apparel, so seeing the brand branch out into shoes was exciting. The Union BOA shoes not only look great, but also feature a dual BOA Fit System, D3O insole, Ultratac™ rubber sole, reinforced toe box, and swappable arch supports, making for a really impressive offering that proves the beauty is more than just skin deep.

Initial Impressions

I'm a big fan of white shoes, so the fact that these were available in a (mostly) white colorway already got them off on the right foot. Still, after a lot of time riding, hiking in snow, and walking around a flower shop for some mums, these decidedly gravity-oriented MTB shoes have me impressed.

Fox Union BOA Details

MSRP: $274.95

• Flat and Clipless Variants
• Molded Toe Box
• Dual Li2 BOA Fit System Closure
• Welded TPU/Ripstop Upper
• Ultratac™ Sole
• D3O Footbed

I’m blessed with a pretty average foot shape, which means I get along with most shoes on the market and don’t need to hunt for a “wide” variant, and good thing too, since Fox does not make the Union BOA in a wider last. The last is pretty roomy, however, so if you do typically need a wider shoe, these might fit the bill, but I wouldn’t count on them being ideal.

In terms of construction, the Union BOA uses a welded TPU/ripstop upper that comprises the majority of the shoe; this covers a molded toe box that helps protect the little piggies from rock strikes out on the trail. The ankle on the Union BOA is a pretty traditional height, but there is a Union BOA All-Weather option with a taller cuff for those looking for more coverage in the winter; this version also only uses a single BOA and has a waterproof upper.

The sole isn’t terribly soft, which is comforting for longevity, as softer rubber can degrade much more quickly if you’re hiking a lot or use clipless pedals with pins. It’s not that hard, either, and when riding pedals with pins, the contact between said pins and the sole feels very secure without showing signs of wear too quickly. 

First Ride

Out of the box, I swapped the arch supports to the higher option and noticed the D3O insert in the insole, a material that many brands are utilizing to help reduce vibration and soften impact at the contact points on the bike. This is the first shoe I’ve used that implements this tech into the insole, and so far, I haven’t noticed any significant differences, but maybe that's the point? Marginal comfort improvements can be tricky to measure, especially when the trails are so soft this time of year. 

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The dual BOA Fit System dials on the shoes are the latest from BOA in the form of the Li2. These are slightly smaller than previous generations and use a 2-way ratchet that lets you tighten and loosen the dials in small increments with ease, as well as open them fully when kitting up and taking them off. In terms of layout, the dials' lacing is super basic, and there's no complicated overlaps or crossings of the cables, making the Union BOA fit very similarly to a regular lace closure - kudos for that.

Construction & Pedal Compatibility

Initially, I found the uppers noticeably stiffer out of the box than those of other shoes in the same category, which worried me that they would require a much longer break-in time. However, after some messing with the BOA Fit System and loosening the uppermost dial quite a bit, I was able to get more flex from the tongue yet retain heel retention. I only needed to take the approach in the first couple of rides, and after consistent wear, the upper began to relax and accommodate the ankle flex that I was demanding. 

The cleat-positioning rails are another standout feature of the Union BOA, offering much more adjustability than many other clipless mountain bike shoes. There is a lot of room to scoot the cleat all the way forward (I don’t know anyone who does this, though), and ample space to get the cleat really far back, for more of a mid-foot position. The lateral positioning is also generous, and the cutout leaves plenty of space for various cleat standards and pedal options, as well as fine-tuning Q-factor. From what I’ve found, there isn’t a two-bolt cleat or pedal option that the Fox Union BOA doesn’t play nice with.

Pros & Cons