Fox Head Union 2023 Mountain Bike Review

Fox Head Union 2023

Reviews / Shoes

Fox Head 202,667

At a glance

Fox enters the MTB shoe market with their brand new Union shoes. Available for flats as well as clipless (SPD style) pedals with the top of the line model equipped with a double BOA closure system. The sole is designed using the Ultratac™ rubber compound, while the 2-bolt cleat system is designed to have a big amount of adjustment. The shoes come in Black, Red, Grey and a sexy Mocha colorway in size 37 EU - 47 EU. Price: 159.95 GBP / 169.99 EUR

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The product

Fox’s venture into the shoe market is not without research, and it shows. The Union Clipless features a lace closure system combined with a velcro strap on top to really fine tune the fit to your foot.The upper material is a lightweight mesh, coated with a TPU skin for durability and protection from the elements. Perforations on the top and side of the foot give that airflow needed to prevent overheating.

To protect against rock strikes, Fox made a TPU protective toe box. The sole of the shoe is made of their Ultratac material to provide grip and durability. The Nylon infused inner sole is medium stiff to have a good power transfer but still enough comfort on those long days out in the mountains.

The insole is something where a lot of companies save some dollars, but not Fox. Out of the box the Union comes equipped with a low foot arch insole that can be tuned to a high foot arch insole by exchanging part of the insole. A nice feature that makes a lot of difference when it comes to comfort and fit.

Speaking of fit, Fox went with a European sizing chart for their shoes, which makes them unisex compatible. Sizing starts at 37 EU and goes all the way up to 47 EU. To accommodate a perfect fit, the shoes jump half a size from 41 EU to 46 EU. Our pair in size 44 EU put 950 grams on the scale.

Beside the Clipless version we tested, they also offer a flat pedal option with the same features and outsole. For the riders that love the BOA system, there is the Union Boa model which uses a double BOA system to close the shoe instead of the traditional laces and velcro method.

Out on the trail

First thing we noticed is that Fox definitely did their research. The low/high foot arch insole option is a great touch and these shoes are one of the few I could ride without my custom fit insoles. The lacing system is adjustable enough to make the shoes fit whether you have narrow or wider feet and the velcro strap is a classic way to keep the laces out of the way and the shoe from slipping off.

I tested these mainly in winter conditions and was surprised to find them fairly water resistant. Definitely not waterproof, but the moisture and much flowed away from them fairly easily and the upper shoe material is easy to clean. When it gets colder, you do need to wear some thicker socks as they are quite breathable and have little insulation.

The sole is fairly stiff and offers great power transfer to the pedals. You have plenty of adjustment for the cleat no matter if you’re a ‘ball of the foot’ or ‘midfoot’ kind of rider. The space around the cleat is enough to clear out any mud too.

As they are on the stiffer side, they don’t do extremely well on long hike a bike sections. Also the sole itself is not super grippy. There is enough grip on dry and rocky ground, but when it's muddy and greasy, walking back for pictures is a bit tricky. The heel cup has a fantastic fit though, so I experienced zero heel lift or blisters. Because of the materials used, the shoes dry out overnight without any trouble. That’s great because who likes slipping their dry warm feet in cold wet shoes?


Fox doesn't do a bodge job and these Unions are no exception. We love the fit, features and durability of these new shoes and can’t wait to try them in warmer dustier conditions. For the pricing they offer a high end product with great materials and attention to detail in the finish. Fox smashed it out of the park with these shoes, we can definitely recommend. Thumbs up from the IMB Test team!

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This review was in Issue 74 of IMB.

For more information visit Fox Head


By Jarno Hoogland
Jarno's life has revolved around two wheels ever since he swung a leg over his first BMX at age 4. After a BMX and DH racing career, he moved on to work for bike shops, distributors and brands before ending up in the editors seat at IMB. Based in the ultimate testing ground in the Swiss mountains, he runs his guiding operation and makes sure every IMB issue is filled with top notch content.

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