Shimano RX8 gravel shoe review: a lightweight, racy off-road option

Shimano has made cycling shoes for a long time and it would be fair to say that the Japansee giant knows a thing or two about manufacturing cycling products. The brand boasts a comprehensive range across all genres and launched the shoe you see here off the back of its gravel-specific component range, GRX. 

Some might say that Shimano took its time to jump on the gravel bandwagon - despite it claiming GRX was the first gravel-specific groupset - but once Shimano entered the gravel scene, it ran with the idea. So just how good are the RX8 shoes and where do they sit among the best gravel bike shoes?    

Design and aesthetics 

Starting with the outer sole, the RX8 has a full-length carbon sole that is rated 10 (out of 11 for the off-road range) for stiffness. The tread grip is minimal and spaced out and deep enough to protect the cleat. These have been designed to pair perfectly with the latest Shimano M9100 XTR or M8100 XT pedals and will be compatible with all two-bolt SPD standard cleats and pedals. 

Shimano specced a quality inner sole that is comfortable and boasts Siladur lining to keep your shoes smelling fresher even if your gravel adventure is on the hottest days of summer. Shimano also ships the RX8 with an additional arch support in the box to perfect the fit and add to the quality feel of these shoes. The top of the tongue and the collar contact areas have been well thought out and are supple and soft. Adding to the comfort is the snug and supportive heel cup that aids pedaling efficiency.     

The upper is made from synthetic leather and it has been cleverly designed to be one piece. There is plenty of ventilation across the top of the toes and down the outside of the foot. On the subject of toes, the front of the shoe or toe box is nice and roomy, giving you some wiggle space which is welcomed on long days in the saddle. The toe and heel feature, an albeit minimal, TPU protective bumper to save your hooves from flying debris in the areas most at risk. The one-piece upper comfortably wraps around your foot that is secured and fastened using the combination of a single Boa dial and also a velcro strap at the front of the shoe. 

If you are a baggy shorts and t-shirt kind of gravel rider who is more about the party pace rather than all-out performance and gravel racing, these might not be your cup of tea, especially in this bronze colorway. There is a more subtle all-black version and a silver option, too. Shimano also makes the women's version - the RX8W - available in navy blue and bright yellow designs. If you have a wider foot, Shimano offers a wide option that is only available in the black colorway.

Performance

When you first slip your feet in and twist the Boa dial you will notice how snug the RX8 and its wrap-around design hold your feet like a burrito. They offer an even hold that creates no uncomfortable pinching and the tongue doesn't ruffle up. I have been wearing a laced gravel shoe for the past few months and in comparison, this design gives a far more consistent and even fit. Shimano says “Comfort is critical for ultra-endurance gravel racing events and the RX8 delivers a glove-like fit“ and I genuinely believe it has achieved this. 

The next thing you will notice is just how stiff the sole feels when walking. Just a short walk to my bike and it is immediately evident that the RX8 shoes are not made for rides that might include extended efforts off the bike on foot. It is clear from the first forceful push on the pedals that this stiff sole is focused on delivering power through the pedals.

The sole has a shallow and narrow tread width and with no provision for toe studs, these are not exactly suited to mud and slippery conditions underfoot. The narrow tread made me feel quite nervous walking, let alone clambering up slopes in these shoes with fear of rolling off the side and potentially painfully tweaking my ankle.

This offering from Shimano is not just a mountain bike shoe that has been put on a serious diet. This is a ground-up fresh take on a gravel shoe design with a clear nod to the rapidly developing race scene. The shoe is light, the RX8 nudged my scales at a feathery 576g for a pair (without cleats) in size 43. 

With the period of testing being solely in the winter months, the synthetic leather paired with the one-piece design does a good job of fending off the worst of the mud and water. The sizing worked perfectly for my feet and I really like the softer contact points around the collar and the top of the tongue, especially on the extended rides. 

Verdict

The Shimano RX8 is definitely more of a race slipper. It’s best suited to gravel riders from a road background looking for the stiffer sole and a design leaning more towards pedaling efficiency and power transfer. The stiff sole delivers power without feeling harsh on long, rough rides and the weight at 265g is one of the lowest in the gravel shoe market.

With the ratio of time on the bike versus the amount of time you would be expecting to be walking on a gravel ride I can see why Shimano has made the RX8 closer to a road shoe than a mountain bike design, but I would still prefer to see a wider tread design on the sole. That said, the design is rugged enough and comfortable to wear on the bike for those long gravel races. 

If you are less of a racer and more of a bikepacking rider who's looking for a performance shoe but is still likely to spend a significant time off the bike, then Shimano's XC range might be better suited.

Tech Specs: Shimano RX8 gravel shoe

• Colors: Bronze, Silver, Black
• Retention: 1 Boa (IP1), 1-strap
• Uppers: Synthetic leather
• Outsole: Carbon fiber composite + TPU
• Weight: 265g Men’s size 44
• Sizing: Standard: 38-50 Wide: 38-48
• Price: $260 / £219 / €229.99