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Review: Shimano S-Phyre finds room to improve with XC903 series

Changes add up to a substantial improvement over previous generation and the competition.

How do you improve on one of the best regarded cross country shoes on the market? With the new S-Phyre XC903, Shimano proves small changes can add up to create significant improvement.

The result is a lightweight shoe that stands apart, even among high-end cross country race shoes. Here’s a rundown of the changes, features and our review of the new Shimano S-Phyre XC903.

XC903: what’s new?

While the new S-Phyre looks quite similar to what came before, there are some important differences. And some smaller ones, too. The main changes are to the upper and to heel support. Some smaller, but very nice changes include a Boa shield and changes to the lacing system.

The upper on the XC-903 is now made of the same breathable surround-wrapping microfibre leather that the road RC-903 is. The change is designed to improve comfort so that, in turn, you can improve power transfer. The microfibre leather is more elastic and more supple. That allows the shoes to be worn tighter for longer without creating discomfort or hot spots.

Shimano also borrows the anti-twist heel stabilization feature from its S-Phyre RC903 road shoe. This keeps the foot solidly in place during accelerations and efforts, but also through the various shifts in balance that come from trail riding.

S-Phyres feature two low-profile, dual-direction BOA Li2 closure dials. The allow for easy fit adjustments while riding. New for the 903 series is a small shield below the lower BOA dial to protect it from damage or accidental release on the trails. Shimano also changes most of the Boa lace cable guides from plastic to mesh. The main guide remains plastic, but the rest shift to mesh to cut weight, add comfort and, frankly, to look nicer.

Shimano uses the same lightweight carbon fibre midsole (Stiffness 11 of 12 on Shimano’s arbitrary scale) and Ultread XC lightweight rubber sole as the previous generation. And there’s still the ability to run toe spikes with one very aggressive set included.

Review: Shimano S-Phyre XC903

The S-Phyre’s arrived at our testing shack at about the same time as another new high-end pair of lightweight XC shoes. This was extra convenient for us, as it allowed for a direct comparison between new shoes – not a new pair and a worn in/worn out pair. The shoes were initially comparable in comfort, both fitting and on short rides to break them in. This could have been trouble as both are expensive but the Shimano’s are over $100 more expensive. But the S-Phyres quickly pulled ahead. Here’s why.

The change to the new microfibre leather upper allows for impressive fit, especially on longer or more challenging rides. It didn’t initially feel as cool or light as the other pair (though a scale confirmed the S-Phyre’s are actually few grams lighter). Shimano’s heel lock also took about half a ride to bed in and feel comfortable. After that, it never rubbed the wrong way again.

Better fit defeats fatigue

But, as I started to do longer rides and on more trail than gravel, the S-Phyre’s stood out. They remained comfortable, with no hot spots or pressure points, even on long rides, through hard efforts and through a B.C. heat wave. Only on the longest descents did I start to feel the same sort of ache that other lightweight shoes are prone to much earlier.

This is likely due to the combination of the heel lock, the new upper and, in my opinion, the long wire lace attached to the lower Boa dial. The latter allows for more micro micro-adjustments than the competitors shoe using the same Li2 dial and a shorter wire. This makes it easier to dial in fit while on the move. The main support, though, comes from the upper and the heel lock. Mountain biking requires constant weight and balance adjustments, especially while descending on pinner short travel race bikes.

With S-Phyre 903, I was able to comfortably lock in my feet without creating hot spots, so that I had the support from the shoe while twisting and turning on the pedals. Even long, standing efforts on descents felt solid. With S-Phyre, it felt like my feet were having to do less work to stay entered on the shoe.

It can be tricky to accurately compare different equipment between rides. And S-Phyres are still very expensive. So, to make a more concrete comparison, I did several rides wearing one Shimano and one Canyon (switching which foot wore which brand, of course). Every time, it was the Shimano that was still comfortable, still solid when the other started to have hot-spots or started to ache.

Tiny changes

Then there’s the Boa shield for the lower dial. This is a simple solution to a problem most riders who have used a shoe with Boa dials have faced at some point. You rarely clip and loosen a Boa dial when it’s a convenient time to reach down and tighten it. It’s always when you’re pushing hard enough that you’re brushing up against trail side shrubbery. After spending a week at a race chasing riders that are, to be blunt, much better than I am, and testing the durability of the Boa shield and the new upper material, both came away looking great. I’m so glad Shimano “spent” an extra gram or two to include this feature.

Last word review: Shimano S-Phyre XC903

This is, at this point, a lot of digital ink to spill on a pair of shoes. But getting into a pair of S-Phyres requires spilling a hefty chunk of change. The XC903 are $630 in Canada (USD 450.00). That’s steep. But, if you can manage that entry fee, Shimano at least matches the price with performance. Some of these features are also trickling down to the brands 7-series and 5-series shoes, at least on the road. Hopefully new dirt slippers will follow soon.

Shimano offers the S-Phyre XC903 in standard and wide fit. XC-903 comes in sizes 38-48 with half sizes from 41.5-46.5. XC903 Wide comes in sizes 40-48, with no half-sizes.