Shimano S-PHYRE SH-TR903 Triathlon Cycling Shoe

Review by Erin Trail

The S-PHYRE SH-TR903 Triathlon Cycling Shoe is the latest and greatest in Shimano’s triathlon cycling line, delivering reliable Shimano design and comfort.  It’s the first multi-sport cycling shoe to earn Shimano’s top tier S-PHYRE designation.

Technical Details

• BOA Fit System with micro-adjustable Li2 BOA dial
• T1 Quick Strap (hook and loop closure) near the shoe opening
• Large heel loop that’s easy to grab during transitions
• Water-resistant synthetic microfiber upper with variable size perforation holes and a pair of mesh panels over the forefoot to boost ventilation and promote quick drying
• Stiff carbon sole and low stack height midsole to maximize power efficiency
• A supportive heel stabilizer that cradles your foot in an optimal power producing position
• A rigid hollow carbon midsole that features water drainage ports to help your feet dry quicker after swim leg
• A barefoot-friendly liner with soft padding promotes comfortable sockless riding

Detailed Review

I have a very old (2013) and very gross pair of Shimano triathlon cycling shoes.  They have been my trusty, comfortable, reliable triathlon shoe, taking me through 4 Ironman races and more 70.3s than I can count. I finally got tired of how gross they looked (and probably smelled) and was excited to try the updated Shimano S-PHYRE SH-TR903 Triathlon Cycling Shoe for my 2025 triathlon season.

My first impression is how sleek they look.  Both colorways (blue or gunmetal) look great and coordinate with a variety of bikes and tri kits. The shiny outer doesn’t seem to scuff or show dirt, even after hundreds of miles of riding.

The toe box is a bit wider than my old Shimano shoes, which is a welcome change.  I often find that my feet swell in hot conditions.  I also have several friends with wide feet and finding a triathlon cycling shoe that accommodates their feet can be a challenge.  I ordered the same size as my old shoes and found that the Shimano S-PHYRE SH-TR903 Triathlon Cycling Shoe fits true to size.

The BOA Fit System with the micro-adjustable BOA Li2 dial is a dream on these shoes.  As mentioned above, my feet have a tendency to swell in the heat.  I did a TON of (intentionally) hot rides in July to prep for a hot 70.3 race.  The BOA Li2 is super easy to loosen as you ride, with a simple reverse clicks on the dial.

The Shimano S-PHYRE SH-TR903 Triathlon Cycling Shoe accommodates a thin customized insole easily.  I have a torn plantar plate and need an insole with a met pad.  These shoes fit my special insoles with zero issues.

Getting the Shimano S-PHYRE SH-TR903 Triathlon Cycling Shoes ride-ready was incredibly simple.  Once I got my cleats positioned and secured, they were good to go.

The T1 Quick Strap feels a bit different than other hook and loop closure systems on cycling shoes.  It hold securely, but also doesn’t seem to snag other fabrics.  It also stay super secure.  I’ve had problems with the shoe strap coming undone if I mis-step while clipping in and I then have to re-secure it on the fly.  The Shimano S-PHYRE SH-TR903 Triathlon Cycling Shoe strap is grippy and reliable.  I also appreciate the black coloring, so any bike grease won’t show.

Testing Conditions:

• About 2 months of weekly “stupid hard” trainer rides, at VO2 MAX
• Longer (40-60 mile) training rides in the heat
• An Olympic distance race and a 70.3 distance race

The best compliment I can pay a shoe is that I really didn’t notice it when I used it.  The Shimano S-PHYRE SH-TR903 Triathlon Cycling Shoe does what it needs to do.  I didn’t notice any discomfort while wearing them during training or racing.  I could also really feel the power transfer from my feet to the pedals, thanks to the super stiff sole.

While transitioning from the swim to the bike and then the bike to the run, the shoes are really easy to put on and take off.  This is an important detail, because every second of racing – even when in transition – counts toward your total finish time.

And have I mentioned how good they look?  Triathletes, road triathlons in particular, are peacocks where we like everything to match and look “pro” while wearing excessive amounts of skin tight spandex.  The design of the Shimano S-PHYRE SH-TR903 Triathlon Cycling Shoe looks sleek, modern, and “pro”.

The Shimano S-PHYRE SH-TR903 Triathlon Cycling Shoe is unisex and comes in sizes Euro 36 to Euro 48.

Erin Trail

Trail Boss of Stoke