Looks can be deceiving, even when it comes to clothing.  See that black shirt?  From a performance standpoint, it’s actually white.  It’s also stylish and comfortable for trail running, and ideally suited to long hours in the sun. Here’s my take on the Pearl Izumi Infinity In-R-Cool SS shirt.

Pearl Izumi Infinity In-R-Cool SS Shirt Features:

  • ELITE Transfer fabric pulls moisture from skin
  • In-R-Cool technology for temperature regulation
  • Direct-Vent mesh ventilation panels
  • Semi-fitted cut
  • Reflective accents for visibility
  • UPF 50+ protection
  • MSRP $45

Pearl Izumi Infinity Shirt Review

The Infinity shirt introduces Pearl Izumi’s new fabric technology for 2011:  In-R-Cool, which uses reflective elements to deflect the sun’s rays just as a solid white shirt would.  White gear is all the rage in the tri community; with In-R-Cool fabric, you get the cooling effect of white apparel without looking like you’re crossing the Sahara.  This is a hard performance feature to measure objectively, but I’ve worn my dark gray shirt on hot mid-day runs (Hooray, California!), and it’s hard to tell the difference compared to wearing a light-colored top.

The main panels of the Infinity are constructed from ELITE Transfer polyester, which places a very comfortable layer against the skin and utilizes one-way transfer design to pull moisture away from the skin, further enhancing skin cooling as you sweat.  Extensive ventilation is provided by large mesh panels stretching from the shoulder blades down the side of the torso, composed of 92% polyester and 8% elastene for freedom of movement.  An elasticized webbing connects the mesh areas across the shoulder blades, and gives you a bit of a Spider-Man vibe.


Torso cut is semi-fitted, giving you just enough room for full range of motion without feeling baggy.  Its length is long enough to stay comfortably tucked into your shorts even when wearing a waist pack.  I’ve found the Infinity to ride very comfortably, even with multi-hour runs on the trail.  Its fabric is extremely soft against the skin, without any hot spots or chafing, and its ventilation and moisture management work as advertised.  Pearl Izumi bills this as the ultimate lightweight hot weather running top, and from my experience it’s a hard claim to argue.

Mesh ventilation across shoulder blades; elastic web in between

Good Infinity

  • Outstanding temperature regulation from Transfer fabric and In-R-Cool technology
  • Great ventilation from mesh panels
  • Super comfortable feel against skin

Bad Infinity

  • Maybe the spider-web look?  It might not be for everyone.  Yes, I’m grasping at straws a bit here.

Bottom Line: Pearl Izumi Infinity Shirt

With ideal comfort and superior performance features, the Pearl Izumi Infinity In-R-Cool looks to be one of the top trail running tops for the warm days of spring and summer.

Buy Now: Pearl Izumi Shirts at REI.com

About Author

Donald is a physical therapist, ultrarunner, barefoot aficionado, and father of three with more than 20 years of experience in endurance sports. When he's not training for ultramarathons, he enjoys hiking or slacklining with his family in Monterey County, CA.

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