Arc'teryx Cormac Shorts
The Arc'teryx Cormac Shorts weigh 150g and use Diem 100% polyester fabric with mechanical stretch for trail running. The 7-inch inseam hits my maximum length for running shorts, and the built-in boxer liner prevents chafing on long efforts. A back-zippered pocket secures keys or a card, and reflective details on the back enhance visibility for early morning runs.
The Diem fabric breathes well and dries fast after stream crossings or heavy sweat. I've run these through Texas summers, where breathability matters more than anything else. The mechanical stretch allows a full range of motion on steep climbs without any binding.
Diem Polyester and Construction Details
The Diem polyester weighs less than cotton-blend alternatives while wicking moisture more effectively. The fabric resists holding odor across multi-day trips, though not as well as merino. The mechanical stretch comes from the weave pattern rather than elastane, which improves durability over time.
Arc'teryx designed the hinged construction for unrestricted leg movement. The regular fit sits comfortably without excess material that flaps during fast efforts. The elasticized drawstring waist adjusts mid-run easily without requiring a full stop.
How Do the Arc'teryx Cormac Shorts Fit?
The fit runs true to Arc'teryx sizing. At just over 6 feet and 165 pounds, I wear a size M with room for the built-in liner to sit comfortably. The 7-inch inseam provides coverage without restricting stride length.
The built-in boxer liner runs slightly snug on me, but prevents chafing effectively. The low-profile seams eliminate hot spots on long runs. Some runners prefer liner-free shorts for cooler temps or different underwear preferences. The Cormac commits you to the integrated liner approach.
Trail Performance and Quick Drying
The lightweight construction shines on technical singletrack where heavy shorts would hold you back. The Diem fabric sheds water quickly after creek crossings and dries within minutes on warm days. The stretch accommodates high steps over roots and rocks without binding at the hip.
The back zippered pocket securely holds a car key or credit card. It's not big enough for a phone, so I carry that in a vest or handheld. The reflective blades on the back are subtle but functional for pre-dawn starts when visibility matters.
The 7-Inch Inseam and Liner Trade-Offs
The 7-inch inseam is longer than many runners prefer. For faster efforts where shorter shorts reduce weight and heat, the Cormac might feel excessive. Arc'teryx offers other shorts with shorter inseams if that matters to you.
The integrated liner eliminates underwear options. If you prefer compression shorts or commando running, the built-in liner gets in the way. The Patagonia Strider Pro offers similar performance, with a removable liner for added flexibility.
For other running gear, see the Cormac Crew Neck LS and Norvan LD3. The Gamma LW Shorts work better for hiking, where the liner isn't needed.