Is This the Most Stable Gravel Aero Wheel Ever Made? | Interview with Mark Hopkins from CSixx

We sit down with Mark Hopkins the founder of CSixx to find out how his 65mm deep gravel wheels became the biggest surprise in the insane crosswinds on our wheel test. From rim shape and aerodynamics to internal width, spoke choice and real-world durability, Mark breaks down the design philosophy behind these seriously deep gravel wheels. We also talk about why a deeper wheel can still feel incredibly stable in brutal Cape Town crosswinds—and whether the 65mm is the right choice for a 517km gravel race. Is deeper really faster, or have we completely lost our minds chasing aero gains? 01:01 Meet Mark from C6 03:04 Where Does a Carbon Wheel Begin? 04:34 Why Internal Rim Width Matters 05:43 Aerodynamics & Tire Harmony 07:53 Why Go 65mm Deep? 09:05 The Secret to Crosswind Stability 11:55 Spokes, Compliance & Gravel Durability 13:15 Why External Nipples Matter 15:30 Hub Engagement & Reliability 17:54 Is the 65mm Wheel Right for Gravelburn? \# === LISTEN ON THE GO =========================== Spotify: https://open.spotify.com/show/5GselFmeym7YgYXtcyPUXU Apple Podcasts: https://podcasts.apple.com/us/podcast/active-hobo/id1846864699 \# === FOLLOW ACTIVE HOBO ========================= https://linktr.ee/theactivehobo \# === PARTNER LINKS =================================== Doolhof Wine Estate https://doolhof.com 🔗 Code: ActiveHobo (20% off wines) RH 77 🔗 https://rh77.co.za Code: THEACTIVEHOBO30 (30% off, first 10 users) 226ERS 🔗 https://226ers.co.za/ Code: ActiveHobo (10% off) SCICON 🔗 https://theactivehobo.short.gy/sciconsports-discount (URL and 10% Discount code link) East City Cycles 🔗 https://eastcitycycles.com/ Gear Change Bicycle Store 🔗 https://gearchange.co.za/ \# === THE CREW =================================== Dave @davlewjenkins \# === MORE FROM ACTIVE HOBO ====================== Latest episode: https://youtu.be/vSnCZ6pTguQ?si=4hvAobdbQznnyw10 Full podcast playlist: https://www.youtube.com/playlist?list=PLc2XIoaiAXafwoZykJM-jg6HnrLkWlJXH Related episode: https://youtu.be/mgogDtiB\_vg?si=RBaUt8VItbQisdTd \# === WORK WITH US =============================== Sponsorships & collabs: david@activehobo.com Send a question for the show: noah@activehobo.com #ActiveHobo #CyclingPodcast #SouthAfricanCycling #gravelbike #envewheels #zipp #carbonwheels #gravelwheelreview #ENVEGSES4.5 #Csixx65 #Zipp303XPLRSW #RovalTerraCL