FlexFitbyJohn | From Bike Fitter to Internet Tire Testing Authority | John Karrasch | The Stable Cyclist Podcast

This week, JP sits down with John Karrasch, better known as FlexFitByJohn, whose gravel tire rolling resistance and speed tests have taken the cycling world by storm. What started as a behind-the-scenes bike fitting career in Birmingham, Alabama turned into a meteoric rise as John became the go-to resource for accurate, data-driven tire performance testing. In this episode, John talks about how his meticulous work with the Chung method built trust across the gravel community, eventually landing him on the Escape Collective podcast with Ronan McLaughlin and establishing him as one of the most respected voices in modern cycling tech. JP and John go deeper into what it feels like to transition from relative obscurity to becoming a widely recognized figure in the sport. They talk about imposter syndrome, validation from Robert Chung himself, and how to stay grounded when your identity is shifting and your work suddenly reaches thousands of riders. This episode blends cycling science, personal growth, and the human side of going viral — a must-listen for anyone who loves gear, gravel, or a good story of unexpected success. If you’d like to ask JP a question for an upcoming Ask JP Anything episode, send him a DM on instagram @thestablecyclist or send an email to [email protected] The companies supporting JP and this channel: Maplelag Resort - https://www.maplelag.com/ Wark's Cycling Services - https://www.warkscyclingservices.com/ Gulo Composites - https://gulocomposites.com/ Flow Formulas - https://flowformulas.com/discount/JOHNPETER15 Wahoo Fitness - https://www.wahoofitness.com Dawn to Dusk - https://www.https://dawntodusk.bike/ Owl City Cycles - https://www.owlcitycycles.com The Black Bibs - https://www.theblackbibs.com Ignition Coach Co. - https://www.ignitioncoachco.com/ Mental Health Advocacy - Go4Graham - https://www.go4graham.org/ Resources: 988 Lifeline: https://988lifeline.org/ International Bipolar Foundation: https://ibpf.org/ National Association for Mental Illness: https://www.nami.org/ #GravelCycling #ChungMethod #StableCyclistPodcast