Stepping into the indoor trainer environment, this time we use a smartphone camera and AI algorithms to test whether it can find the most suitable cockpit setup for a cyclist. The test specifically brings out a pre-configured road bike and invites a roommate with a completely different body type to mount the trainer and pedal, deliberately challenging whether the app can identify geometric discrepancies. The camera captures detailed lateral shots of dynamic pedaling, and the software automatically recognizes the movement angles of the hip, knee, and ankle joints, analyzing in real time the appropriateness of inseam, saddle height, fore-aft position, and cockpit length. The video also compares the AI results with traditional manual measurements one by one, offering practical reference value for cyclists who want to fine-tune their riding position at home or are curious about the accuracy of tech-based fitting.