Whether TRON Lightcycle / Run at Magic Kingdom is "Pooh-friendly" (accessible for larger-bodied guests) is a common concern because of its unique "bike-style" ride vehicle. The standard seating requires you to lean forward and have a restraint secure your back and calves, which can be restrictive for guests with larger midsections, broad shoulders, or thick calves. To be supportive and direct: the standard cycles are not universally accommodating, and many guests find the leg restraints difficult to lock. However, Disney has integrated a "LightRunner" vehicle (a traditional upright seat with a lap bar) at the back of some trains. If you are worried about fitting, you can ask a Cast Member for the "accessible seat," which provides a much more generous and comfortable fit for "Pooh-sized" individuals or those with mobility issues. A grounded tip is to use the test seat located outside the attraction entrance to check your fit privately before joining the queue. This ensures you can enjoy the "grid" without any unexpected discomfort or the stress of a "no-go" at the loading platform.