Hollow cylindrical geometries represent critical and commonly encountered geometry in spacecraft systems appearing in tubes, conduits, wire housing, and structural elements. Understanding flame spread over hollow cylindrical fuels is highly relevant for the application of space fire safety. This work presents experimental study on opposed flow flame spread over thin hollow cylindrical cellulosic fuel of diameters varying from 10 to 49 mm in microgravity environment. To understand the effect of flow on flame spread, experiments are conducted in low convective opposed flow conditions ranging from 10 to 30 cm/s for different hollow cylindrical fuel diameters at oxygen concentration of 21% and 1 atm pressure. In the microgravity environment, the flame length and the flame spread rate are seen to increase with increase in hollow cylindrical fuel diameter over the flow range studied here. The flame spread rate exhibited a non-monotonic trend with flow speed, for flow of large diameter whereas a monotonic increasing trend is noted for small diameters. A simplified analysis is carried out to arrive at an expression for flame spread rate over thin hollow cylindrical fuels. The analysis shows that the radiation exchange from the hot char to the inner surface of hollow virgin fuel (solid to solid radiation) and overall equivalence ratio dictates flame spread rate trend with fuel diameter. This study addresses the existing knowledge gap on flame propagation along hollow cylindrical surfaces, where strong flame interaction and oxygen starvation are competing each other inside cylinder. This advances the fundamental understanding of flame spread in complex geometries. These insights are particularly valuable for identifying atypical fire behaviors in space environments.