This paper presents Transit for All (TFA), a spatial computing framework for expanding bike sharing systems (BSSs) to address the challenges of limited public transportation access for low-income and minority communities in densely populated cities like New York City. TFA consists of three components. First, it uses local representation learning, which integrates diverse spatial data, to predict bike sharing demand at new station locations. Second, it performs a comprehensive public transportation accessibility assessment using a novel Weighted Public Transportation Accessibility Level (wPTAL), which combines predicted bike sharing demand with existing public transportation accessibility metrics. Third, it provides strategic recommendations for new bike station placement, considering potential ridership and equity gains. Using New York City as a case study, it identifies public transportation access gaps that disproportionately impact low-income and minority communities and demonstrates that strategically placing new stations based on wPTAL can significantly reduce public transportation accessibility inequities associated with economic and demographic factors.