Way too high for urban. Especially NYC. You got a deathwish? You looking to have double knee replacement in your early 30s?

My gearing is 48x15 fixed, but I live rural and most of my rides are traffic light/stop sign free and rolling hills. For me it's a fitness thing. The only strain is getting started, but once I'm up to speed it's 90-120 rpm consistantly. Can't imagine trying to take off from traffic lights and navigating NYC w/the gearing in your post. Like others have suggested try putting a 17, 18 or 19t cog w/t 48. Makes much more sense for your environment and terrain.