This. There have been a couple of times where I had mechanical issues which prevented me from riding that I've had to bring the bike on the subway with me. I got on the very last car and there was PLENTY of room. The M23 is a fantastic crosstown bus whereas the M42, M34, and M14 are all atrocious. I also take the 2nd ave and 1st Ave uptown/downtown buses on occasion and the M72 across the park is always a good one.