Gerry's tire in the city. They mounted and balanced mine with quick turn around. They are aware that some people swap tires for winter and summer. All the other shops in Baltimore are ghetto af or wont do it. If you plan on waiting their waiting area is pretty much only like 4 chairs. You could walk down to Attman's or Lenny's though for a quick bite.
http://gerrystires.com/
39 S Central Ave, Baltimore, MD 21202