Cross frame or diamond frame? This 1889-1890 model Singer is really something in between.
The 1891 catalogue of Singer shows the then new steering lock, inclusing a version that could be fitted to older models. It's hardly visible, but this Singer has one of those steering locks, that was attached a few years after the bicycle has been sold. Look at the last illustration, coming from the 1891 catalogue.
And the longer you look at this Royal Singer, the more beautiful it gets. Look at the front suspension system, and, as a consequence, the rear wheel band brake. The adjustable bracket, the chainwheel, the lugs. This bike is special in every detail and the Musee d' Art et d' Industrie in St. Etienne is lucky to have one in their collection. Original paint and even a nice transfer on the (ball bearing) head.
The front suspension was introduced in 1890, but could be fitted to older models. So, as long as we do not know the serial number of this bicycle, it's hard to say if this is the 1889 or 1890 version.
The 1891 catalogue of Singer shows the then new steering lock, inclusing a version that could be fitted to older models. It's hardly visible, but this Singer has one of those steering locks, that was attached a few years after the bicycle has been sold. Look at the last illustration, coming from the 1891 catalogue.