Downer-Groves were motorcycles produced from 1920 to 1922.
They were designed and constructed by a compulsive inventor named Cecil Downer-Groves at his home/workshop in Croydon, Surrey. Intended for use by himself and his family, the first of his two machines was a motorised cycle fitted with a 1¾hp two-stroke engine that was mounted inside the frame diamond of a gents' safety-cycle. The second machine was a motorised tandem. This was similar to the later Autocycle, but more substantial and elongated to provide seating for two. Both machines survived for many years.