A lot of special or experimental frames have been built. Double tubing was supposed to add strength, but in reality it only added weight.
These were almost experimental models, but some were very succesful !
| Rudge, c 1890|| Rudge c. 1891-92|| HHC model F c. 1889|
| Victor Model C 1892|| Humber no.5 1889|| Terrot|
| Columbia model 27, 1893||Columbia model 39, 1893|| Sparkbrook no.1 c. 1888|
| Rochet modele B|| Hurtu c 1890|