Nothing is seen of the Tricycle conversion until this advert in cycling late 1935 and assumed to be for sale in 1936. It is not listed in any catalogue until 1937. This was a conversion rather than a purpose built tricycle like the Racing Tricycle sold by FH.

Then the late 1936 sheet (right) shows a Holdsworth ‘Solid-Drive Tricycle‘. it also seems Abingdon Axle Tricycles were also available.

1937 Catalogue

1939 Catalogue

Bill Rann, who was forman and the mechnical brains at FH Grubb join Holdworth, also as forman, early 1935. He designed the Tricycle Conversion Set pre March 1936 having previoulsy design the Rann kiddie trailer for Grubb.

1951 Catalogue

Initially racers wouldn’t use it because it increased the wheelbase, so sometime after 1939 Bill redesigned it in a way that shortened the wheelbase. It seems to be avaliable unchanged until 1972 although not always listed.

1972 Catalogue