Sort of biker regularly wearing glasses (7)
I believe the answer is:
species
'sort' is the definition.
(I know that species is a type of sort)
'biker regularly wearing glasses' is the wordplay.
'regularly' indicates alternate letters (regularly take one letter, leave next etc.).
'wearing' indicates putting letters inside.
'glasses' becomes 'specs' (spectacles).
The alternating letters of 'biker' are 'ie'.
'ie' put within 'specs' is 'SPECIES'.
'of' acts as a link.
(Other definitions for species that I've seen before include "Breed or genus" , "Groups of related plants or animals" , "Taxonomic group capable of interbreeding" , "Group of organisms" , "Taxonomic grouping" .)