biker vs bicycler

biker and bicycler both are nouns.

Word	Noun	Adjective	Verb	Adverb
biker	Yes	No	No	No
bicycler	Yes	No	No	No

As nouns, biker and bicycler are synonyms defined as:

Other synonyms of biker include bicyclist, cyclist, wheeler.

biker (noun)	bicycler (noun)
a person who rides a bicycle	a person who rides a bicycle