bike rack vs bicycle rack

bike rack and bicycle rack both are nouns.

Word	Noun	Adjective	Verb	Adverb
bike rack	Yes	No	No	No
bicycle rack	Yes	No	No	No

As nouns, bike rack and bicycle rack are synonyms defined as:

Other synonyms of bike rack include bicycle parking rack, bicycle stand, bike parking rack, bike stand.

bike rack (noun)	bicycle rack (noun)
a rack for parking bicycles	a rack for parking bicycles