big wheel vs big deal

big wheel and big deal both are nouns.

Word	Noun	Adjective	Verb	Adverb
big wheel	Yes	No	No	No
big deal	Yes	No	No	No

As nouns, big wheel and big deal are synonyms defined as:

Other synonyms of big wheel include big cheese, big enchilada, big fish, big gun, big shot, head honcho.

big wheel (noun)	big deal (noun)
an important influential person	anything of great importance or consequence
	an important influential person