car tire vs auto tire

car tire and auto tire both are nouns.

Word	Noun	Adjective	Verb	Adverb
car tire	Yes	No	No	No
auto tire	Yes	No	No	No

As nouns, car tire and auto tire are synonyms defined as:

car tire and auto tire: a tire consisting of a rubber ring around the rim of an automobile wheel

Other synonyms of car tire include automobile tire, rubber tire.

car tire (noun)	auto tire (noun)
a tire consisting of a rubber ring around the rim of an automobile wheel	a tire consisting of a rubber ring around the rim of an automobile wheel