The term is indeed typical to car sales, where a person would come and kick the tyres (thereby trying to show that he is inspecting the car, but actually having no idea what he is doing and usually having no real intent in buying a car). I would assume it has become idiomatic enough to use it when speaking about customers that are "buying" products other than cars, though very rarely. Consider the definition from Wiktionary:
Tyre kicker: A person who pretends to be interested in purchasing an item (especially a car), but who has no intention of buying it.
There might be some other terms synonymous to "tyre kicker" that are more widely used in other spheres, e.g. looky-loo, widely used in real estate to talk about people who go about houses for sale, inspecting then with no intention of buying (and it might be used not only in real estate as well):
A person who seems interested in making a purchase, but whose actual intention is only to browse: