The best-documented body of evidence for a cult wheel comes from Gaul, Britain and the Rhineland under Roman rule, and it is worth separating from the much broader class of ancient discs and rayed circles because here there is a corpus rather than an impression.
The material is of three kinds. There are miniature wheels, cast in bronze or lead, a few centimetres across, deposited in their hundreds at sanctuaries, in rivers and in graves, and sometimes worn as pendants. There are stone reliefs and altars showing a god holding or resting on a wheel, frequently a bearded figure otherwise given the attributes of Jupiter. And there is the wheel on the Gundestrup cauldron, where a robed figure and a smaller attendant hold a large spoked wheel between them.
The identification with Taranis rests on a short list of textual evidence. Lucan names Taranis alongside Esus and Teutates as gods to whom the Gauls sacrificed, and a later set of marginal glosses on that passage, the Berne scholia, expands on them. The name is transparently related to a Celtic word for thunder. The link from the thunder god to the wheel monuments is an inference drawn by modern scholars, most systematically by Miranda Green, and it is a reasonable one rather than a documented equation.
That is the caution the archaeology imposes. A spoked circle may be a sun, a thunderbolt, a chariot wheel, or the wheel of a real vehicle depicted as a possession. Sun wheel is a modern interpretive label, and the objects themselves do not say which.