How do you tell forging from casting?
How do you tell a forged wheel from a cast one?
In fact there are only a few indirect signs you can use to tell forged and cast wheels apart by eye in a shop. There is no way to say for certain whether you are being offered a forging or a casting without sophisticated tests and equipment. So you will have to rely on your own logic, and on the seller’s competence and honesty.
So, the most common “folk” way to tell them apart is by the markings. For mass-produced wheels, the service markings, which are mostly stamped on the inner surfaces of the wheels, are raised (cast in) on a cast wheel and recessed (pressed in) on a forged one. In most cases this way of telling them apart works (it comes from the manufacturing technology of both types of wheel), but there are quite a few exceptions to this rule (in both directions), so it is not worth relying on this sign alone. The exceptions are especially common with forged wheels made to order by styling studios and serious manufacturers.
In the manufacturer’s specifications, forged wheels are marked with the word FORGED, cast ones with CAST, but these markings are very rarely stamped on the wheel itself, and besides, when it comes to cheap products from China or Turkey, there is no ruling out the word FORGED being stamped on the surface of a cast wheel.
The next sign you can use to tell a forged wheel from a cast one indirectly is shape and weight. Forged wheels always go through special machining and turning, so, as a rule, they have more even (machined) shapes. It has to be said, though, that in recent years this difference has become less and less noticeable. On top of that, a good forged wheel is substantially lighter (by 20-30%) than its cast equivalent. This last characteristic (weight) only applies to genuinely expensive, high-quality wheels, because the weight of cast and forged wheels made in Russia, for example, is practically the same.
And finally, the last sign you can use to indirectly judge the chances that a wheel on offer is forged: the price. Good-quality forged wheels are much more expensive than cast ones, when it comes to wheels made abroad.