The number is not stamped on the barrel. Most do not need this number as long as they fit right. He has his reasons not to make public actual offsets. Here is what he has on the site concerning the offset.
The offsets are confidential. The reason being that there is a ton of work and monetary investment involved in getting them perfected down to the mm. Competitors often pose as customers just to reap said info for their own advantage. This policy is in place for those many eventualities which occur constantly. Other brands often employ this policy for the same reason.
The research involves crawling all data points known, weeding out false data points (almost all listings online have deceptive offsets listed), and then plugging them into an algorithm I made to sort out various tire sizes, lowering, tire stretch, caliper fitments, among other factors. Then there is trial and error. Long before launching the brand, everything needed to be 100% perfected. So real-world tweaking was the next step. That includes plenty of true forged wheels going out and even experimenting with various tire sizes and so on. Even at these prices, that's not cheap. Once that's refined, we then go back into CAD and chop up the wheels to address the various findings. Even our 21x12.5 rears are perfect with no rub. Now multiply this by all the numerous different size options we offer as standard in the C8 Easy-Buy section. Of course, in order to get the maximum safe flushness with the fenders there are mere millimeters to spare. So this is all delicate. Also, we had a goal of having the most flush (and safe) offsets in the industry. And I am very sure we are one of the industry leaders on that objective.
