Just to clarify, I'm hoping someone else has these and can confirm. Because it appears to be 21mm. Every auto parts store hasn't had anything this big, even on special order. As well as HF and Discount Tire. If someone is recommending other tire places - you'll have to be more specific.
The closest I find on the internet is here from Summit Racing, but these look like they are on their original rims.
https://www.summitracing.com/parts/rpm-c7301/overview/
These are also very deep, while all the others that I have found are shallow.