I noticed some cracking on my rear tire several weeks ago, but it appears that it is getting worse.
So through my vast automotive network, I managed to find the contact info for the engineer in charge of land speed tires at Goodyear and sent these pictures. Apparently they haven't made this tire for a while and so i just got one that was already really old. He said it is structurally fine to use, but offered to send me a new one for free anyways. Three days later, bam! Free tire.
No cracking on this one, and he told me to just keep it wrapped up when i'm not using it and it will last a while.
Goodyear is my new favorite tire company.