Hey Ron, I hear ya! I have only had one set and had a split after one heat cycle, I did have them mounted incorrectly then after correcting, the cracks went away. I find comfort in that I have not heard of any of them going flat. This past weekend Formula 1 had 5 Pirelli tires go flat, if that happened to us, I personally would get off track and insist that we all stop driving instantly even if it meant not racing for the rest of the weekend.
Toyo has replaced every tire that has been sent back which is admirable, but your correct in that that won't matter if we have a wadded up car or maybe worse.
I think the big point on safety at this time is we haven't had any flats as a result of the cracking.
I love the tires, I only did 3 laps on my new set yesterday and went 2 seconds faster than on the RA1's, but one of the negatives is the extra maintenance, being in a rush to change tires to get out for one session on them, I forgot to mount them correctly and the other negative is even if we only get 5-10 more heat cycles out of the RA1's, that does add up over time. Then there is the other factor of finding a new set up and having to keep an extra set of RA1's for rain which eats up a set of wheels that are sitting and waiting for a rainy day, which will have a not so optimum set up for the RA1's.
The negatives are more of a financial and hassle issue, but safety takes this to another level but so far it hasn't been an issue and I would think if they were going to blow, they would have by now.
Glad to see your safety conscience with this crazy hobby that we all share.
See you Friday,