Thinkin this tire is done,... even if ya can remount it, it's gonna be undependable.
Tires have always been an important matter for me, regardless of vehicle. Most critical, difficult and important issues have been those of my "apartment" (34' motorhome), various equipment, and bicycle tires of the larger sizes.
I'm thinkin you might have suffered a number of accumulative issues here. Up to now, you've had no problems, right? Heck, even cheap tires and rims can be serviceable for a while. But neglect maybe, has kinda caught up with ya, even if only a short term kinda neglect.
Low inflation is likely the major primary factor. Recommended inflation of the tire manufacture IS important, and manufactures max pressure IS within a large margin of safety. Unless a pressure range is specified on the sidewall or in tire specs of manufacture, it's usually best to maintain the max pressure stated on the tire. It's pretty specific to intended use and weight load. But I also wonder of some other "secondary" factors that may have contributed to this kind of failure. Usually kept in the crane??? Few understand the effects of heat and sunlight on tires. Both can contribute to "premature aging", and the light construction of bicycle tires are no more immune than the multi-belted tires of my 34' RV. Add a hard ride over anything that may cause a "bruise",... and you'll have a susceptible weakness that may cause a failure. ANY unusual "feel" to the tires is cause for close inspection and careful watch of a developing issue.
Here's an update, and you nailed it DR! The aluminum box on the crane I keep this thing in, and a brake formed channel mounted on the end wall, so when I roll it in it captures the front wheel, then a motorcycle tie down strap and a hinged metal bar squish down on the rear tire locking every thing in place. I wanted it super quick and easy to get in and out, and it works, less then 30 seconds it's out, another 30 and I'm riding off. BUT.....I think what's been happening, is because I failed to "soften" the edges of the channel, and it has sat in there for a few hundred hours while the crane is working plus going down the road, I think the explanation is simply the channel wore on things enough to precipitate the failure, my bad! I never really ran low pressure in this, as I do my full size fattie I use on rocky trails, this has only been on pavement and a little gravel. The rear tire is the same, and undamaged, no channel back there. A new channel with radius'd edges and maybe some hard foam board of some type should solve the problem.
Perhaps a "bruise" has caused some broken threads in the sidewall area causing an excessive "stretch" in this area of failure, even with low inflation pressure. Cheap tires often have a coarse tpi of cheaper materials that's particularly susceptible to such. Any excessive heat factor can also affect internal bonds and such that keep it all together. Again, cheap tires may not be vulcanized as well as they should or could be,... manufacturing profit issues and minimal specs, ya know. A lot of minor "unseen" issues can contribute to a failure we assume to be from something major. And perhaps it was nothing more than that low inflation pressure. Inspect it carefully, jus to see or maybe feel for anything seen or unseen that might have caused this. AND, check over the other tire assembly as well,.. jus in case, ya know?
With the obvious damage of the bead now, and the possible unseen underlying issues,.... even if tire can be or is remounted, you'll have a matter of concern to keep a careful watch of. May not be a great issue for you if only of occasional use or distance or whatever. But if something you depend on,.... I too, would say it was "toast"! lol
On my 20" folding fat bike I keep in the crane, as a dingy. Too much air pressure? 10.5 lbs was all, and it felt just a bit squishy, can't imagine it was over inflated Cheap tire? Probably. The rim is true, and I have not done any off roading with it. It was fine last time I put it away, about a week earlier. There is another lesser area doing the same thing not shown in the pic. I have no faith in remounting this tire, it's toast I guess?
I need to start treating all 3 of my rides like they could kill me, because they can. The little 20" fattie is especially innocuous, cartoony looking, but it about kicked my ass I'm thinking. Plus, I just rode the eMontague 7 miles across town to a tire shop where I had the crane parked, and when I went to take the front wheel off before folding it I noticed it was loose, and I had been jumping curbs etc. at 20+ mph, not good.
