They're aluminum unfortunately. Looks like some stress cracks. Not sure if it's holding air yet, all of my tires were about 1 pound low from airing up this afternoon (possibly 3 pounds but I can't remember if I put 34 or 36 in but 3 pounds low on all four seems crazy). 1 pound could just be from change in altitude and air temp. I topped all four off about 45 mins ago and will check them again in a bit. Another tire has a bad valve stem, if you push it to the side air comes out, so that one might be loosing air as well.
I had initially planned on that, but then got these for a good deal and decided they would be good to have in the north east. Rethinking that...
It doesn't look too bad. If a big chunk of the lip broke off I would be worried.