I would not recommend these tires if you have back pain. I also swapped out my standard Airs for my 36" Snapper Pro s50xt deck. I would classify this material as a hard plastic as opposed to the OEM seals on my scag mower which are more heavily rubberized. There was an instant difference in feel as soon as I put them on and I wish I had never bought them, but I've grown fond of them now and it's less noticeable. A tire I received was completely rotten but I haven't sent it back yet so they billed me for it.