I sent Simple tire an email and got this back from them. "Sailun does not advertise it as an all-steel, and they only list the recommended rim width. The tire weighs 56 pounds each."
So I have an email off to Gosailun for more info.
Spending the money for 17.5 rims and then installing a tire with little history seems a little strange. Might be better to spend the 100 each more for Sumitomo ST727 215/75R17.5 tires. They have an approve rim width of 6-6.75" same as the Michelin XZE2. For some reason the XZA Michelin area of their web site is down right now.
Chris