Thanks, all! This was a 1998 I bought inTucson. He said he put new tires on the front but they were 12 years old. Caveat emptor.
And the one that failed was in the rear. So we're getting 4 new tires all around.
It was just a very scary thing. But we should be on the road by noon tomorrow. Woo hoo!
This is such a great group. I've learned a lot from all the wonderful posts here. Many thanks to you all.
Happy trails,
Robin