There are two wear issues. The failure of my tire was due to my backpack buckle dragging against the sidewalll of the tire.

I feel so STUPID, because I read a post on this forum about women riding when they thought something was wrong with their bike and how embarassed they were later, and I even thought about this post at the time, but dismissed it, thinking, "I know EXACTLY what's happening, and how could a plastic buckle damage my tire. Well I found out!!

The other issue is the excessive chain wear on the bike. I don't want to transfer wheels, (unlees of course the other chain is just as badly worn. I will check that first.

This is my rear wheel. In general, is it okay to switch rear wheels between bikes? (Assuming they are the same width of course.)

I read Sheldon Brown's article on tire sizes, and it made my head ache!

Mary