Originally Posted by
FBinNY
+1, If tires are available en route, either as a carried spare or bought, then when the rear is shot, toss it and replace. I don't bother rotating, and would probably just put the new on in the back, but it's OK to rotate the front tire back if you prefer. OTOH - (IMO) it's not OK to move a rear tire up because of it's wear pattern.
The only problem with putting the old tire in back is the following. The back tire tends to get flats more often than the front.. Therefore, since you're always using an old tire in the rear, you'll continue to get a high number of flats.