I was able to get some newer QIC-150 tapes by 3M and harvested the belts out of them.  Dropping the belt into boiling water for 20 seconds revived their tension strength. Ultimately what brought me success though was replacing the posts in the tape cartridge with roller bearings that I purchased at a hobby store.  The bearings were meant for wheels on an R/C car. Even with the sticky stuff on the tape, they did not bind up, it required a lot of cleaning of the R/W head though during data restore.