I have a pair of Trek panniers that I use for commuting and on bicycle tours. They aren't particularly high-end, but I like them and use them frequently. As with most panniers, they attach to a rear or front rack on a bike using two hooks at the top and an elastic band at the bottom. When removing the bags in a hurry one day, I yanked a bit too hard, and the elastic band came away from its attachment point.
The bag still works, but if I hit a big bump it will fall off. Not a good thing when commuting on busy city streets! This instructable shows how to reattach the band.
1/2" Heat shrink tubing (I used a section about 1 1/2" inches long)
Key ring (about 1" diameter)
Exacto knife or box cutter
Optional: Short (~6") length of string and duct tape.
Step 1: Remove Heat-shrink Tubing
The attachment point is covered with a section of heat-shrink tubing. We'll add a piece back at the end, but for now we need to remove the old one. It came off really easily for me with an exacto knife. With that gone, we're left with the bare piece of crimped metal. It's crazy that's all that was holding the elastic band in place!
Step 2: Open Up Crimp
To reattach the elastic cord, we need to open back up the crimped metal. This was a little tricky, but the best way I found to do it was with two screwdrivers as pictured. I stuck one in each end and torqued them in opposite directions. With a little elbow grease, the crimp opened up enough to admit the elastic cord.
Step 3: Reattach Cord
This might not be necessary, but to make re-threading the cord easier, I attached a piece of string to help pull it through the crimp.
Before reattaching the cord, make sure to slip a piece of heat-shrink tubing over it. Also, with my panniers, there is a metal ring threaded onto the cord which clips onto the rack when mounting. I lost the ring when my bag broke, so I substituted a key ring.
Using the extension, pull the cord through the crimp. I chose to tie a knot for extra security. Using a pair of pliers, re-crimp the metal piece so it pinches down on the cord.
Step 4: Heat-Shrink!
Slide the heat-shrink tubing over the metal piece and then use a heat gun! I used the lowest setting, so I didn't melt the pannier fabric.