Step 1: Tools and Materials
1 Bicycle (mine is a GT Vantara I got from a Craigslist seller recently)
1 Wire Basket
2 Steel Shelf Supports
Allen wrench (4mm in my case)
Flashlight ('cause I did this at night)
Step 2: Prepare and Dry-fit Uprights
There are two rack-mount points on the frame. They have Allen bolts in them. I don't need those, because I'll be using cable ties at the top. However, I'll be screwing the supports into the lower mount points by the hub, so I'm moving the screws. They were a bit rusty, but I'd had the foresight to add a drop of 3-in-1 oil to each one the night before.
I wasn't sure if the mount points were the same thread, so I checked it cautiously. Then I attached each support with a washer on the screw. Didn't tighten everything up, because I needed to check for fit.
Step 3: Rethink, Then Assemble Basket
These supports have plastic clips that attach directly to the wire of the basket, but I'll use cable ties to reinforce them.
Step 4: Secure to Frame
Once I had everything where I wanted it, I secured it to the frame with the cable ties. The ones I used were 8", so I had to double them. On the top, I put one around the seatpost and attached two more to it, pulling in from the sides.
On the bottom of the basket, I secured it to the crosspiece where the rack mount points are. On each side I used two cable ties connected chain-fashion. To get the cable ties really tight, I pulled on the end with the needle-nose pliers while pushing on the clicky part (what the heck do you call that thing, anyway?) with the slip-joints.
Finally, I snugged up the screws on the bottom. Because they were originally in the long mount points above, the screws are longer than they need to be. It was important to make sure the one on the gear side didn't interfere with the gears or chain. If it had, I would have needed to add more washers, cut down the screw, or *gasp* buy a shorter one!
Step 5: Test
I expect it will hold fairly well, especially if I'm careful distributing the load. I'm planning to keep cable ties in my ride bag for replacements. When I'm flush with cash, I may spring for some perforated metal strip to make the upper mounts more secure. I also want to move the rear reflector, which is currently under the basket. Suboptimal.
If anyone has other suggestions, please let me know. This was a fun build that took me less than an hour. If you have similar parts and a similar need, give it a try!