I’ve seen so many people with milk crates bound to pannier racks. But I can’t do it.
How can I secure the crate to the carrier? I’ve used a few bungee cords but it’s still pretty darned wobbly. The crate is a small grid at the bottom so I can’t poke much through …
Howzabout using some of what I call “tie wraps” – those little plastic strips with the slot on one end, slide the other end through and pull it tight, snip off the end. I think they’re also called “cable ties” or something like that. They come in all sizes.
If you don’t want wobble you need a rigid mount. I’d think along the lines of stiff metal straps placed inside the crate and under the rack, bolted together to clamp the crate securely to the rack. You’ll need at least two pairs (a pair consisting of top, inside the crate, and bottom, under the rack, straps), one pair towards the front of the crate/rack, and one towards the rear. If you’re lucky, you may find some sort of strap at a hardware store with predrilled holes that align with the grid holes in the crate. Otherwise, you’ll need to drill holes in the straps and/or the crate to line them up.
Alternatively, you could bolt the crate directly to the rack, possibly drilling holes in the rack, and using large washers to keep the bolts from slipping through whatever slots or holes are in the rack and/or crate. This would be simpler than the above, but it would provide fairly narrow mounting (less than the width of the rack), and a heavy load could put a lot of stress on the mounts, possibly tearing them out of the crate or rack.
Using cable ties, as suggested above, is easy to do. It could work for light loads if you use a lot of ties, but I question how stable it would be. It’s hard to get the ties really tight without overstressing them.