Sure, you need a pannier. But can you pack an entire beach picnic into those other puny panniers? Well can you?? Go. You go try. I'll wait here.
Not even close, right?
You need a BIGGER pannier.
You need the CADILLAC of panniers!
I started this project with one goal in mind: I want a single, easy-to-attach pannier big enough to haul two fully-loaded grocery bags home from the store. My other panniers & racks were too small, or too poorly balanced, and I was sick of bags dangling dangerously from my handlebars.
I ended this project with The CADILLAC of Panniers. It is a giant-yet-maneuverable, eye-catching, hard-shell pannier made from a vintage suitcase. Just like taking a spin in dad's wood-paneled station wagon, whenever I take my pannier out I get stares registering on the spectrum between pure awe and comic disbelief. No joke, people have stopped me for photos. The economics of used baggage are such that a hardshell suitcase like this sets you back only $5 at the thrift store. Add $10 for nuts, bolts, hooks & chain, and you've got a boss pannier for $15.
Step 1: Mounting Brace & Reinforcement
For specific build instructions, there are plenty of other great recipes on Instructibles. In particular, Bike Pannier from Old Briefcase has good general instructions for converting a bag to a pannier, and Alternative Homemade Pannier Bungees inspired the upside-down tie-down hooks I used in my design.
Below are some design consideration to look out for as you fashion your own Cadillac.
- I reinforced the mounting braces on both the front & back surface to distribute the load away from the hook holes. I used strong adhesive glue between the wood brace & the plastic case.
- Make sure the mounting braces are level. The contour of the case makes it hard to eyeball it. I used a level to draw a level line to guide my hole drilling & placement of the braces.
- Plan for exactly where the hooks will rest on the bike's rack before you start drilling holes for the hooks. There will be some places that the hooks WON'T work.
- You probably can't mount the pannier hooks in the middle of the case, because doing so would obstruct your foot when you pedal. Make sure you give your foot enough clearance when the bike pedal is closest to the bag.
- If you're going to use the tie-down hooks as mounting hardware, the deeper hook the better. If I were to do it again, I wouldn't use the 1" tie-down hooks shown here, which are too shallow for comfort. If I hit a bump hard, the front hook can jump up off the rack. I always have to strap it down tightly.
- If I were going to build it again, I'd go for a less-wide suitcase. There's a lot of space behind that back hook, and when I load my groceries with too much weight in the back, the front hook can see-saw off the rack. I always use a bungee cord to hold the front hook down tight.
Step 2: Chains to Restrain the Opening
- Depending on what material the suitcase is made of, you might need to drill through metal to attach the chains.
- The level of the chain matters. If you place the chains just right, the chains act as a side barrier to keep stuff from falling out. If you place the chains too high or too low, there might be a gap big enough for smaller items to fall through.
- Make sure you measure the opening right at point that you plan to attach the chains. Too little chain length, and you won't be able to fit cargo through the opening; too much chain and the case might hang too far open. A good guiding question is "Can I fit between two parked cars with the suitcase in open position?"
Step 3: Miscellaneous Considerations & Safety
- Drill air holes in the bottom for ventilation in case you spill water inside. I learned the hard way after a fun, wet trip to the beach. If you get the bag wet and store it closed, it will grow mildew. You can drill air holes that allow the bag to ventilate between uses.
- Riding with The Cadillac isn't a problem for a sure-footed rider, but adding 30 pounds of groceries to one side of your bike will change the balance of the ride. I don't really notice the difference anymore when I ride with a heavy load of groceries, and I'm not really moving that fast when I ride home from the store anyway. The bigger challenge is actually in loading & mounting the bike gracefully since the weight is so loaded to one side.
- Be sure that your bike rack is strong enough for the amount of weight you're loading up. I consider it a point of success that with The Cadillac I sometimes have to ask, "Is this too much weight for my bike rack?" As always, be safe.