diy: bike pannier

I've been riding my 1970's Schwinn World Tourist (actually, Allen's mom's old 1970's Schwinn World Tourist) around town a lot lately, much to the chagrin of my friends who have to hug me when we meet (it's still hot in Atlanta). NOT to the chagrin of my wallet, lip gloss, cell phone, and other accessories that want to ride along with me, since I made a handy bag to keep them close to my left foot. It also doubles as a shoulder bag that I can carry around after I get off my bike.

Instructions after the jump.

You'll need:

• a yard or two of heavyweight fabric
• a quarter-yard of bump-cloth (soft, fuzzy, delightful stuff that's used to line curtains - it runs about $12/yard at fabric stores)
• some waterproofing spray (optional, and available at hardware stores)
• a couple of yards of nylon webbing
• metal D-rings to match the width of the webbing
• a flexible plastic board, to lend rigidity to the back of the bag (lightweight plastic cutting mats work great)
• heavy-duty metal snaps
• 2 small carabiners
  
• fabric chalk, or a disappearing-ink pen
  
• a sewing machine

The plan for my pannier was a messenger-shaped bag, sized to fit a MacBook, with two interior sections divided by a padded panel - I could slip the computer into the back section, and the panel would keep my bike lock, wallet, and everything else separate from it. Here's a breakdown of how the construction went. The first piece is the padded panel.



Follow the manufacturer's instructions to waterproof your fabric, then let it dry. You can give the finished product a second coat later, if you like.

Measure your computer to see exactly what size the middle panel should be - I used the computer's exact dimensions.

Cut out the panel accordingly, leaving 1" seam allowances. Then cut out the same size bump-cloth. Straight-stitch the two panels together, following the outline of the dimensions you drew.



To quilt the panel, take a metal ruler (or a piece of board cut to about 16" by 1.5"), and lay it diagonally across the panel, and trace both edges with chalk. Now realign the ruler along one of those lines, and trace the other edge, and so on. Straight-stitch along the lines you've drawn. Lastly, hem the top of your panel.



Now you're going to want to put padded sides onto this panel. Cut a length of fabric about 12" wide, and 1.5" longer than the height of your finished panel. Cut bump-cloth in the same size. Pin the bump-cloth to the back of the fabric, hem the top, so that the bump-cloth is sewn to the fabric. Now cut the fabric into four long strips, with the hem at the top. Straight-stitch down the sides of the strips, leaving 1-1/2" inches in the center, between the two rows of stitching. These four bands will be the sides of your bag.

Straight-stitch one of the bands to each side of your padded panel, with the front sides of each piece facing each other, lining up the stitching on the strip with the edge of the panel's padded area.



You've got this step done:



Now sew your remaining two bands onto the back of the panel: fold in the panels you've just sewed, so that they're laying flat on top of the panel. Lay this over your second strip, and sew right on top of the first strip, about 1/8" away from the seam. This will push down the first strip, and make a little lip.





This step is done now:



Now that you've got all your sides attached, it's time to make the piece that will form the front, back, bottom, top, and flap on your bag - one long, continuous band.

Your fabric will be the same width as your padded panel, plus 1" seam allowances. To see how long it should be, add the height of the panel (this corresponds with the front of your bag), plus the width of your sides (corresponding to the bottom of the bag), plus the height of the panel again (the back), plus the width again (the top), plus about three-quarters of the height again, depending on how long you want your front panel to be - plus seam allowances. In short:

(height*2.75) + (width*2) + 2" = the fabric's length

Now you'll want to figure out where the back of the back will be, because you need to pad this and reinforce it. Cut out another piece of fabric, corresponding with the size of your padded panel, and a piece of bump-cloth of the same size, plus add to its height the width of the bottom. Straight-stitch this on to the back of the fabric so that it corresponds with the back and bottom of the back. Straight-stitch across where the back becomes the bottom, too. Then trim the bump-cloth to about 3/16" away from the stitching.



To reinforce the back of the bag, you're going to basically sew a big pocket onto the back of the bag, slide the plastic in, and stitch it closed. Cut your plastic slightly smaller than the size of your padded panel - I scored and glued two chopping mats together to make it stiffer. Then straight-stitch a pocket, with closed hems, on the back of the bag, leaving the pocket open at the top of the bag. Don't put your plastic in yet.



Finish the edges that will show: hem the edge of the fabric that corresponds to the bag's front-top edge, and hem all of the edges of the bag's front flap. For both of these, you could also add another layer of fabric, if you'd like, hemming the edge with the front-sides facing each other, then turning it right-side out so that the seams are hidden.

Cut a length of nylon webbing so that it equals the width of your bag, plus three times the height. Center the webbing on the outside bottom of your bag (the place on your panel that you've already reinforced on the inside), and sew it to the bottom, stopping short of the seam allowances.



Now line up the back of your bag (the padded and pocketed part of your fabric) with one of the back-side bands on your bag. Sew the edges together, with the front sides of the fabric against each other, so that the seam is invisible when you turn it right-side out. Repeat with the other back-side strip, and the two front-side strips. You're almost done!



Slide the plastic into its pocket, and stitch the pocket closed.

Now, run the loose webbing up the sides of your bag, slide on the D-rings, and double over the webbing. Straight-stitch the webbing up the sides. It's hard to get to the webbing all the way at the bottom of the bag, so I just stitched the top half, where my sewing machine could reach.



Some parts of this bag are "floating" - you can stick your finger between the sides and the bottom of the bag, for instance. If you like, stitch this closed by hand. Also, the middle panel floats, which sometimes allows, say, your cell phone to migrate from the side you thought you put it in to the bottom of the other side. If this drives you crazy, stitch it closed by hand.

Lastly, put in heavy-duty metal snaps for closing your bag.

The bag attaches to a back rack with small carabiners, available at hardware stores (or free, emblazoned with the name of your college's recreation center - everyone has a drawer full of these, right?). Someday, I'll get around to making a removable strap to attach to the D-rings. For now, I'm just using some nylon grosgrain that I tuck into the bag when I fasten it to my bike.