This was inspired by and created for my beautiful wife Jodie, who is a yoga teacher, and really enjoys riding her bike to the community center and to the yoga studio and area churches where she teaches.
She has an extra thick, extra large yoga mat. I would call it instructor-sized. t took along time for us to find a bag that it fit in. Also, she frequently has to carry CDs, handouts, text books, straps and more in this bag. I've slung it over my shoulder and it's pretty heavy and would cause excessive sweating were I to ride my bike around with it on my back.
Finally, on more than one occasion we realized she couldn't stop at the grocery on her way home to pick up an item or two as she didn't have a good way t carry the parcels.
I resolved to find a bicycle basket that would expand to fit her mat, but retract when not hauling long cargo. Also, I needed it to be reasonably priced. But after extensive searching online and at area bicycle stores, I didn't find anything that satisfied me. Not even close.
So I decided to make my own.
Step 1: Things You Will Need...
Do not use the seat-post only rear rack. Instead, use one with supports that attach near the reear wheel hub. These tend to run between $20 and $40 at bike shops, although when online bike suppliers like Bike Nashbar start clearing out their inventory at the end of each season, you can find then for $10-$15. I paid $12 for Jodie's.
You will also need a sliding under-cabinet wire basket. I used one by elfa that I bought at The Container Store - a two runner easy glider that was 12-7/8" x 16-7/8" x 8-1/2" h.
Finally, you will need a drill with bits for drilling metal, zip ties, wire cutters, two wire-lock pins and four small bungee cords (4").
Step 2: Attach the Basket's Rail Runners to the Bicycle's Rear Rack
To attach the rear runner piece, lay it on top of the rear rack and mark four spots for holes in the cross pieces. These holes should be near a tube or edge of the rear rack. The wheels of the runners need to be facing out. The other end should not intrude on the seat area.
Drill the four holes. (Size them appropriately to your stock and your zip ties).
Zip tie the runner to the rear rack.
Note: I had experimented with other ways to connect the runner to the rack - I wanted easy on, easy off, and as it turned out, the zip ties worked best. You may work out something else. I'd love to know what it is.
Step 3: Modify the Basket - Remove One End.
Be sure to leave the two edge verticals in place, and the crossbar at the top of the basket. The basket form should still feel solid after you remove the square,
Step 4: Roll the Basket Onto the Runner - Open End First.
Next, mark this spot on the outside edge of the runner (both sides) and drill through both the runner's outer edge and the basket runner inside. The hole should be able to easily accommodate the wire-lock pin, which will hold the basket in place while riding in this position.
Once the holes are drilled, slide in the wire-lock pins and give the basket a shake.
Hopefully you just said "that ain't goin' nowheres." Out loud. To nobody.
Step 5: Slide Basket to Extended Position and Drill Wire-lock Pin Holes.
You'll note that the further back you slide the basket, the more it wants to pull down. You are looking for the magic spot - long enough for your envisioned load, yet still balanced with the runners. When you find it, drill through the inner runner rail at the point of the existing hole on the exterior runner rail.
Slide the wire-lock pins in and give it a shake.
"it's a bit shakier, but it ain't goin' nowheres," you should be saying.
Feel free to refer to the extended basket as "X-wing position."
Step 6: Add Some Bungees and You're Good to Go.
If the load feels side-to-side wobbly, we run one on each side from the top of the basket to the wheel hub - it pulls things in and makes them more snug.
The golder rule here is this: Always put the heaviest part of the load over the tire." The milk and canned goods, for example, go over the tire, while the bread and cheetoh's are on the extension. By keeping the load over the wheel, the entire bike feels more balanced, and you handling unchanged by what you are hauling.
My wife has been very pleased with the expanding basket, and rides to her yoga classes almost four times a week. Another instructor at her studio has asked me t make her one as well. When we put my son's trail-a-bike on her bike, we just unclip the pins and slide the basket off.
Like I said, it's not for the heaviest cargo in the world, but for where we are in our lives right now, the expanding basket is perfect. It is a true enabler of bicycle commuting and bike errand running in our home, and (I hate to admit it) I feel really proud of it whenever I see her riding off to yoga.
Good times, friends, Good times.