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.