Sandal bags. A bag to carry a pair of Teva sandals on my bikes, esp Jessica J, my good fixie.
A little background re: the need. I've been having multiple foot issues since getting this bike and deciding to ride the vertically challenging Crater Lake Cycle Oregon two years ago. My feet (esp my right) had issues witht he doubletoestraps I usedmost of the year and for CO. Also I can rarely get three straps shoes to be tight enough to keep my toenails from being jammed (I climb very toes down) while not causing issues with the bones of my upper foot. (And riding fixed, loosening straps for the flats and tightening for the climbs is not an option unless I am willing to come to at least a near stop). I can't wait for that new 7 point custom tightening system to hit shoes I can buy.
One thing I have started doing that helps a lot is when not riding, wearing sandals. I was never a fan of sandals, but my pinky toe sure is. These days, it gets more say than I do, since it always has the option of sulking, getting infected and sending me to the doc for another 10 days of anti-Bs and GI issues.
So, how to feasibly carry sandals on a dedicated fixie? Under the saddle/toolbag would be the logical choice but I have a sweet system for carrying my spanner/wrench there; something I use for every roadside wheel flip to change gears. In the main diamond? I could but it blocks access to the WBs and I rarely drink enough riding fixed anyway. Under the DT? Sounds perfect, but how?
Well, I found a WB cage that looks made for the job. Heavy aluminum with the cage forming sides instead of a top. So the sandals can simply be slid inside, with the soles in plane with the bike diamond. But this is a fix gear. Those sandals and straps better be really secure! Anything in the path of fast moving fixie cranks is a real problem. Something will break. So I designed a zippered bag that would fit the sandals snugly. A toestrap secures the bag inside the WB cage, both keeping it from falling out and insuring it will not interfere with the front wheel/fender. (It is quite close.) I had a local outdoor fabric company fabricate a prototype bag to my pattern and used it a couple of weeks. It is too tight and the final zip is tough so I redesigned the patter and had a 2nd made. Sweet! In a few minutes it goes for it's first ride. And I an realizing the 1st wasn't a waste. Saturday mornings I carry my sandals in my panniers as I go to the farmer's market. Now I have a clean bag that takes very little space to carry my sandals beside food. (The 2nd bag will live a life of filth as it is in direct line of all front tire debris/water. But the sandals stay clean.)
This didn't end up being cheap. But then, neither are those doctor's visits. Of course, I could just stop riding fixed or just stop riding.