I’ve never ridden a bike in a skirt. Since I wear tefillin daily, that would be a problematic outcome.
When I was younger, I remember girls would go horseback riding by wearing denim jeans (which prevent the horsehairs from needling you) beneath a skirt (which flowed over the saddle and side of the horse; hence, the pants were visible only at the bottom edges).
Would such an eitza work for a bicycle, or does anything but a short skirt get caught in a chain?