Carry a strong cane, and stick it in the front spokes.
Or a sawed off broomstick or mop handle.
Get an electrician to bend you a cane from electrical conduit. Fill the top handle, and the bottom 1 foot with lead shot and epoxy glue. Paint it brown or black. Tape the handle, and get a crutch tip from the pharmacy. Quite formidable for swinging and poking/jabbing.