Years ago I was out for a solo ride and suddenly felt that tell tale squishiness from my rear tire. Dang, a flat! No problem. I had the spare tube that I had been dutifully carrying around on that bike plus a frame pump. Well, that old spare evidently had developed a crack at the valve. And I didn’t have a patch kit. Thus ensued about an 8-mile walk home. On the way I started eyeing crappy bikes locked up at bike racks to “borrow” a tube, but just couldn’t go there. Now I carry a spare tube plus a patch kit.