Cause of death: snake bite. Or was it?

 A regular customer brought his bike in to be checked after he’d had a flat tire out on the road. He’d put in his spare tube and pumped it up to full pressure at a nearby friend’s house before he made his way home, but wanted a professional eye to make sure that he hadn’t missed anything.

By his account, he’d done all the right things. But the holes in his punctured inner tube were a classic snake bite, when he is conscientious about proper tire pressure, and did not recall hitting anything like a stone or a pothole.

It was the rear tire, as usual. I pulled the wheel out and examined it carefully. He had not perfectly noted which way the tube was oriented, so I had to look in both directions from the valve stem. There was a faint scratch on one end of the arc and an almost imaginary ding at the other end, corroborating a snake bite either way.

No debris showed on the outside of the tire. The twin holes that we’d all seen would have needed a thin but long object, like a finishing nail, to have gone and and fallen out again before he stopped. Yep. This had to be the snake bite that it appeared to be.

A responsible mechanic always checks the casing, regardless of the cause of the flat. It takes maybe an extra minute. I was perfunctorily sweeping my fingers through the tire when I felt like telltale poke of sharp debris. Wire? Thorn? I had to pull it down through the casing because absolutely nothing stood up above the tread. It was pointy, dark, and ferrous. Not the usual skinny wire fragment, but possibly thicker wire in its youth.

Because the rider had traveled 13 miles home after fixing the flat, he could have picked up this little ninja on that part of his ride, and just been lucky that he didn’t flat again.

Feeling like a crime scene investigator, I clamped the snake bite holes in his old tube and pumped it up. After a careful search, feeling for the faintest breath of escaping air, I found the tiny pinhole of the initial puncture that started his misadventure. It was like one of those crime shows where the cops find a victim with obvious wounds and build a scenario based only on those and then the smarty pants detective finds the other thing that reveals the true perpetrator.

My theory is that the rider hit the poky debris without realizing it. Air very gradually escaped until pressure was low enough to get the obvious and faster-acting snake bite from a surface hazard that might not have imperiled a fully inflated tire.

It’s only trivial bullshit, but it provided a bit more entertainment than your average flat tire.