As is the fashion of the current day I ride tubeless on my gravel set-up. This past weekend I picked up two shards of glass early in the ride, after a bit of latex spray both holes sealed and I was on my way. There while waiting for the ferry there was some discussion with my fellow riders as to whether I should dig out the glass and repair the tire with a plug or just let it ride; I let it ride. Thirty miles later I picked up a staple that induced a slow leak. When we stopped for some food, I decided that it was time for a tube. I figured that a tube was the fastest and easiest solution to my slow leak problem; it should get me home where I could then either repair or replace the tire.
After being unable to find any offending debris in the tire I installed the tube and went on my way. Early on I could tell that I had a slow leak, but I was able to get about twenty miles down the road before it became unrideable. A second inspection of the tire – nothing – and a second tube nearly got me home.
My thinking is that over the life of that tire I’ve picked up a number of objects that normally would have punctured a tube, but since it’s tubeless debris simply remained embedded in the tire. A small thorn or a thin piece of wire (such as strands from braided cable that seem to litter active and former logging sits) are virtually impossible to detect with cold, latex soaked hands. It seems that putting a tube into a well-used tubeless tire has a significant chance of either an outright puncture or developing a slow leak as a minute object migrates into the tube (an outright puncture would actually be preferable as you could then find the hole in the tube and then trace it back to a location on the tire).
In hindsight it seems that plugging a hole in a tubeless tire is better than putting in a tube, because once you put in that tube you could fall prey to any one of the small undetectable pieces of debris that may be silently embedded in the tire. Perhaps a second solution would be to bring along a second tire, and instead of adding a tube to an old tire you simply put on new rubber.
This type of issue doesn’t really come into play on “normal” road riding during which you can call, family, a friend or an Uber for a pick-up, but when you’re on some abandoned road twenty miles from a pick-up spot you start to think a bit more about “how am I going to get home.”