Air on the Side of NOT

I was asked this question by a friend the other day and realized I have never weighed in on this pretty basic, yet important tire maintenance question. If you don't ride for a few days/weeks should you keep airing up your tubeless tires, or just let them go flat? 

Thinking about it, the answer seemed pretty obvious. Let them go flat, or fla-ish. Tires like the Conti GP5KTL, especially the first 300-500 miles, can let go of the rim if air pressure falls below 10psi, but as they age that number drops to almost zero. If you don't let the bike stand on the tires bc it/s turned upside down, or hung, that number is also probably a lot closer to zero based on turning mine upside down a few times.The greater the pressure differential, the faster the air leaks out, so the last 10psi takes 20X as long to leak out as the first 10psi. (this is true for heat too btw, where pressure is called the "heat gradient")

 

 

WHY is this an important issue? Because every time you add air it sucks up some of the liquid in the sealant, and takes it out of the tire as it escapes. Eventually you end up with dried sealant in the tire that does nothing useful. The conclusion is obvious, cycle as little air through the tire as possible so you don't dry out the sealant. This is NOT a recommendation to ride at a lower tire pressure, although I'd recommend a personal search for the lowest number, because it gives a more comfortable, puncture resistant ride, but that's not what I'm aiming at here. 

Also, for those of you who are new to the sport, CO2 molecules are much smaller than air, which is a mix of gasses, and mostly nitrogen, and therefore, CO2 will leak away tire pressure much faster than air. (there's also a special gas mixture you can buy, StayFill, originally developed for fire-extinguisher systems, that will probably go for years without losing pressure if you could somehow manage not to run over thorns, nails, tacks, or glass)

It was 1yr ago on the 25th, Memorial Day 2020 that we found an abandoned dog, which we named Emma, and she's been an absolutely wonderful addition to our, and now my, household. I can't believe someone threw her away, but they did, and lucky us, we found a very scared and traumatized puppy who has grown in so many ways and become an awesome companion. What someone else didn't want, or couldn't keep, was our immense gain. 

To a lessor degree, this is true of old bikes as well. If it's just sitting around gathering dust, find a good home for it and make someone very happy. Nieces, nephews, cousins, and grand-children are obvious choices. My first bike probably cost my dad $25 - back when a buck was worth a buck, but still a bargain.