…on the ebike.
This happened once before, in 2019 shortly after I got the bike. No explanation: I came into Ian’s to get it and the front tire was utterly flat. At the time I assumed I’d run over something and went ahead and swapped out the tube, but there was nothing in the tire and the tube held pressure for months.
This time, exactly the same thing. I parked the bike with no problem, came back a few days later to a completely flat front tire. This time I just aired it back up and rather timidly…
…rode it to town and back. A trip which was completed with no problem whatsoever. It’s kind of mystifying: I’m pretty sure nobody’s sneaking into Ian’s Cave and matchsticking my bike tire.
Friend of mine had one where if one spot on the tire was on the bottom when parked the valve would leak. Something to do with the pressure it applied.
I was seeing same issue, found very small thorn bits stuck in tire that seemed to work their way in and out to poke into tube at certain times. I only found them by feel couldnt actually see them on inside of tire I went around and pryed them out with a knife and small tweezers. I do visual checks on the tire after each ride now. I added the Mr Tuffy liners to mine since there are no thorn proof tube for fat tires for some unknown reason!!. Since then no issues. Go with the size larger liner than recommended, it will cover sidewalls better.
Since the tires are tubed I’m going to rule out the rim. (I’m just that smart] I did have problems with a tubed tire, spoke to a mechanic friend and he suggested tightening the valve and replacing if that didn’t work. Sure enough I removed the valve cleaned around the threads with a q-tip and screwed it back in tight, the problem went away.
Open the schrader valve cap, unscrew the valve center with an appropriate split cap or tool, inspect the rubber seal and the rubber coating on the spring loaded center. Clean it all with water and a lint free rag, dry well, re-assemble. Over the years I have had slow leaks from minuscule bits of dust or sand particles that get in there and with all the bounding a bouncing, can cause a slow leak.
If nothing else, KNOWING you valve is clean and working correctly lets you find what other cause might be if it still leaks. Tighten the thing finger tight, do not torque it beyond what you can do with two fingers.
I use those petroleum-product black sandals you see at Walmart. They last about 6-12 months before I start getting intermittently poked in the soles of my feet.
Texas and my cactus hobby means I have a lot of spines around. They break off in the sole and can work their way through to my feet.
I can extend their life by using a 5-pound sledge to ‘massage’ the sandal, breaking up the embedded spines so they don’t poke me.
While this isn’t your problem, I could see it being a vaguely similar action, i.e. pokey objects migrating in and out of your petroleum product tires.
I have an alternate theory about parallel universes, but I’ll save that for later.
That would be why we carry a small pump, spare tubes, and appropriate tools in a small bag. I’m too old to walk the miles back home when cycling in the outback.
When I lived in California, I discovered that my bike tires were a magnet for goatshead thorns (AKA puncturevine). The worst was when I got into a patch of the seeds at night; flatted both tires, and the thorns worked through the tube liners.
As memory serves, I was able to dethorn the liners, but both tires and the tubes were a total loss.
Agreed with above; check the valve insert for grit and/or being loose.
I would change the valve and see if it still happens. Had a similar experience with my mountain bike and that solved it.
The best way to ensure that your Schrader valves can’t leak is simply to keep good tight valve caps on them.
On that bike, with those huge tires, sub-10# air pressure might seem to ride perfectly okay, but at very low pressures a valve may not seal reliably. So if you let the pressure drift too low, the tire could possibly go flat (say) overnight. The cure? Checking air pressure regularly and keeping valve caps on.
I’ve never had 4” wide tires, and so don’t know if this will work for you, but on my bikes I have gradually developed a “calibrated hand”. With a quick squeeze, I can estimate tire pressure +/- about 10#. I do it before every ride.
I wonder if Armadillo makes their puncture resistant tires in whatever size your e-bike uses.