So, I’d been noticing the past few days that my bicycle tires were a bit low. So this morning, before setting off for work (i.e., inside my apartment), I pumped them up, to the recommended pressure of the tires.
At work, the bike was parked outside, in cool-but-above-freezing temperatures. At the end of the day, I found that the front tire was flat. An annoyance, to be sure, but I took the bus home, and figured I’d figure out what happened and fix it sometime tonight.
Well, it’s now sitting in my kitchen, about 10 feet away from me, and five minutes ago (over two hours after I got home) I heard a sudden loud hissing sound. Sure enough: The rear tire just went flat, too. This is now doubly annoying: Not only do I only have one spare tube at the moment, but I don’t know what caused the flats, and so don’t know how to prevent them from happening again.
Something sharp stuck in a tire would be my guess. It puts a small hole in the tube and because it stays in the tire it acts to block the hole a little meaning it goes down quite slowly. At some point the object may move slightly causing the tire to deflate more quickly. When you change the tubes, inspect the inside of the tires closely for anything sharp. If it is still there your tires will just go flat again. A tip, if you don’t already do it, is to put the tires on the wheels with the sidewall writing (brand name or whatever) over the valve. That way when you identify where on the tube the puncture is, you know where on the tire to find the cause.
That was my default assumption for the front tire, but both at once, and in puncture-resistant tires to boot? And what would cause it to move slightly to cause the sudden deflation, when it was indoors and untouched? I haven’t inspected the tires thoroughly yet, but I have marked the position on the tires that lines up with the valve.
And it looks like I’m riding the bus again tomorrow, in any event: Not only do I only have one spare, but I just discovered that my patch kit isn’t any good, either. The little tube of glue appeared to be half-full, but it turns out it only contained gas, no liquid.
…And, it appears to have been a (bizarre) coincidence. The front flat was caused by a whisker-thin bit of some sort of wire, which I think must have been inside the tire all along, because there’s no way that something that thin could have been rigid enough to be driven through the tire from the outside. The rear tube, meanwhile, had a very large rip on the inside surface, that looks consistent with the rubber having just plain worn out. I can’t find any evidence of a spoke poking through there, or the like.
Though I suppose that it’s not a total coincidence: Both problems were presumably already there in latent form, waiting, and triggered by the tires being fully inflated. And of course, the only time I’d ever have noticed the glue drying up would be when I was attempting to patch a tube.
Check the rim strip very carefully on the rear tire. I’ve seen cases when the pressure of the tube moves the tape just enough for the edge of the spoke hole in the rim to contact the tube then cut it. One the pressure is gone, the tape moves back in place. If it happens again, I’d recommend new rim tape.
As far as the tire pressure if there is only one value (like 120 psi), that’s the maximum pressure for the tire. You usually don’t want the maximum pressure. My road tires are rated at 120 psi but I ride them at 100 psi and I weigh around 215 lbs. Some tires have a range like 65-85 psi. In that case I usually use the middle of that range for starters.
The reason that I bring up the max pressure thing is with the temperature changes, it might have been a factor. If you filled up the tires in the cold then brought the bike into a warm building, that could raise the pressure and unseat the tire from the rim. Of course you said that you inflated them inside your apartment, so that probably wasn’t the issue as taking the warm tires out into the cold could reduce the pressure a few psi.
That’s the problem with patch kits - once you open the tube of glue, it will dry out in a few months even if the cap is on tight. But you can buy just the tubes of glue, in bulk. I know that’s not going to help you today, but something to consider in the future.
Personally I always try to stock 3 spare tubes.
I’ve never seen a tube fail just from age. I would look very carefully at the rim tape. Maybe the pressure causes the tape to shift to the side?
Most likely the thin metal sliver is from car/truck tires with steel belted radials wearing out and depositing the fragments along road shoulders. Dragging your finger around the inside of the tire might find more - ouch. A bike rally many years ago in Flagstaff, AZ had some routes that used the interstate (legal for some sections). Flats came in bunches along with torn finger tips. Locals used heavier tires with Kevlar belts along with a protection strip between tire and tube (can’t remember what they were call?).
Those strips used to go under the name “Mr. Tuffy”, not sure what they are called now, but they are still around. In addition to what the others here said, if the roads were damp on your ride, you can be prone to more flats, as your tires may pick up more debris that would otherwise not stick in dry conditions. I would add that fixing a flat is an opportunity to inspect the inside of the tire, rim, rim tape, valve hole, spokes, hub, etc. for anything needing attention.
Instead of a bare finger, drag a cotton ball around inside the tire. Any snags will be real obvious. But less bloody. A crumpled tissue works not quite as well but everybody has TP & Kleenex at home.
this has happened to me too. Two tires going flat right at the same time, and even their Replacements went flat. That’s 4 inner tubes in one day. Just like you I was completely baffled, but there turned out to be a reasonable explanation and it was not a mystery.
Just an update, I’m going to pick up replacement parts (and spares and spares for the spares) today, and probably get everything put back together tomorrow. I’m not sure if the rim tape was the problem, but I’m going to replace that, too, just to be sure.
And I’m a bit puzzled by the glue tube. I wouldn’t have been too surprised if the contents had solidified, but the only way I can see it becoming full of gas is if most of the mass of the stuff is in a volatile solvent which leaked out, and even there, I’d expect the tube to end up completely full of gas, not just half-full.
I’ve been biking for decades. I learned early on that the key to reliable biking is to carry tubes and tools and to diagnose a flat the first time. Remove the wheel from the bike. When the tube is pulled, make sure you “index” it so you know the relative position of the tube within the tire. Blow the tube up and find the leak. Then go back to that position in the tire and find the hole. Sometimes you will still find something stuck in the tire. Running your hand around inside can produce a nasty cut. If you don’t make sure there is nothing inside, you risk a second flat while on the road. I’ve made that mistake as well so I carry two tubes and a patch kit. I could be miles from home and can’t take any chances.
I’ve gotten several flats from the remnants of steel belted radial tires, as well as glass, and pinch flats from hitting rocks. The rip in the tube could be a result of having it pinched between the rim and tire, i.e. it wasn’t properly seated. Another thing to watch out for is the valve stem. I’ve had many tubes wear through at the valve stem where it touches the rim. A few strips of electrical tape on the inside of the rim, over the rim tape, then poking the valve stem through fixes that.
Agree. I had this problem with a rim - my McGyver solution is to take an old tube, cut-out the valve stem around the thicker rubber, then cut-out the valve itself. You are left with rubber “donut” - just place over the new tube valve stem and it protects against this sort of problem.
Bringing the bike inside. Where it’s warmer, may have exasperated a previous problem.
At Iron man races, the athletes air up their tires early in the morning, leave the bike to go swimming and then retrieve their bikes for the next leg.
Often these bikes are in an asphalt parking lot, it gets hot by the time they come out of the water.
I’ve volunteered at these races, and you can often hear bike tires burst from the extra heat as the day warms up. Sounds like a gun going off, can’t miss it. Happened to my wife once.
Well, I always bring my bike inside when I’m at home, since my previous bike basically fell apart from exposure to the weather. And the first flat, the front one, happened while it was outside, but not during the 30 minutes that it was actually being ridden.
One thing I forgot to mention before, I switched to Continental Gatorskin tires and haven’t had any problems with flats since. Rocks, glass, metal shards, they’re just shrugged off.
Yeah I haven’t had a puncture all year since I switched to super tough hard case tires.
Yeah, you might lose a little performance but personally I’ve never noticed any real difference and the peace of mind of being able to cycle 10 miles to a friends and not having to worry about getting a puncture when you’re coming back is totally worth it.
