Leaving work Monday, I get downstairs and my tire's flat. I patch the tube and ride home.

Next morning, it's flat again. A different puncture. I replace the tube and leave for the office.

I get a new flat on the ride to work. Patch the tube and keep going.

I get downstairs that evening, and the tire has gone flat again. I take the train home.

What's going on? I'm pretty confident in my tube patching abilities, and every time it's been a new puncture, in a different spot in the tube. I scoured the tire for glass, rocks, anything embedded that could be causing punctures. Nada. The tubes have been fully inflated and seated properly.

Two possibilities stand out in my mind. One is that it's a 32 mm tire and the replacement tube was 25mm. But that doesn't explain the two flats on the old tube, which was a 32 mm tube. Maybe the first two flats were bad luck, and the second two were from using too small a tube? My understanding is that you can usually get away with using small tubes, but maybe I'm wrong.

The second thing I noticed is that the tire is getting pretty worn out. It's not at risk of blowing out any time soon, but there's some cracking in the sidewalls and a couple irregularities on the inside of the tire. Could having a worn tire cause so many flats so frequently?

What do you think, bikeforums? Coincidence? Bad selection of tubes? Time to replace the tire? Is there anything I'm not thinking of?

Quite probably. The irregularities inside would be enough for me to replace. Do you install the tire the exact same way every time? Label over the valve stem? (I am assuming you do since you can tell that the punctures are in different places)

when repairng the flats do you look to be sure something is not still lodged in the tire? are you pinchingthe tube when you put it back together?

Last year I got 11 flats in one month. It was mostly on my road bike both front and back tires, but also on my hybrid. Except for one time it was always hard to see small pieces of glass. The only reasons I can think of was the dry weather was allowing an extra build up of road debris and my tires were worn out. It stopped after changing to Gatorskin Hardshells.

I can't find anything lodged in tire. I check thoroughly every time. Not pinching the tube, either.

Yep, label over the valve stem. It's hard to tell, though, if the bumps and irregularities line up with the punctures. I think not exactly.

I'd bet the tire is worn out. Most tires I've seen have a layer of hard(er) rubber on the outside; when that wears away, it exposes a thin layer of softer rubber. That soft rubber grabs and holds every thorn, rock, or piece of glass until it squirms into the tube and punctures it.

Replace the tire and see if the flats don't stop.

do you looks or run your fingers through it?

is the tire is close to worn out just replace it.

All the above advice is good above do you live in an area with goat heads? if so this is the time of the year for them.

Sounds like the radial tire wire flats. The wire can be hard to find.

Assuming it is the tire, is it normal for tires to go from no flats to a ton of flats? You would think that the number and frequency of flats would increase more slowly. The tire has had one flat in the past three months and then all of sudden four flats in two days?

In my case it happened all at once, no preamble to the flats. It's like the tires just gave up.

I'd chalk it up to just bum luck. Or maybe good luck in the case of only one flat in three months. I've ridden several thousand miles in a year with one or two flats. Last year I had about 20, including two within five miles of each other, and all of them explainable. I don't know if they've cut down on street sweeping around here, or if it was just bum luck.

I am curious, but have you ever tried tire liners? I have had great luck with it. If not, it's probably time to replace the tire.

Good luck.

Replace the tire

I once had a series of flats. I tracked the problem down to an almost invisible sliver of glass beneath the surface of the tire. The sliver did not show from the outside or the inside of the tire and I could not feel it. I found it by flexing the tire sharply under a magnifying inspection light.

Four flats in two days isn't a common occurence. In addition, you seem to have ruled out the most likely causes of frequent flats (pinched tube, glass remaining in the tire, migtated rim strip).

That causes me to wonder what is unusual. You say your tire is old and has cracked sidewalls. If it was my bike, I'd buy a new tire. My bet is that'll fix it.

I once had something caught in the tire of my beater bike that I never did find. After fixing a few flats (all in the same place) I cut the valve stem out of an old inner tube and installed that as a tire liner. It worked but, eventually, I acquired some extra money and replaced the tire. I never did find what was causing the flats, but it was worth the cost of a new tire to eliminate the problem.

You most likely need to replace the tape that goes around the inside of your wheel rim -- or at least check it carefully to make sure your punctures aren't coming from your spoke ends. Been there, done that. rcd

Maybe you are riding over some finely ground glass or other such crap?Car wreck debris or construction debris that some idiot in a pickup just let drop all over the road?
Those goatheads are nasty- if you live in a goat head burr area-they are the WORST FLAT PRODUCERS I have ever encountered-Flagstaff AZ taught me that lesson 10 years ago- 15 punctures in 6 tires in just 400 yards)
Charlie

Schwalbe Marathon Plus tires .. they put the tire liner puncture protection In the tire casing.

Tire liner strips shift inside the tire with every rotation,
inflation needs to be rock hard to reduce it, grinder wheel tapers the edges of the ends,
I do that when we sell, and Install them in the bikeshop.
that also reduces the wearing a hole in the tube from the end of the tire liner problem.

Reduce, extends the time.. not eliminate.

I'm pretty sure that it's the tire being worn. There are a number of spots where the threads are exposed that seem to line up pretty well with the punctures. They're not sharp, but I can envision a situation where the roughness caused by the exposed threads is grabbing onto the tube and causing a flat. I've already ordered a new tire, but just to be sure, I'm going to try covering the exposed threads with patches and seeing if that does the trick.