I see a lot of people post here who are shocked that other people have so many problems with flat tires. They often seem to assume that those who suffer from frequent flats either bought the wrong tires or have commited some rookie mistake (underinflation, no rim strip, improper mounting, etc.). They can't conceive of circumstances that would lead others to experience flats when they have not. I have to admit that I bristle under this blame-the-victim mentality.

Now, philosophically, I am inclined to say that flat tires are a natural product of the society in which we live and that the only recourse is for each of us to accept shared responsibility and get on with the ride. My lower nature, however, demands a place to lay the blame and point fingers. To that end, I would like to tap the collective experience of this group and try to identify the factors that lead one person to suffer frequent flats while another gets off scot-free.

So, with apologies to those who have ridden 20,000 miles over streets paved with broken glass and goatheads without experiencing a single puncture, I would like to begin the following pneumaticodicy (like theodicy, but with tires).

I'm going to begin by dismissing cheap tires and poor technique. Obviously, running underinflated $10 tires will lead to more frequent punctures, though I'm sure there are those who get away with even this.

I'm also going to assume that not everyone is running Schwalbe Marathon Plus tires with Slime-filled thorn-resistant tubes and tire liners. If you're willing to make your tires heavy enough, you can make them nearly(!) flat-proof. Still, there are many who have good results with other tires.

I'll begin with myself. I've run the following "puncture resistant" tires:

700x25 Continental Gator Skins -- Approximately 6 punctures in 2200 miles, only 1 prior to 2000 miles
700x50 Schwalbe Marathon Supremes -- 1 puncture in 1065 miles
700x28 Panaracer RiBMos -- 3 punctures in 2050 miles, only 1 prior to 2137 miles
700x25 Maxxis Re-Fuse -- 0 punctures in 878 miles

So those are the kind of tires I'm considering.

Looking at my own history, four things jump out at me: (1) most of my punctures have happened on tires with more than 2000 miles on them, (2) most of my punctures have happened when the roads were wet, (3) most of my punctures have happened between late April and early June, and (4) most of my punctures have happened on roads with bike lanes.

Wet roads are obviously a major factor. Someone on this forum suggested the following experiment: Press a dry knife against a dry rubber band and see how far it stretches before it cuts. Next, repeat that under running water. It's surprising.

High mileage seems like an obvious factor, but the tires I'm using do not appear to rely on thick tread as their primary method of stopping punctures. Between the "2000 miles" factor and the "spring" factor, I'm not sure which is cause and which is symptom. I seem to always be using tires with 2000 miles on them in the spring -- an artifact, I suppose, of when I replace my tires.

Spring doesn't seem like it should be a factor, but perhaps it is. It rains constantly here in the spring, but it also rains constantly in the fall and winter, and in the winter I can't even see the road debris to avoid it. I can only conjecture why spring is my bad time for flats. Is it (a) coincidence, (b) warmer temperature is a factor, (c) more auto accidents and/or broken bottles in the spring, (d) local road cleaning is less frequent in the spring, (e) more constant rain in winter washes debris away. I don't know.

That leaves bike lanes. I think this one is a very under-rated factor. I've been noticing lately that while the bikes lanes I ride on are lousy with debris, the auto lanes are strikingly clear. Broken glass in the auto lane quickly gets ground to dust or kicked onto the shoulder. Broken glass in the bike lane stays there until picked up by a bike tire or cleaned up by the monthly street sweeping. If you ride primarily on roads with no bike lane, you may not realize just how absurdly bad the typical conditions of bike lanes are. You don't know how good you have it with your poorly paved rural roads.

So, that's enough from me for now. Now it's your turn to pontificate. How does what I've described match your experience? What factors have I missed? If you're the type who never gets flats, please weigh in with as detailed of a description of your tires, riding conditions and kharma-related behaviors as possible.

That's a major reason I avoid bike lanes...

I got a flat on Saturday. With kevlar tires, I don't carry a spare tube, so it set me back about two hours to walk far enough to get change for bus fair, then to catch a ride to a local bike shop. It was pretty disappointing. On the other hand, the tire has plenty of miles on it, and it'd been raining on and off that day ( and heavily the few days before ), so, to some extent, this seems to match your own experience.

I tried the nasty slime on my last bike, which did prevent flats, but also seemed to gunk up my valves.

Some interesting observations.

Wet definitely affects it. A friend did 600 miles in constant rain on a motorcycle, he commented how the fact that the roads were thoroughly washed allowed him to corner with impunity, because there was almost zero risk of debris or oil. On the other hand, an almost new set of tires needed to be replaced at about 1/3 their expected life. I believe technicians hand cutting racings tires do so using water.

I seem able to pay attention to areas of debris on roads I ride, have often avoided heavily strewn areas. Don't see others doing the same?

My friend and I ride together a lot and tend to use exactly the same tires. He gets at least 5:1 more flats than I do. My explanation is that he doesn't pay attention to where he rides I do. Although it's something I don't think about when riding alone....when I ride with him I notice he often rides along parts of the road or trail I don't use.

I tend to use high quality tires, but not particularly flat proof. I average about 2-3 flats a year.

Cheap tires aren't always that bad. I put few hundered miles on my kenda kwests 700x38, riding over all kinds of crap and no flats as yet. I have also put few thousand Km's on my Conti Touring Plus and Pasela TG's and the only flat I had was a big industrial staple. I am happy with cheaper tires.

*Channeling Sylvester the Cat* I am speechless!

SF

My experience - depends on the compound. Some tires are flat magnets and tread looks nearly intact, some have accumulated micro-slashes every which way and hold up for couple of thousand of miles.

I will never use Boroughs again - no flat resistance at all. I will never use Armadillos - my friend complained about dismal wet traction. So far I am happy with my Conti 4-seasons - good all-around tire for me and my route. YMMV

SF

I believe that the route has much more to do with punctures than do the actual tire. I roll with 700x32C Michelin City, a 700x23C Michelin Orium, and a 26x2.0 Forte VersaTrac (out of production). Knocking on wood, because no one should ever talk about their flats as it only invites more, I've had only two flats in the past two years. I installed Slime tire liners on the 26x2.0s with good results, but since I am using the same tires I can't speculate on if the tire or the route is responsible for the lack of flattedness.

I'm scared to post here-- I might jinx myself.

when I bought my curve, both the front and back Big Apple flatted within a month.

A month into my commuting experiment, I started using the lane more and asserting my right to avoid sand and debris. No flats since.

Rain and bike lanes do seem like they are more flat prone for me.

I find flats and bad luck are directly related.

Yesterday, for example: toilet overflowed right before I left the house; more bad luck while riding to the train station [see below], then I accidentally got on a local rather than express train, and finally I lost my fleece jacket somewhere along the way, so I froze on the train.

The bad luck on the way to the station? Three flat tires. Whole story: I had a slow leak, so I pumped up my tires before leaving the house; this apparently caused an old patch to rupture or something. Not exactly unpredictable. So I put in a new tube, first new tube in several months. Got a flat within three miles. Patched it twice; first one failed, probably due to the humidity (well, it was raining). So... I don't really care whether you count this as one, two, or three flat tires. My point is only that this is a nasty patch of bad luck, of which the flat tire(s) are only a part.

Or a sign... or a cause... I don't know. Flat tires are a part of life. Patch 'em and go on.

This is one of the other hidden hazards of bike lanes. I do pay attention to where I'm riding, but frequently I'll be riding along in a bike lane with constant traffic buzzing past me at 35-45 mph when I come across the debris left over from an auto accident. Because of the traffic, I have no choice but to hold my lane. Yesterday, I hit a patch of broken glass about 15 yards long in the morning and a matching patch about 5 yards long on the other side of the road in the evening, both covering the bike lane from one side to the other. There was nothing I could do but ride through it. Fortunately, it wasn't raining, and my Maxxis Re-Fuse tires have maintained their spotless record.

Why?

I don't know, - I never get flats. You must be doing something wrong.

My guess is that a lot has to do with how much sharp stuff is on the roads. The only connection I can see with bike lanes is that having bike lanes enforces riding near the gutter where junk collects.

My last flat was about a year ago. I was mad and figured it was because my tires were past their prime. They are but I put them back on the bike for now because I like them better than the Michelin Lithions I got to replace them. I know that I'm tempting fate but I hope to get another month out of them.

OK, this is very quickly ceasing to be funny. You see that description of glass in the road I just quoted? Well, today it rained and, despite my e-mail to the city's public works department yesterday, it didn't get cleaned up. So, my RiBMos sustained their third puncture in three weeks.

This one was just a tiny piece of glass. I picked it up in the morning and got to work without losing any pressure at all. When I came out in the evening, I was down to about 15 psi. I looked, but couldn't find the problem so I decided to try pumping it up and heading home. About 2 miles in I could fell myself starting to bounce. I checked again and this time with the tire wet I found bubbles and then a tiny little thing wedge of glass, not more than 1/16th of an inch deep. I pulled it out and psssssssss......the last 20 psi bled out.

At this point, I've lost all faith in my RiBMos. Did crossing the 2000 mile mark really do this? Has a bad run of luck caused me to lose faith in a decent tire? Or did I just have a really long run of good luck between 150 and 2000 miles?

Have I mentioned that it has rained 37 of the past 55 days?

BTW, you people just aren't getting into the spirit of pontificating. No wonder Facebook and Twitter have killed the blogging movement.

Couldn't say it better, and I really have nothing to add to this.