sknhgy 

I definitely get more flat tires when the roads are wet. Here is my theory:
I ride crushed rock roads. There are big chips, little chips, dull chips and very, very small, very, very sharp rock chips. About the size of a match head.
I figure that when it's dry out, my tires just ride over the chips. When it's wet out the little chips stick to the tire and they go for a little ride until they fall off. While they're sticking to the tire from the dampness, occasionally a chip will turn perpendicular to the tire then it will get pushed in to the tube and cause a flat. I can go for months without a flat when it's dry out. The other day it was wet and I got two flats. Couple days before then and a couple of days after I also got a flat. It was wet out each time I got the flats.
Anyone else ever experience anything like this, or am I crazy?

Rev.Chuck

You have it right. When it is wet stuff sticks to the tire, giving it a better chance to work thru the rubber.
Another thing, most flats happen on the rear tire. This is because the front tire will pop stuff up just right for it to go straight in to the rear tire.

biffstephens

I thought it was because the rain drops set the loose rocks up on end when it hits the ground.

I-Like-To-Bike

I experienced the same effect when I used to ride in Philadelphia. Wet tires were like fly paper for all the little pieces of broken glass in the street. Had flats all the time when wet.

papedaler

Two other things to consider. All those little pieces of glass easily end up in the little cracks and crevices in the road, but when it rains the water floats those items to the surface where they can be picked up by your tires.
Also, water makes a good lubricant, as anyone who has ever stepped from a shower onto a tile floor can attest, so a wet piece of glass cuts through your tire like a wetted knife through an ice cream cake.

Rowan

It's mostly to do with water becoming a lubricant to permit sharper objects to penetrate the rubber. Take, for example, a dry knife and try to cut through a rubber inner tube. Then wet the knife and inner tube and try cutting through again. You will find it much easer the second time.

One of the problems with riding a bicycle is that drainage of roads and often MUPs leads to places where we want to ride. The accumulation of detritis means there is a greater chance of picking up some penetrating item unless you steer around it. But then, when the water dries up, the detritis is still there, and we likely ride through it without a thought. Which leads me back to the water-as-a-lubricant explanation.

Garfield Cat

One other thing about the accumulation of debris. Some cities have routine street cleaning with those big street cleaning trucks equipped with those rotating sweepers that vacuum up the debris. For the most part, it works. Other times, the trucks miss the intersections where its higher elevation with very little motor traffic in what I call blind spots.

sknhgy 

I went for a ride today. It was raining.
Guess what happened?
Yup. Glass in the front tire. I was on pavement.
I also saw a copperhead on a fairly heavily used bike trail.

operator

Water acts like a lubrciant. Like cutting fluid helping tools cut/drill/ream/tap ****.

Pat

Well, it seems the same for me too. That is I seem to have more flats on rainy days then on dry days. But I have not kept a meticulous log of it so it is just an impression I have. It could well be that one gets more flats on wet roads than dry ones. But here is another explanation. If I get a flat on a nice sunny day, well I just get out my stuff and fix the flat and off I go. It is no big deal. Now if I get a flat on a nasty rainy day, I have to fix the flat in miserable conditions. Miserable conditions are very memerable. I tend to remember the big misery rides far longer than the nice sunny rides. So I probably tend to remember flats that I had on wet roads longer than I remember flats I have on dry roads. So even though the rate of flats on dry and wet roads is the same, I remember the flats better in wet roads so it seems to me that there are more flats under those conditions. Just a thought.