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Flats in the rain(15 posts)

Flats in the rainMikeC
Oct 1, 2001 12:10 PM
I've always wondered
b why
we get more flats in the rain.
Is it because glass and other debris sticks to tires when they're wet, when otherwise it might just get pushed out of the way or fall off before it cuts through?
Yes (nmi)MisJG
Oct 1, 2001 12:30 PM
It's because...MrCelloBoy
Oct 1, 2001 12:33 PM
It more of a drag to change the flat in the rain!
re: Flats in the rainmr_spin
Oct 1, 2001 12:42 PM
I've never bought the "rain causes flats" theory, because it seems no different to me whether it is wet or dry.

Nevertheless, the basic idea is that the rain floats up debris that slipped below the riding surface. So whatever fell into cracks, pits, holes, etc. now comes up and you have to ride over it.

I wouldn't worry about stuff that "sticks" to your tires. Anything that sticks to your tires but doesn't go through is probably never going to go through. It takes a fairly large amount of force to drive something through a tire (try it some time). If you hit a piece of glass head on, you can force it into your tire (as is proven daily). But, if it only goes part way in, you are safe, because you've already applied near maxmimum force. Unless you apply more force, such as riding off a drop, the glass is not going any further. That's why brushing tires is useless. Not to start that thread up again....
re: Flats in the rainbikedodger
Oct 1, 2001 12:47 PM
Is it possible that the rain acts as a lubricant and it therefore takes less pressure to get the glass sliver or whatever deeper into the tire?

brushing tires & flatsDave Woof
Oct 1, 2001 1:40 PM
I beg to differ. I brush my tires every time I ride through debris, glass, etc and have brushed off a lot of stuff that would have gone through the tire. If you ride through hot sticky tar, gum, or whatever it picks up other stuff. If you can't brush it off you at least know it's there when you feel it with your fingers, and can stop to remove it.

Dave Woof
Read this...mr_spin
Oct 1, 2001 2:28 PM

Read this conversation between Jobst Brandt and Sheldon Brown. Brandt is a very strongly opinionated (understatement) guy who wrote the bible of wheelbuilding, The Bicycle Wheel. Brown is, well, one of the great characters of cycling:

From the day I first saw it done, I thought brushing tires was worthless. When I discovered this article, I realized I was right.
Sounds pretty pseudo-scientific to meChris Zeller
Oct 1, 2001 3:24 PM
Despite Jobst Brandt using pleanty of scientific jargon, I didn't see anything in this discourse to convince me either way. This is not to say it isn't correct, I just think this doesn't settle it.

My initial feeling is with Sheldon Brown. With some engineering understanding of crack propigation I think it is possible for a glass chip to become imbedded in the first few layers of rubber and cause further yeilding of the material with each subequent loading until it penetrates the tire and then the tube. The glass chip would propigate like crack propigation. There are pleanty of examples of this happenning in mechanical systems where cracks are loaded cyclically until failure.

The "tent" formation mode mentioned in the article would only apply to glass chips which are not sharp enough to concentrate the stress enough to cause yeilding. I can't see any reason why a glass chip couldn't act like a nail being pounded in.

I'm sure this applies to a specific range of glass particles, those sharp enough to stick but not sharp enough to enter on the first few rotations. I couldn't begin to suppose at the statistical distribution of these particles. Therefore the practicallity of wiping a tire may be limited.
Read this...Woof the dog
Oct 2, 2001 2:47 AM
i think a piece of glass can eventually cause a puncture because once it gets embedded into the tire, it will slowly move further in due to the tire bending back and forth (when it depresses at the contact with road and then bends back out). It may not happen quickly, but probably by the end of the ride. What can I say, there are many factors that come into play that affect how fast it will flat. Okay, I will stop playing a scientist here. Let me just tell you that I brush my front tire when stuff sticks to it for the purpose of safer cornering in the rain. Imagine all the sand stuck to your wet tire when you gotta make a right-hand turn and you will know what I am talking about. I don't do it often because I don't really ride in the rain and usually the amount of sand on the asphalt is minimal. Its harder to reach the back tire and I don't feel like losing my fingers. There.


Woof the doggie
Don't want to...dzrider
Oct 2, 2001 4:29 AM
I'm content believing that brushing my tires when I run through debris is part of the reason I have fewer flats than I used to. Learning that my experience is impossible won't change my behavior.
re: Flats in the rainmickey-mac
Oct 1, 2001 12:52 PM
My theories are: 1) road debris is often more difficult to see and therefore more likely to be hit in the rain and 2) stuff tends to get washed onto the shoulder of the road and therefore into our path.
re: Flats in the rain, yes.Chen2
Oct 1, 2001 1:00 PM
I was on a ride with 7 people. We were riding on a highway shoulder. It started raining. In a short distance we had a total of 7 flats. One guy had 2. My 200# wife was the only one who didn't have a flat. All of the flats were caused by glass. Before the rain we had ridden through lots of glass without a flat. Yes, I believe rain increases the chances of having flats, but I don't know why.
Oct 1, 2001 4:46 PM
The reason we get more falts when it rains is because roads are made with a slight camber that lets the water run off the road and into the gutter. This mean any debris will gradually wash across the road to the gutter also. As cyclists ride on the shoulder at the edge of the road we ride over all this washed over debris.
Cars do flick debris in both left and right directions, so when it rains it ALL comes back across our path.
err... FLATS not FALTS (nm)Dutchy
Oct 1, 2001 4:47 PM
That's why I ride on the left half of a dual paceline. -NMTig
Oct 2, 2001 8:27 AM