Tuesday, August 26, 2008

The fallacy of water resistance

Date: Aug. 26
Mileage: 61.2
August mileage: 624.9
Temperature:
51

The argument about what clothing barrier will best protect a cyclist from falling precipitation while simultaneously rejecting inner condensation will go on until the end of time. I say such a garment does not exist. "A rain jacket can't keep out all rain and let out all sweat," Geoff told me once. "It goes against the laws of physics." Now, I haven't taken a physics class since I was in 11th grade. But I have owned a lot of rain jackets ... gortex, polyester, nylon, PVC. The driest by far has been the PVC - sure, it doesn't breathe, so it builds up a lot of inside moisture. But it's a tropical kind of moisture, warm and humid, and just a little bit damp - it's not the kind of frigid soaking I get once my other rain jackets give up the ghost and I'm left alone in the weather.

I feel strongly about this issue so today I actually set out to blog about it. Today's subject: My Pearl Izumi Vagabond jacket. I won this jacket in the 24 Hours of Light. It's a great jacket, actually - it has zip-off sleeves, fits well, retails for about $100. And, in its defense, it is not made for extreme weather. But today did not feature extreme weather. It was rainy and windy - normal weather.

This jacket was brand new on June 28. It has never been washed (I know ... ew). Here we have a picture about five minutes into the ride. See those glistening beads of water? That means the Vagabond is doing what it's supposed to, keeping the rain out. All is well, right. Right?

But here we have the jacket about 1:45 into the ride. Where did all the shimmery droplets go? Could it be that they've bounced clean off? Or maybe the jacket developed an invisible force field to further repel the raindrops that are still falling from the sky. Or is it possible, just possible, that the rain has soaked through?

Let's check ... roll up the sleeve. Yup, my base layer is soaked, at least as far as my elbow. Could it really be an inordinate amount of forearm sweat? At 50 degrees? Or could it be that my fairly new, $100 rain jacket is (gasp) letting in the rain?

Come to think of it, I am feeling pretty soaked. Once this jacket gets pretty wet, it's no longer very wind resistant either, and I can feel the chilled breeze moving through. Luckily, I carry back-ups in my trunk bag ... Polar Fleece. It's not water resistant in the least, but at least it's still warm even when it's wet.

So, my conclusion: Most rain jackets are good for 20, maybe 30 wet rides before they start breaking down. I've tried that spray-on waterproofing before, but mostly found it to be pretty short lived and not really worth the cost. The best plan when the weather is dipping into the 40s and raining: Stay warm. Wool is warm but heavy. Polar fleece is better. But PVC is best, and I usually return to it when I've come to the painful acceptance my latest "water-resistant breatheable" rain jacket just wasn't made for real rain.

If you go out in the rain, you're going to get wet. Accept it. I have.