Urban cycling tip of the day: Fenders are like screw-top wine

Well, the rains have crept back in on little cat feet. And they’re sure to be freeloading on our couches for the next six or seven months before we’re rid of them again.

So in an effort to be more useful, we proudly launch:

The Urban Cycling Tip of the Day

(Which in no way implies there will be a tip every day.)

Today’s tip: Fenders are like screw-top wine. Which is to say: Get over it.

I know, some of you have no problem with fenders and have used them for a long time. You people can go about your business. It’s the rest of you I need to speak with. For I have a personal story of tragedy and redemption, which I’ve actually told before.

Short version: I used to look down on fenders. I thought them for people who were not serious about cycling. Then I hit bottom: wet, soggy, reduced to panhandling on street corners in order to buy more and more expensive rain gear. Then I got fenders. I put my life back together. I expect to soon be elected president of the United States. Or at least get my own TV talk show.

So how are fenders like screw-top wine? Well, in some circles, putting fenders on your bike sucks the romance out of pretending you are winning the Tour de France while headed to work, just as twisting open a bottle of screw-top wine takes the romance out of your efforts to seduce that lovely person you have just lured back to your apartment.

But it turns out that screw tops are actually better for the wine. They did one of them scientific studies. Likewise, fenders keep your butt dry. (Which is also better for seducing people.)

Not long ago on Twitter, I had asked for some suggested topics for blog posts, and someone responded: “How it’s the bike not clothes that matter in the rain.”

I puzzled over this awhile. I think what the person was talking about here — and he can correct me if I’m wrong — was the humble fender. The idea that a lot of the water that ends up on you comes up off of the road, not down from the sky.

It’s true. But it is more complicated than that, because we cannot deny that rain comes down out of the sky. This has been proven.

How dry fenders will keep you will depend on many variables. Through rigorous scientific study of our own, we are now able to calculate the value of “wetness upon arrival at work” through the following equation:



  • w is wetness upon arrival at work
  • d is duration of your commute
  • i is intensity of the rain storm in inches per second
  • Δi is the change in the intensity of the rain storm during the commute
  • Θ is the angle of the rain, varying from straight down to sideways
  • f is the fender constant, equal to approximately -1.647893695657676
  • Φ is the constant “phi,” which indicates whether or not your route includes any gargantuan puddles caused by clogged storm drains — and is also what you say when you encounter them: “Phi!”


  • Ω is the resistance of your clothing to water passing through.

Because rain gear of some kind does matter. At least a coat. But like this guy, whom I spotted this very morning:

A poncho and fenders — and a pair of jeans — may be perfectly adequate for a short commute in a mist, drizzle, spotty showers or even light rain.

But what is more important is whether you will ride in the rain at all. Which is why — when I responded to that tweet — I suggested maybe it’s about neither the bike nor the clothes, but that “Maybe it’s about the person.”

And so we can calculate the probability of whether you will commute by bicycle by the following, known as the Heisenberg temptation formula:



  • b is the probability of commuting by bike
  • ƒ is the fortitude and self-righteousness of the commuter
  • w is the wetness factor, as calculated above


  • c is the presence of a warm, dry car in the driveway.

So resist! Be strong. Stay dry. Buy fenders. Ride.

18 thoughts on “Urban cycling tip of the day: Fenders are like screw-top wine

  1. My eyes just glazed over when I saw all those equations… or maybe that was rain in my eyes.
    I agree- the c factor in the Heisenberg temptation formula is very important!!

    And yes, I meant fenders… but also chain guard, upright riding position (which makes even an umbrella possible. Don’t laugh.), built in lights (rainy season is usually dark season, think battery free, screwed on generator style) and a basket/rack to throw your bag in so it doesn’t have to go under rain gear (hard) or over it (wet) and a simple plastic bag over it to keep it dry (if not already waterproof). In other words, get yourself a city bike (or dutch style) and you’ll be that much more comfortable pedaling in the rain… even in semi-regular clothes.
    I ride in a rain jacket that I can wear anywhere/anytime and not feel like a traffic cone. I carry rain pants that I use about 1 out of every 20 trips in the winter. Gloves I use are for cool/cold days and rain. No helmet cover, just the wool cap I also use on cool days. I have ‘galoshes’ (Burley shoe covers) I use about 5 times a year for the serious downpours I can’t just wait 15 minutes to pass.

  2. Whatever the equation, in my opinion you FEEL about 90 percent dryer.

    Except for the feet. The best of fenders can throw buckets of water on your feet.

    But some plastic bread bags under the booties and yer good ta go!

    Is there a wet factor equation for milk crates? Just curious.

  3. What a perfectly coincidental & well timed post…my bike is in paul’s right this very moment and-in addition to some new brakepads, i wondered “to fender or not to fender?” well I think, after reading this post and re-reading the summer post on the rain issue ( i was so young and innocent then..) and sitting in class for the umpteenth time soaked that fenders are the way to go!

  4. my c is huge.

    not only is there a warm dry car in the driveway, but my wife drives it to work in front of the very same building that I would be riding to if I wasn’t heating my butt on the seat next to her.

    I would say that I feel shame, but what I really feel is a deep longing for the self righteousness that I’ve lost.

    The funny thing is that when I have ridden in, it’s generally when the weather is a little worse and it makes me happy that I get to take advantage of my cool rain gear.

    I also converted my drop-bar do-it-all cross check into a city bike after getting a real cross bike. I ended up realizing that somehow the more upright position actually hurt my back and that I kind of missed having a drop-bar bike that can handle fenders and a rack.

    1. There is a happy medium- too upright and your spine is unduly absorbing the immaculate smoothness of Eugene’s streets. Having a bit of arch lets your back and arm muscles pitch in to take the shock.

        1. Nice! I only have clearance for a rear clip-on, but have been trying to fandangle a front fender recently. Toe overlap isn’t especially conducive to a front fender. For now, I just put on the booties if I want to keep my feet dry when it’s ultra wet and clean my drivetrain regularly. I’ve been happy doing it that way the last few years.

    2. Don’t feel shame, Kevin. But, yeah, sometimes I think it’s really fun to ride in the rain — like last night. I got poured on. But it’s always more fun when you are on your way home and you know there is a shower/change of clothes/fire/cup of tea etc. waiting at the other end.

      Different story when you are on your way to work.

  5. It blows me away that people in wet climates could be anti-fender.

    Also, science says there is no substitute for cork when it comes to aging wine. Some day, hopefully…

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