No Mudflap: What a Mess!

dirty_GBU

Just one week of riding without a mudflap, and look at my bike! It’s a mess!

I ride my Urban Bike year-round in rainy Seattle, but thanks to its generous fenders, it rarely gets dirty. I clean it only once a year, because it doesn’t need it more often.

Then, last week, the mudflap on the front fender came off when I reversed the heavily loaded bike up a home-built ramp out of the basement. The flap got caught underneath the front tire at the end of the ramp, and pulled out of the fender.

GBwhitetires

It’s surprising to me – the front fender is as good as they get: It extends as low as it can without hitting curbs. Yet without the mudflap, spray hits the bottom bracket and entire rear of the bike, to say nothing of my feet. And with the rubber mudflap (above), the bike stays almost totally clean.

This experience shows once again how important those “minor” details really are. This weekend, I’ll install the mudflap again!

About Jan Heine, Editor, Bicycle Quarterly

I love cycling and bicycles, especially those that take us off the beaten path. I edit Bicycle Quarterly magazine, and occasionally write for other publications. One of our companies, Bicycle Quarterly Press publishes cycling books, while Compass Bicycles Ltd. makes and distributes high-quality bicycle components for real-world riders.
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38 Responses to No Mudflap: What a Mess!

  1. Rod Bruckdorfer says:

    What brand and model fender is fitted to your Grand Bois urban bike? Are the fender constructed from aluminum or stainless steel?

  2. Willem says:

    Something similar happened to me the other day on my 1988 Koga Miyata commuter bike. The old plastic mudflap had become brittle after 25 years, and tore in two, with even worse results. Mudflaps are a necessity.
    Willem

  3. tim potter says:

    Great article. Rear mudflaps are seldom talked about. They are definitely a good thing for riding in groups and keeping your friends from complaining about getting sprayed with mud in their faces. Of course going without one may also help keep wheel suckers off your rear!

  4. RickH says:

    I totally agree. I have been riding a recumbent where initially I was getting covered in dust and grit thrown up from the back wheel into my helmet even on a dry, clean looking road. I realised how much a drive train is prematurely worn with this debris thrown into it all the time. How much worse in wet conditions.
    Mudguards/fenders please. Not just to keep the rider cleaner.

  5. Heather says:

    How fitting! I just came home and told my husband about my front mudflap experience and he said oh Jan Heine just wrote about his! I recently got leather mudflaps on my current commuter. They are standard sized. The fenders are those cute but not 100% useful old raleigh fenders which are not very long. I also think the tires are too wide for the fenders. I finally got caught in a downpour to test the front one out(my husband already confirmed that the rear helped enormously with stopping grit landing on his face). I can now see how mudflaps are supposed to work but having biked through puddles just earlier I can say they really do need to be long, almost to the ground, and in this case, should be much wider! The water slopped around the sides and hit my toes, but did stop water from hitting the drivetrain. I enjoyed watching the mudflap scoop through the puddles, but could see I had a problem.

    • A longer mudflap can only partially “fix” a fender that is too short. When it rains hard and you go fast, the mudflap just moves out of the way. A shorter mudflap, especially if it’s made from rubber, keeps its shape much better. Really, it should be called a “flexible fender extension,” since you don’t really want it to “flap.”

  6. Joe says:

    I’ve been wondering lately if there is an ideal distance for the fender to be above the ground, as well as the mudflap. Right now my mudflap occasionally hits the ground going over speedbumps or off curbs. I also wonder if having the fender curve inwards at the bottom causes it so scoop up more water. Any thoughts?

    • Fender: The height of the larger curbs in your area plus 1″ (2.5 cm). Mudflap: I don’t think it needs to hit the ground, but it shouldn’t be more than 4″ (10 cm) off the ground.

      If your fender actually scoops up water, it must be very low, or you ride through very deep water.

  7. One other thing to consider: All the spray from your front wheel is collected in the fender, and then runs back down to the trailing edge. There, it drips into the spray that comes off the front wheel, and much of it is incorporated into that stream. So it may well be that short fenders get your feet more wet than no fenders at all, since they concentrate all the spray into a steady stream. (Or course, your knees will stay drier…)

  8. Franklyn Wu says:

    What type of rubber mudflap do you use? Is it a off-the-shelf product that you can easily procure from a bike shop?

    • I make the mudflap from rubber gasket material. You buy it in hardware stores in sheets that are large enough for 3-4 flaps. Price is about $ 7 per sheet. I don’t recall the exact thickness, but it’s about 2-2.5 mm.

      I cut a flap from cardboard and insert it into the fender (after I open up the rolled edges of the fender a bit). Once the cardboard template is the perfect shape, I cut out the rubber to match. I keep the cardboard template for future reference.

      I insert the rubber flap in the fender, and then close the rolled edges with pliers so that the flap is locked in place. To protect the finish of the fender, I put a little piece of wood between the plier jaws and the fender when I crimp the rolled edge.

      • DaveInGlenshaw says:

        Or you can use black rubber cove molding from Home Depot or Lowe’s, $4.00 per 4 feet. Mount the same way as Jan.

  9. Benno says:

    I’ve found that a rubber mudflap can be too close to the ground and not only hit the ground occasionally but sticks that are thwon off by your tire will be scooped into the fender by the mudflap, which can be quite dangerous. It seems like a good rule of thumb is that if any part of your chain has line of sight to the contact patch of your front wheel (when the mudflap is fully extended) you will get spray on your drivetrain. If your fender/mudflap is set just at this point, you should be okay and still have clearance for debris.

  10. wycheproofs says:

    Yes, mudflaps are very important for rainy rides. I’ve made my own from discarded plastic bottle. I’m looking at your pic and I see that your mudflap is following the fender and wheel line. I just wanted to add that if you place the same mudflap vertically, pointing straight to the ground, it’ll have larger area of active protection. Maybe the aesthetics will be compromised but I think its worth to try.

    • You are right, a mudflap that goes straight down does offer more protection – at low speeds. When your speed increases, you have both wind resistance and the water spray off the wheel pushing the mudflap back. A short, curved mudflap resists that force very well. That is also the reason why leather mudflaps aren’t so useful. The leather gets wet and very soft, and then the only thing holding it in place is gravity.

  11. Kathryn says:

    How far into the fender should the mudflap extend?

  12. Bill Pustow says:

    Jan, you had an excellent article (with photos) on this very topic in BQ. Do you remember which issue?

  13. Bill Pustow says:

    Bay the way, I have long Honjo’s on my new Herse and did not think I needed mud flaps. Well, last week I rode though a few puddles on our Kentucky farm roads and YUCK! I’m now a believer

  14. Bert says:

    What are your chainring sizes? The small one looks tiny in comparison. How do you get it to shift ok? Thanks.

    • Ryan uses a 48-32, Hahn has a standard “compact” 50-34. They shift great with any normal “double” front derailleur. I believe Ryan’s is a Shimano Dura-Ace, Hahn uses some SRAM derailleur. My own bikes also use a 48-32, one with a Huret Jubilee, the other with a hand-made Herse front derailleur.

      • RickH says:

        I ride with a 46-30 chainring and 11-28 10 speed rear driving a 700c wheel. It covers almost everything I need except when I’m tired, grinding up a 22 kilometre 6-9% hill and wishing “just -one -more -gear”.
        Of course, when fresh it’s different.

  15. Paul Ahart says:

    The other day I installed a set of SKS Longboard fenders on a customer’s Gunnar Crosshairs bike (she is doing Land’s End to John O’Groats in April) and found the rubber front fender flap nearly brushing the ground, where it could scoop up debris into the fender. Using a heat gun I softened the flap while bending it back a bit, allowing about 4 cm clearance from the ground, and making it hang straight down or back a bit. The rubber is quite stiff and should do the job well. Just getting this person to install fenders at all was like pulling teeth. I’m sure she’ll love them.

  16. Kathryn says:

    how wide is the flap at the bottom.

  17. Doug Peterson says:

    The front rack on the urban bike is especially nice looking. What brand is it?

  18. Norman Bone says:

    That’s a mess? Take it easy there, Howard Hughes. You’re not eating off of that. Some dirt adds character.

    • You’re not eating off of that.

      I am not eating off it, but my feet, my chain and my bottom bracket prefer to stay dry and clean. I am not afraid to get my bike dirty – I ride in the rain, on gravel, etc. – but I don’t like creating a preventable mess. (I also take off my muddy shoes before I enter the living room.) Adding a strip of rubber is simple enough…

      • Slop Sink says:

        It’s simply that it isn’t really THAT much of mess, just a little bit dirty in a small area, so your language seems almost hyperbolic. Of course, being used to a relatively clean bike, you are surprised at the new filth collection.

  19. Mic Hussey says:

    Over here in Sweden we call the rear mud flap the “kompislapp” (flap for your friends) and the front mud flap the “egolapp” (flap for your ego).

  20. Mike A says:

    I also have the SKS Longboards on a bike. The way that the front mud flap is mounted is such that there is a lip at the fender/mudflap joint, which acts as a ramp that launches the water coming off the tire. With a smooth joint, the water would run up the inside of the fender and eventually drain back down. This is sort of like the effect that Jan pointed out somewhere of the mounting brackets which, since they extend across the inside of the fender, form a dam that diverts the water from running down the fender. I often ride in the rain and have watched these effects. The mudflap effect would not be as bad if it extended down more vertically, rather than wrapping around the tire near the bottom.
    I also have a bike with VO full fenders. I think these are a bit better. I could improve things at the rear fender/chainstay bridge interface. I have it zip-tied there.

  21. Brian says:

    I saw a photo of your custom Rene Herse and noticed that you did not have a rear mudflap.

    Is it because you always finish first? ;)

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