“Po’ Boy” Fenders and Other D.I.Y. Projects

Not long ago, I finished rebuilding an old Trek for my weekend fast commuter. Once I had it all together, I realized that the frame- to tire clearances were pretty tight, and there were no mounting eyelets on the frame or fork for fenders. There was NO WAY a traditional set of fenders was gonna fit on this baby! Normally I reserve this bike for sunny days when I don’t have anything to carry, but I wanted a bit of protection just in case I got caught out in the rain…nobody likes “swamp ass” or a muddy stripe running up their backs!

Inspired by the beautiful wooden works of art that Fast Boy Fenders makes (the “Stubby” series in particular) and also inspired by the wacky and wonderful D.I.Y. creations of Kent Peterson (“The Coroplast King”), I got to work scrounging up some goodies to make my own stubby-style fender.

First, the raw materials:
raw materials

I had a few pieces of aluminum strip stock floating around in my shed, and I “liberated” a sheet of corroguted plastic (“coroplast”) from the myriad illegal signs that litter my neighborhood. Election season is a good time to harvest coroplast…especially before the losing candidates collect their no-longer-needed signs. A can of spray paint and a roll of 3M double-sided foam tape rounded out the materials I needed to get started.

I cut a length of the aluminum stock and bent one end to clear the sidepull calipers of my bike. I then bent the entire length to the same radius as a 700c wheel. Finally, I drilled a hole in one end and mounted this aluminum “spine” underneath the brake arms — the drilled hole needs to be big enough to allow the brake mounting post through.

Here is the “spine” mounted and ready to receive the fender:

Using a utility knife and a long straightedge, I cut a section out of the coroplast sheet, spray-painted it to match my bike’s frame and mounted this piece to the aluminum spine with double-sided foam tape. Here’s the finished product:

finished fender

The entire assembly weighs about 2 oz. I could have made it even lighter by shortening the aluminum spine or drilling it out or by narrowing the fender piece — coroplast is fairly rigid on its own, but until I rode with this attached I wasn’t sure how stable the thing would be. Besides, I wanted good rain coverage. Sure enough, this thing works like a charm…it bobs up and down a little bit, but is otherwise totally stable. It IS a bit “hoopty-looking” (frankly, it looks like a piece of spray-painted cardboard up close), but for the princely sum of $0.00 I now have a little bit of splash protection for my rear end.

Speaking of hoopty-looking D.I.Y. projects, I discovered to my dismay that I have run out of handlebar room on my Euro-style “Grocery Gitter“. The basket mounting brackets took up the last bit of room, and I was struggling with a way to mount some bike lights to the basket. Suddenly, I remembered a few lengths of 1” schedule 40 PVC pipe that live under my house. I crawled under the house and retrieved a dirty, scratched-up length. I drilled a couple holes in the pipe, threaded it through the front of the basket and ziptied it into place. The two Serfas lights I wanted to use now mount to the ends of the pipe using the original handlebar clamps.


The lights are separated just enough that now I’ve got a nice wide patch of light in front of me at night (I just took this bike to the grocery store and back to test the light pattern). Hoopty it may be, but this and the fender project cost me absolutely nothing…that’s the best kind of project at all! Function over form in both cases, too, but a little bit of creativity could make something a bit more sleek and glamorous…

more lightbar


  1. RL

    Wow I like that fender idea!

  2. kim

    Three cheers for hoopty bikes!

  3. Ghost Rider

    Thanks Kim! It’s how I roll these days…

  4. Quinn

    I did kinda the same thing with a front fender, I was looking for fenders for my 29er, I didn’t want the PB Cascadia’s, so I got a steerer-mounted (star nut) 26″ Apex, the radius fit perfect, a lil short narrow, so I took cardboard from a snack cracker package and a roll of electical tape, and built it up to look like a T.H.E. fender.

  5. Marrock

    You know, I do have half a sheet of black coroplast to play with, it’s nice having a sign shop just down the road, I just need to find something to make the strut from.

  6. Val

    Excellent light mounting technique! I have a suggestion that may make it even better; worth a try, anyway. It occurred t0o me that if you were to fall (god forbid, but it’s always possible), the lights would be the first thing to hit the ground. If you use a slightly shorter piece of PVC, it could be ziptied to the underside of the basket, with the lights mounted upside down below it. This way, they would be protected, and still have nice separation. The PVC would no longer impinge on your cargo space, either (not that that is a serious concern). Baskets are great places to mount accessories.

  7. Ghost Rider

    Val, I actually tried that method first…I couldn’t get the zipties tight enough to keep the PVC pipe from rolling and messing up the aimpoint of the lights. Perhaps a U-bolt type clamp would work?

    In any case, I’m gonna play with this a bit. I sure don’t want to smack my lights on the ground!

  8. Smudgemo

    Nice! I was just thinking the other day about mounting my helmet-mount light somehow to the front rack on my commuter. Then I wouldn’t have to carry the battery and it would be below the rain cape I’ve got on rainy days. Mounted on the handlebar, the lights get covered by the cape.

  9. Val

    Jack: Maybe two zipties through each hole, running to either side of the tube, to provide triangulation adn stability. Just a thought…

  10. Marrock

    You could also notch the PVC so the wire of the basket slots into the side of the pipe.

  11. Ghost Rider

    Ah hah! I will try both of those techniques next time I tinker with it.

    I only lost a couple inches of carrying room — two gallons of milk still fit in the basket. That’s plenty of room for me!

  12. Ben C

    Here is an idea:

    Get a thin retancular piece of metal. Drill a hole in the middle. Make the metal piece long enough to trap two bars on the basket. Put it horizontal and screw a hole into the PVC using the hole in the piece of metal. That should help from the PVC rotating.

    Home depot sells a small bag of these metal pieces. They look like a strip of metal. Just and idea.

  13. Max

    When I worked at Keystone ski resort in the early 90’s a friend of mine rode his Specialized to work every day, snow or shine. We took a ski cracked towards the tail and cut off the first 2 feet of the ski, flipped it upside-down and mounted it over his rear tire by way of the seat-post. It looked so cool, and the ski manufacturer logo was visible thru the clear p-tex layer on the ski-bottom. Everyone kept asking him where he bought it. I wish I had pictures…

  14. Ghost Rider

    The ski tip idea is cool — I’ll have to keep that in mind (except skis are hard to come by in Florida)!

    I originally tried one of those clip-on fenders that clamp around the seatpost, but I didn’t have enough room on the post for the clamp (blinkie and seatbag got in the way). I even tried to thread it through the seatstays to clamp on the seattube itself, but couldn’t get anything beyond a crazy upright angle.

  15. Marrock

    By th way, if you work with coroplast a lot these can be invaluable.

    They’re cheap, reusable, easier to work with than duct tape and look cleaner than zip-ties when in place.

  16. RL

    Around my neighborhood, I saw a bunch of “Ron Paul” signs that would be perfect candidates for fenders and other projects…

  17. welshcyclist

    I like the headlight idea, and could be very useful to myself in the near future, but, and there’s always a but, isn’t there? I’m totally inadequate when it comes to DIY, but I think I’ll give it a go. Cheers and thanks for publishing these ideas of yours.

  18. Pingback: Post Consumer Fenders « Bitratchet

  19. Raymo853

    You basket light mount is so simple and shames me for not thinking of it on my own. One other benefit, when the basket is full of groceries, the lights are not blocked when on the bar.

  20. Hermes

    dude that was awesome!

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