Strap-on Telescoping Temporary Bike Fender

I have ridden a bicycle many times in the rain. Bicycles without fenders, that is.

The wheels tend to fling water and mud up in the air and onto your back. It is not a pleasant experience.

The front wheel is not that bad as the spray usually hits the frame and is deflected when riding straight. When turning the spray of mud and water tends to miss you.

However, the rear wheel is where most of the 'damage' takes place with a streak of mud and water making a stripe up your back. (If you want to see an example of mud and water thrown up the back of the rider scroll halfway down this article.)

I was looking at some telescoping antennas and had that thought that they could be used to create a temporary fender. A fender that could telescope to make it compact for storage and also adjustable depending on the diameter of your wheels.

So I came up with the telescoping temporary fender!

The fender is not really robust enough for off-road use, but is intended for street use to keep your backside clean.

Supplies

2 - 5-1/2 x 1-1/2 x 3/4 inch pine blocks

2 - Telescoping rods. Antennas or magnetic pickup tools, approx. 33 inches extended (from Dollar Tree Store)

1 - Piece of heavy duty trash bag 5-1/2 x 34 inches.

1 - Red and white self-adhesive reflector tape

1 - Scrap of bicycle tube approx. 7/8 x 2 inches

1 - Contact cement

1 - General purpose adhesive or epoxy

1 or 2 - Rubber bands. Size 64 (3-1/2 x 1/4 inch).

2 - Brass tacks 1/2 x 1/16 inch

Step 1: Cut Wood for Front and Rear Blocks

The wood is cut into two 5-1/2 inch long pieces.

The piece for attaching to the frame has a 1-1/4 inch diameter hole saw used to cut out the half-circle for the frame to fit into. I drilled the hole saw off center and then cut down the width to 1-1/8 inch so the hole was cut into a half-circle.

I cut down the rear block to the same 1-1/8 inch width.

Step 2: Drill Holes in Blocks

Since the frame/seat posts of a bicycle are typically angled rearward, I had to drill the mounting holes for the telescoping rods at an angle so that they would end up being horizontal when installed.. I drilled angled holes into the 3/4" wide side of the frame block.

I drilled blind holes into the rear block (1-1/8" width side) so that the tips of the telescoping rods could be glued in place when finished.

Step 3: Test Fit Telescoping Sections

I used telescoping magnetic pickup tools for my telescoping rods so I had to cut off the plastic molding to expose the base of the rods.

I test fit the components together so that I made sure that the rods were angled properly and parallel. I actually had to modify one hole and use a shim to get them to align.

Note: The cutout on the frame block is shown facing the wrong direction. If assembled as shown the block could not be mounted to the bike frame as the cut-out was facing inside the area outlined by the rods and blocks.. I reversed the frame block so the half-circle cut-out was facing forward before final assembly. Glad I caught that one!

Step 4: Spray Paint Wood Blocks

I found a dowel that fit into both blocks' holes that helped to hold them for stray painting. I sprayed them flat white.

Step 5: Install Reflective Tape

Since the fender might obscure the rear reflector I placed red reflective tape on the rear-facing surfaces. I also placed white reflective tape on the side surfaces.

You can't have too much reflective tape on a bicycle.

Step 6: Cut & Punch 'Accordion' Plastic

The actual protection from mud and water is a 5-1/2 x 34 inches piece of heavy duty trash bag. After cutting it to size I used a paper punch to punch holes about every 4 inches down each side.

Insure the holes on each side of the strip line up so the telescoping rods look symmetrical passing up and down through the plastic.

Step 7: Install Rubber Padding and Fastening Pins

I didn't want to scratch the frame so I cut cushioning pad out of a scrap piece of bicycle inner tube.

I made sure it was cut so that it would extend slightly beyond the wood block in every direction. I glued it in place with contact cement.

Use a hammer to install the tacks onto either side of the frame cutout for the mounting rubber bands.

Step 8: Thread Plastic Sheeting Onto Rods

I attached the large ends of the telescoping rods and then threaded the trash bag over the small ends.

I alternated the direction of the rods into the holes so that the rods were alternately on top and underneath the trash bag.

Step 9: Mount Fender to Bicycle

The frame block with the half-circle cut-out is pressed up against the frame with the inner tube padding making contact. Rubber bands are then wrapped from one pin (tack) to the other to hold the block firmly to the frame.

I wrapped one rubber band from one pin around the frame, over the second pin, and then back to the starting point. As shown I only wrapped a rubber band over the top of the block. I should have used a second rubber band and wrapped it around the bottom of the block to make sure the fender did not move up or down.