Prevent dirt form getting on you and the chain with the help of a fenders made from an worn out or damaged tire. This project used a damaged road bike clincher racing tire as a road bike rear wheel fender. Used, road side recycled, wire to attach the fender to the bike frame. Tire fenders are somewhat camouflaged, as it is tire looking, at first glance.
Using a tire from the same bike type is a good start as the fit is closest. The radius of the old tire needs to be larger when used as a fender so to fit over the present tire. The bead of the old tire bends to a larger fender radius only if the recycled tire rubber part is shortened by dimpling, by a wire spreader. The spreader holds the tire fender wider and dimples in the rubber making the old tire wider and a larger radius of curvature. Customize as needed.
Step 1: Cut an Old Tire for Use As Fender
Decide on how much of the tire is used for the fender and cut it using Tin Snips or any other scissors that can cut the tough steel inside the tire bead.
Step 2: Make Wire Tire Fender Spreaders
Use steel wire (I found mine on the roadside) into the shape shown. It hockes the tire bead wider and dimples the tire rubber.
Step 3: Apply Your Wire Spreader
Put the wire spreader over the tire, don't crimp it at the bead yet as you might want to adjust the fit. In this case you also see the tire damage that inspired recycling this tire into a fender.
Step 4: Put the Fender Over the Bike Wheel
In my road bike case the tire fender fits under the brake levers as shown. Use wire, bent to hook over the bike frame. I put the wire hook part on the bike frame piece holding the brake. In my case the hook is over the horizontal bar. It pulls up by hooking the tire bead. The tension adjusted to hold the tire fender up against the inside of the brake levers. I found the tire fender did not interfere with my brake, you should check this to be sure. Adjust tire fender spreaders as needed.
Step 5: Secure the Fender at Ends
Here the fender is attached to the frame. I bent the wire of the tire bead into a hook. I held this hook to the bike frame using a wire tie from a loaf of bread.
Step 6: Wire Tie the Tire Fender End
The other end of the tire fender was wire tied using "road side" wire.
I will be testing to see what issues come up in this concept. If you do similarly feel free to post your experience as we improve on recycled tire fenders. It would be interesting to know the origin of dirt that gets on the bike chain. I am motivated to protect the chain from dirt via duct tape and cardboard. This material allows easy prototyping, the difficult to design, construction. My overall investigation is a longer term guarding method to prevent dirt from ever getting onto the chain and gears.