I wanted to extend my front fender to get more protection from road grundge so I cut out a section of an old gatorade green plastic bottle , spray painted it and used chicken straps to attach it. The bottle
has the same arc as the fender.Hope that helps.

Cristoff, I did the same thing with some bottles I found at work. The only thing I didn't like about it was I got a 'parachute' effect when going down hills or when the wind would blow. I did this on my next mud flaps. They are made from a truck inner tube found on a bike ride. I put a little style in it but any shape would work. So far so good.

I made mine out of a narrow side of a black 1qt Valvoline oil bottle. the neck fits well with fender. No parachute affect and light as a feather. Looks store-bought.

Thanks for the pics jharte. What size bolts did you use and did you use lock washers.

vrkelley, thanks for the reply. How did you attach the flaps?

I drilled 2 vertical holes and then used a zip tie Then on the side facing the road put a .5" strip of DOT reflectant. Now if only I could figure out how to keep the grung from accumulating between the fork and the wheel (and sanding down the tire)