Fender Reinforcement Plate

Metal fenders are great, and they can last for ages.  But they have to be mounded correctly, and properly reinforced at critical flex points or they'll get cracks.  Fenders often fail in one of two places: fork crown and seat stay bridge.  Stick these adhesive fender reenforcement plates UNDER the fender, and mount thru them.  You further beef the area up by adding a washer between the bolt and fender.  

We have M6 and M5 washers here + M6 and M5 bolts here.  More fender hardware can be found in the small bits collection, including leather washers, mud flaps, stays and more.    

Two sizes, two plates per package.  The narrower one is 30mm wide, and ideal really for fenders between 40 and 35mm wide.  The wider one is for most other fenders.  Not all fenders are round but you can reshape these fairly easily by putting them on something hard and pressing down with a chunk of wood like a 2x4 scrap to flatten them out a bit.  You can trim them with a dremel if needed as well.  Mounting metal fenders is always a pain in the butt, and often you have to engage in some degree of hamburglary to make stuff work.  

Lightly sand the area where you're gunna stick the fender with some 400 grit sand paper or at the very least some steel wool.  Wash with denatured alcohol, then you can stick these in place.