Requirements for good fender installation:
Whether you are planning a new bike or retrofitting an old one, fitting fenders takes some consideration. Well-mounted fenders enhance the appearance of the bike, and they disappear when riding – until the roads get wet, when they protect your body and your bike’s drivetrain from the road spray that makes life so miserable.
Poorly designed and/or poorly mounted fenders rattle and resonate, they drip water onto your feet, and they often break prematurely. Sometimes, they even catch on the front tire and send you over the handlebars.
- Clearance (required). Some riders manage to squeeze a fender into a 5 mm gap between tire and frame, but ideally, you should have about 30 mm between the tire and the bridges/fork crown. 20 mm (above) is workable, but if you have much less then you are running into safety risks. On some bikes, it may be necessary to switch to narrower tires when mounting fenders.
- Chainstay bridge (highly desirable): If your bike doesn’t have a chainstay bridge, fender mounting will be difficult. There are work-arounds, such as using a clamp on the seat tube and cutting the fender short, but they are less than ideal.
- Drilled bridges (required): If your chainstay and seatstay bridges aren’t drilled for fenders, then fender installation will be difficult. Ideal is a vertical drilling (above), which allows direct mounting of the fenders. You can get a sliding bracket for our Rene Herse fenders that allows mounting them on a seatstay bridge drilled horizontally for a rear brake.
- If your bridge isn’t drilled, you can drill it yourself and install a rivnut. Rivnuts usually are used to retrofit waterbottle bosses on older frames.
- Equidistant bridges (desirable): When you look at the three photos above, you see that the gap between tire and bridge is the same at the seatstay and chainstay bridges, as well as the fork crown. (The same applies to a fender mounting point on a rack.) This makes it easy to get good fender lines and to install the fenders stress-free, which is crucial for their longevity. If your bridges aren’t spaced correctly, you’ll need to figure out spacers to mount your fenders.
The short summary of the above: As long as you have adequate clearances, you can usually install Rene Herse fenders.
Wondering which size fenders to use on your bike? Click here for our recommendations.