While the subject for discussion is revolving around fenders, their construction, and materials used, I figured these comments from a different blog, same subject, might be useful:
"… When a wheel is moving inside even a dry fender it is producing a pretty decent wind-tunnel effect, which will efficiently and effectively push along any water present around the inner diameter of the fender towards the front, if its course is not disrupted. Any water flinging off of the tire will also shoot outwards on a tangent from the spinning tire and strike the inside of the fender and be warped back by the fender in the direction the wheel is spinning towards the front. The middle of the fender is further from the axle than the sides, so water moving with the wheel will want to channel naturally via centripetal force into the larger radius of the middle of the fender and away from the sides until it emerges at the front of the fender to be spat out in a straight line on a tangent to the diameter of the fender (Newtons laws of motion.) The problems with the SKS fender, and many other plastic fenders like it, are not the lack of the "ridge" at the sides but the fact that the metal fasteners for the stays are mounted on the inside of the fender, where they will cause the smooth flow of water around the fender to be disrupted and cause turbulence in the stream. When the water flowing around the fender strikes these metal obstructions it will splash and spray in all directions instead of continuing to flow around the fender smoothly. One of these directions is right out the sides of the fender to drip onto the stays and/or jump into the airstream of the bike. From there it is "blown" right back out on the rider and the bike itself. Not good. The only real solution to this is to drill out the rivets holding these brackets and to move the mounts to the outside of the fender instead. I've done this on my front fender and it makes a *huge* difference. Water no longer leaks or sprays out the sides of the fender and instead keeps traveling along the length of the fender until it is ejected efficiently out the front towards the ground where it belongs. This brings us to the next problem with SKS and other plastic fenders. They do not have the same rigidity as metal fenders and thus the makers of these fenders do not make them protrude far enough forward to keep the terminal spray from shooting upwards and back into the airstream of the bike, to come right back at it and the rider once it is caught and spread out by the wind. A front fender should cover around at *least* to the top of the tire and continue onwards a few more inches so that the water is ejected in a generally downward direction where it has a chance of making it out of the way of most of the bike and the rider as it catches up with it. Metal fenders often are mounted to the front rack which is installed low and close to the wheel to keep the center of gravity of any load such as a handlebar bag as low as possible, and to also mount the forward portion of the fender so it can extend out and downward even a little bit more. But even without a rack a metal fender is still rigid enough to protrude much further than a plastic one. The SKS longboards, and their chromoplastic cousins have a very short front fender IMHO. If the fender is mounted in front of the fork crown it works a tiny bit better for pushing the water downwards or at least not upwards as it exits the fender, but then it is way too high on the back so spray hits the bottom bracket, cranks, and the downtube even with a mud flap installed. If the mount is installed at the back of the fork crown it is a little better at the back, but it still a little too high to do an effective job -flap or no. The bottom of the mud flap should be about 4" or so off the ground to really do its job and keep most of the spray from the back of the front wheel away from the BB and the rider's feet on the pedals and cranks. My solution was to use a rear SKS fender on the front wheel, which is much longer. I mounted it to my front rack in the "rando" style of the French Constructeurs as well as to the front of the fork crown. This still left enough length to get it low enough in the back to reach down so that with the flexible SKS optional mud flap extends to about 4" from the ground. I had to cut a little bit off of the front of the rear fender because it is shaped to go into the chainstay area of the rear wheel and also miss the chain. It isn't shaped like a front fender. It was pretty simple to cut it with a hacksaw and to file into the same shape as a regular front fender though. These modifications make my hacked plastic SKS fender work just as well as a metal fender with the "ridges" on the side. The ridges are really only there to make a metal fender stiffer, adding "rigidity," so to speak. Having a longer fender without any obstructions on the inside is what is really important, I have found, with my experiment with a rear SKS fender on the front. Relocating the brackets to the exterior of the fender made the water flow smoothly without spraying out the sides at all…." On Monday, April 20, 2015 at 9:10:55 AM UTC-5, Patrick Moore wrote: > > Thanks for this. I don't plan on spending a great deal -- this would be > for very occasional use on the Fargo -- but your photo gives me ideas for > making my own out of coroplast or something similar, though I want coverage > from the bb upward. > > I'd want a QR way of attaching the fender at the chainstay bridge, > probably a "prong" or "hook" that clips to the bridge; a tab at the > seatstay bridge like yours and sufficiently stiff material would probably > do for the rest (I'd truncate the fender just aft of the Pika). > > On Sat, Apr 18, 2015 at 6:49 PM, Jeff Lesperance <jeff.le...@gmail.com > <javascript:>> wrote: > >> On Sat, Apr 18, 2015 at 6:58 PM, Patrick Moore <bert...@gmail.com >> <javascript:>> wrote: >> >>> Can anyone recommend a quick-on and quick-off set of fenders for a 29er? >>> They need not be full coverage, just better-than-nothing coverage; the key >>> is quick on/off. >>> >>> >> How about a Woody's "chop chort" fender? I've bought one from him with >> his standard mount, which you can see on his site here: >> >> http://www.woodysfenders.com/store/index.php?main_page=index&cPath=8 - >> that would probably move out of the way easily enough to manage rear wheel >> removal. >> >> I recently had him make a wider chop chort rear fender, that he though >> might need more hardware to hold solid, so I had him add a standard rear >> stay - picture attached. >> >> [image: Inline image 1] >> >> -- >> You received this message because you are subscribed to the Google Groups >> "RBW Owners Bunch" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to rbw-owners-bun...@googlegroups.com <javascript:>. >> To post to this group, send email to rbw-owne...@googlegroups.com >> <javascript:>. >> Visit this group at http://groups.google.com/group/rbw-owners-bunch. >> For more options, visit https://groups.google.com/d/optout. >> > > > > -- > Resumes, LinkedIn profiles, bios, and letters that get interviews. > By-the-hour resume and LinkedIn coaching. > Other professional writing services. > http://www.resumespecialties.com/ > www.linkedin.com/in/patrickmooreresumespec/ > Patrick Moore > Alburquerque, Nouvelle Mexique, Vereinigte Staaten > > ************************************* > *The point which is the pivot of the norm is the motionless center of a > circumference on the rim of which all conditions, distinctions, and > individualities revolve. *Chuang Tzu > > *Kinei hos eromenon. It moves as the being-loved. *Aristotle > > *The Love that moves the Sun and all the other stars. *Dante > -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To unsubscribe from this group and stop receiving emails from it, send an email to rbw-owners-bunch+unsubscr...@googlegroups.com. To post to this group, send email to rbw-owners-bunch@googlegroups.com. Visit this group at http://groups.google.com/group/rbw-owners-bunch. For more options, visit https://groups.google.com/d/optout.
