Archive for category Recumbent Bicycling
We rode the Feeder Canal trail during a recent bike vacation in exotic Glens Falls NY:
The numerous downed branches along the trail and countless twigs on the trail came from a brush-clearing operation:
As luck would have it, a twig snagged between my front tire and fender, snapping the clips holding the fender in place:
Should it not be obvious, each ferrule formerly had two parallel jaws (on the left) gripping the fender, with the tiny screw digging into the fender. I affixed the fender to the broken clips with copious amounts of duct tape and we continued the mission.
It should be obvious why those ferrules are not suitable for 3D printing.
However, with the recent rear fender clip serving as inspiration, this didn’t take long:
The front fender fits a 20 inch wheel and is somewhat wider and flatter than the rear fender (I think they bent the same plastic strip around a smaller mandrel), so I did a quick copy-and-paste hack job on the OpenSCAD source code, rather than trying to parameterize the daylights out of the previous model.
The posts around the wire stays are 6 diameters deep and reamed to fit; the stays won’t be flopping around even without fiddly mechanical hardware retaining them. The holes extend about halfway into those posts to mimic the dimensions of the original ferrules.
All of us can predict where the next break will occur, right? That’s OK: I want this to break, instead of wrecking the fender, so the only question is how much abuse those simple joints can withstand. The printing orientation wraps the perimeter threads from the posts around the clip, making it about a strong as it can be.
The ferrules should splay outward by a few degrees to match the angle from the fender to the fork eyelets, but that’s in the nature of fine tuning.
The arch accommodates a strip of double-sided foam tape holding the clip in place along the fender curve, with those cute little hooks capturing the fender to keep the tape in compression:
I really must get some black foam tape …
The picture shows the fender sitting well away from the tire, due to the upper fender mount bending in response to the splash flap snagging on curbs and random debris; the wire stays didn’t seat completely into the posts.
The extender I made during the cracked fork episode remained perfectly straight, though:
So I re-bent the upper fender mount (not the extender!) to its original angle, thereby moving the bottom of the fender much closer to the tire. Now the stays seat fully, the clip holds the fender firmly in place with no rattles, and it’s all good.
The OpenSCAD source code as a GitHub Gist:
I’m towing a trailer of groceries southbound on Rt 376 (a.k.a. Hooker Avenue in this section), intending to turn right onto Zack’s Way for a library stop.
T=0.00 s, car @ 26.4 mph, me @ 19.8 mph
The transverse cracks through the asphalt are a convenient 60 ft apart, with the last one 20 ft from the stop line, and the frame numbers tick along at 60 frame/sec, so you can easily compute distances, times, and speeds.
I’ll be turning right at the intersection. The light is green.
T= 2.07 s, car @ 26.7 mph, me @ 19.7 mph
Now I can see the car’s right turn signal, so this might not end well. I can’t jam on the brakes and avoid a collision by dumping the bike at speed; I’ll slide under the car in the middle of the turn.
T=4.15 s, 15.2 mph
I’m 20 feet from the stop line and, suddenly, the driver also realizes this might not end well.
What he doesn’t know is that my trajectory must use the traffic lane: the shoulder around the corner is deteriorated, with several potholes, and vanishes completely where the intersection paving ends.
The driver is turning wide, into the opposing traffic lane, but if I weren’t lining up for the turn, we’d be on a collision course. My line will take me just to the left of the seemingly tiny, but very deep, pothole just ahead.
Leaning hard into the turn, but our paths won’t cross.
I’m back upright in the middle of the lane, with the shoulder ending in a pothole to my right.
Remember, I’m wearing a fluorescent (“safety”) orange shirt, running a blinky light (which is also the rear camera), and towing a trailer with a fluttering flag: I am not inconspicuous!
In case there’s any question:
The rest of the ride proceeded without incident …
The blinky light on Mary’s bike became intermittent and, after a week or two, I figured out why:
The white plastic case has a thin section labeled PUSH over the switch. After five years of exposure to the sun (it faces upward on her bike) and upwards of 2000 pushes (5 years x 200 rides/year x 2 pushes/ride), the edges of that little plate cracked, it slipped inward, and jammed the switch button.
I swapped it for the one on my bike, which mounts with the switch downward and has seen much less use since I began running the Fly 6 rear camera + blinky light, and it was all good.
The fractured plate slid snugly back in place, a few drops of IPS 3 solvent-bonded the broken edges, and a snippet of good 3M electrical tape inside the case should provide a bit of reinforcement:
It’s now on my bike, just in case it’s needed.
That was easy …
The first pleasant day after a long string of snow and rain got us outside again:
The honeybee at Mary’s elbow escorted us for a bit, then flew between us and continued on her mission.
Despite appearances, she passed a few inches from my helmet:
We all agreed: it was a fine day for a ride and a flight!
One of the clips holding the rear fender on my Tour Easy broke:
Well, if the truth be told, the fender jammed against the tire when I jackknifed the trailer while backing into a parking spot, dragged counterclockwise with the tire, and wiped that little tab right off the block. After 16 years of service, it doesn’t owe me a thing.
Although the clip around the fender sits a bit lower than it used to (actually, the entire fender sits a bit lower than it should be), you can see the tab had a distinct bend at the edge of the aluminum block supporting the underseat bag frame: the block isn’t perpendicular to the tire / fender at that point.
After devoting far too long to thinking about how to angle the tab relative to the clip, I realized that I live in the future and can just angle the clip relative to the tab. Soooo, the solid model has a rakish tilt:
The original design had a pair of strain relief struts where the tab meets the clip, but I figured I’ll add those after the PETG fractures.
I mooched the small bumpouts along the arc from the original design; they provide a bit of stretch & bend so to ease the hooks around the fender.
The hooks meet the clip with very slight discontinuities that, I think, come from slight differences between the 2D
offset() operation and the
circle() diameter; the usual
1/cos(180/numsides) trick was unavailing, so I tinkered until the answer came out right.
Despite those stretchy bumps, it took three iterations, varying the chord height by about 1.5 mm, to securely snap those hooks onto the fender:
Yeah, sorry ’bout the fuzzy focus on the screw head.
It’s impossible to measure the chord height accurately enough in that position and I was not going to dismount the rear tire just to get a better measurement.
You can see how the clip’s rakish tilt matches the fender’s slope, so the tab isn’t bent at all. It’ll probably break at the block the next time I jackknife the trailer, of course.
I heroically resisted the urge to run off a lower fender mount.
The OpenSCAD source code as a GitHub Gist:
The original doodle, with some measurements unable to withstand the test of time:
This big branch must have landed with a mighty thump across the Maloney Road entrance to the Dutchess Rail Trail:
Yeah, some jerk ran a snowmobile up the slope around the tree, leaving a pile of dirt on the ramp. So it goes.
We took an alternate route, I emailed The Right Folks, and (most of) the tree vanished two days later; evidently, the property owner gets to deal with everything to the left of the line of trees.
These guys looked completely disgusted with the situation:
They’re about 130 feet away in a heavy snowstorm that eventually deposited about a foot of wet snow on the area.
The top rail really does slant downward: the tenon on the right end broke and fell out of the mortise.
The DSC-H5 carries the 1.7× teleadapter, zoomed all the way tight through two layers of 1955-ish window glass, hand-held, braced against the pane.
The day before that snowstorm, we biked 18 miles out-and-back over the Walkway in beautiful, sunny, mid-50s (°F) weather:
We ride when we can and shovel when we must!