I need to replace the mesh seat on my recumbent bicycle, because one of the buckles snapped yesterday. The mesh itself is badly stretched and abraded, and a few of the webbing straps are badly worn, so it is not worth repairing the seat—it’s replacement time. I can still ride the bike, but it isn’t as comfortable with the front strap no longer functional.
Now I’m trying to figure out exactly what fabric and parts to get. One person on the Ryan owner’s club mailing list conveniently provided a parts list recently, though the seat I have currently does not exactly match his list (for example, I have all 1″ webbing, no 3/4″ webbing). Here are some things I’m trying to decide:
- What type of mesh should I get? He recommended black Leno Lock mesh from Outdoor Wilderness Fabrics MESHBLK at $14.03/yard, but I’m also considering Phifertex Vinyl Mesh at $12.95/yard, which is available in many colors, or Phifertex Plus at $17.95/yard, which would provide less stretch, but also less ventilation. The Phifertex Plus is sold as a sling mesh (capable of supporting a person’s weight), but the others are not. I suspect that any fabric rated for seats will have too little ventilation for the recumbent. The leno weave fabrics are likely to provide more stability in an open mesh, because the warp threads twist around each other, rather than running straight, locking the weft threads in place. The bentrideronline forum posts generally recommend the Leno lock mesh from Outdoor Wilderness Fabrics, so I’ll probably go with that, even though it is a bit too stretchy.
- What sort of webbing should I get? The edges of the seat use 2″ webbing to stabilize the seat and attach the straps, plus a couple of diagonals from the center front to part way up the sides, to support the weight of the rider. The rest of the straps are 1″ wide. But should they be nylon, polypropylene, or polyester straps? Nylon has high strength, but is rather stretchy. Polypropylene has less stretch, but poor abrasion resistance and UV resistance, and polyester has the best UV resistance and the least stretch (about half as much as nylon webbing of the same weight under the same stress). It also doesn’t absorb water, and is more resistant to mildew and rot.
I can get black polyester 1″ webbing for about 35¢/foot, and 2″ black polyester webbing for about 75¢/foot, but colors are a little more expensive: I can get 10 yards of red 1″ with reflective stripes for $18.90, or plain red for $1.48/yard. For a bicycle application, the reflective stripes may be a useful safety feature. Red 2″ seatbelt webbing would be about $10 for 5 yards.
- I also need to get buckles for the 7 cross straps and the two straps that go over the top of the seat. I’m undecided between simple side-release buckles (Fastex FSR1 59¢), and dual-pull side release buckles (generic GTSRD1 47¢) from Outdoor Wilderness Fabrics. Cam lock buckles (generic GCB1 46¢) are also a possibility. I’ll also want a a tri-glide for each loose strap end (generic GTG1 12¢).
So, unless I can get a new seat from the manufacturer of my bike (Longbikes in Colorado), even though they discontinued this model about 10 years ago, I’ll probably be making my own seat soon. It’ll cost me about $50–60 for materials, but I suspect that an already sewn seat would cost more like $150, and I wouldn’t have the option of red straps with reflective stripes.
For years I’ve been collecting pictures of bike parking (good and bad), but I’ve not written about the racks much. Recently I came across three excellent reviews of bad bike racks on the One woman. Many Bicycles. blog:
Bike Rack FAIL: The Jaws of Death Torture Rack
Bike Rack FAIL: The Throat Choke Torture Rack
Bike Rack FAIL: The Ankle Biter Torture Rack
Go read her posts about these poor excuses for bike parking devices. Note: none of these work at all with my recumbent bike.
There is an even worse design out there—various versions of the wheel-bender:
Here is a wheel-bender that I photographed at MIT a few years ago. The main characteristic of a wheel bender is that it holds the bottom of the wheel without supporting the frame. This maximizes the leverage for bending the wheel if the bike is knocked over.
I see variants of these bike-damaging excuses for bike parking all over the place, but have not taken many pictures of them. The wheel benders are very cheap, can be squeezed into very little space, are visually unobtrusive, and are universally hated by bicyclists—those features make them popular with places that are required to put in bike parking but really want to discourage bicyclists—the nearest MacDonald’s has wheel-benders, for example. I do not patronize businesses that use them (unless forced to do so, and then I try to talk to the manager about their anti-bike design).
If readers of my blog are interested in seeing some of the bike parking pictures I’ve taken, let me know, and I’ll try to do posts of some of the more interesting ones. Mostly I’ve taken pictures of good (or at least adequate) bike parking, but I do have some photos of common design or installation errors.
After feeling a bit down yesterday about needing to reboot my teaching in the Applied Circuits course after the quiz, I went to bed early, as I needed to get up early this morning to judge a science fair at the K–8 school where my wife works. I managed to fall asleep, but woke up again before 3:00 a.m., with my mind still running around in circles trying to come up with ways to get the students to learn what I want them to learn in the circuits class. I’ve been getting insomnia a lot lately, and it is not at all helpful.
When reading some mindless fantasy novel did not help me shut down the monkey chatter and get back to sleep, I got up to catch up on e-mail and blog reading (mostly mindless stuff also, though I sometimes come across a good idea on the teacher blogs). Reading e-mail when I have insomnia is a bit dangerous, as it often results in my finding out about a missed deadline or some bureaucratic emergency I have to deal with, leading to more lack of sleep. Tonight there were no new disasters, and I managed to clean out a few old e-mails that could be handled with a short reply or simply filed and forgotten.
I spent a little time reflecting on my day, looking for positives to cheer myself up a bit. There were a few:
- I had gotten a draft started on the lab handout for next week (the FET and phototransistor lab), and gotten a number of schematics drawn for it. They always take me more time than they should, so getting them done put me back on schedule for this lab handout—I should be able to get it done in time to release by Thursday evening, despite having two mornings this week spent on science fair judging.
- My son had come up to campus early for his class, so that he could debug the data logger on the Windows machines. It has not been showing the menus the way it is supposed to, but the bug only occurs on Windows machines, so he couldn’t debug it at home (we’re a no-Windows household). He quickly tracked down the bug—it seems to be a bug in Tk, though not one we could find mention of on the web—he’ll be asking about it on StackOverflow. He has a workaround figured out for it, but the workaround requires some refactoring, as he had associated “quit” functionality with code for the system menu, and it is adding to the system menu that is causing Windows to suppress the menubar. Once he gets that problem fixed, he just has one Linux bug to track down and a little more documentation to do before he’s ready for his first official release. So I’m quite pleased with the progress he’s making on the data logger.
- On my way into work this morning, I saw bicyclist on the bike path staring disconsolately at his derailleur. I stopped to ask if he needed help, and he said that his chain kept slipping out of gear. I spent a minute asking diagnostic questions: just in the lowest gear? or in all gears? Both derailleurs or just the rear? When he said that it was in all gears and just the rear derailleur, I guessed that the problem was the cable adjustment, and looked for the barrel adjuster to adjust the cable housing length. There wasn’t one. At first this confused me—who would put a cable on a shifter without a length adjustment? Then I looked more closely at the rear derailleur and realized that it had a screwdriver-dependent adjuster, rather than a barrel adjuster. I’d not seen that on a bike before, but the bike looked like an old one (with shift levers on the downtube) and not particularly high quality, so it may have been a cheap design that did not survive in the marketplace. I got out the screwdriver on my Swiss Army knife and turned the adjusting screw a quarter of a turn to lengthen the housing. We checked the derailleur and it seemed to shift ok, so I suggested he take the bike to the Bike Co-op or the Bike Church to learn how to adjust the derailleur properly and continued up the hill. At the top I waited half a minute to ask him as he rode by whether it was shifting ok now, and he thought that it was. The total time added to my morning commute was about 3 minutes, and doing a good deed like that lifted my mood for a couple of hours.
- In my lab office hours after class today, one of the students who had been having a little trouble with the soldering last Thursday needed to redo the board. The one he’d been working on last Thursday had gotten solder in a couple of the holes before the components had been added, and we had delaminated one of the traces trying to clear the holes. I was able to borrow a soldering iron from another lab (they don’t want to leave soldering irons in the lab I use, because the students in the EE circuits class can’t be trusted not to burn themselves, I guess), and the student was able to unsolder the screw connector from the old board and solder up the new board without mishaps. I helped a bit with unsoldering the screw connector. I even had an opportunity to teach him the resistor color code, because he had forgotten what resistance value they had used (bad lab notebook keeping) and asked me if there was any way to read the markings on the resistor to determine its value. Luckily, the colors were unambiguous on the resistor he was using (some of the markings are unclear on the blue-bodied resistors), so we could read it easily as a 4.7MΩ resistor. I didn’t tell him the other approach, which is to measure the resistor with an ohmmeter, since that method is unreliable when the resistor is in a circuit—it is easy for other current paths through the circuit to make the ohmmeter read low (or high, in the case of a parallel capacitor). It’s probably a good thing I didn’t suggest that, as I just checked on my hysteresis oscillator board and an in-circuit measurement there is off by a factor of five. In any case, he managed to solder the new board up and demo it fairly quickly. I think that leaves just one or two students who still need to demo their working soldered boards.
So despite the setback of the quiz showing me that more pseudoteaching than teaching has been taking place this quarter, I did have several positive moments yesterday. I need to remind myself of the positives more often.
I’ll work for another half hour or so tonight (either on the lab handout or on some research code), then try to get back to sleep before getting up earlier than usual to do the science fair judging.
Last week, I reported on my son’s bike saddle and seatpost getting stolen and ditched in the bushes—behavior I had a hard time explaining.
Today, my son examined the recovered saddle and realized that it wasn’t his, but was a lower quality saddle. So now we have a potential explanation—the saddle was stolen by someone on a bicycle, who upgraded their saddle then ditched the old one. I hesitate to call the thief a bicyclist, though, since they did not even bother putting the crummy saddle on my son’s bike. A saddle swap would still have been a theft, but would have left my son’s bike usable.
I suspect that the thief was on a stolen bike and was trying to replace parts to make it look less recognizable.
Wednesday night, while my son was in theater class, his bike post and saddle were stolen, so he had to walk his bike home. On Thursday morning, we went to the nearest bike shop (Sprockets), and bought him a new seat post and saddle, a lock for the saddle, and new bracket for his rear light (which had been mounted on a bracket on the seat post). This cost about $70 and took us about an hour—not a crushing burden, but definitely a nuisance. Later in the day, we got a call from the theater staff: they had found his post and saddle in the bushes near the theater. He’ll get them back tomorrow and will have a spare. So we’ve spent $70 that was probably unnecessary (if we had the leisure for him to be without transportation for a day, which we don’t), and lost some time (walking the bike home and buying a new saddle). At least he now has a lock for his saddle, so it is unlikely to get stolen again.
I don’t understand the mentality of someone who would steal a seat post and saddle and then ditch it in the bushes nearby. That doesn’t benefit anyone. I can understand (and hate) the petty thefts done by meth heads to feed their habit, but I don’t understand a theft just to discard what was stolen. Was it someone who hated bicyclists and wanted to harass one? Someone so drug-damaged that they stole the saddle, then couldn’t remember why? I might have suspected a childish prank by one of his classmates (none of whom are cruel, but some of whom might be childish enough for such a prank), but they were all in the theater class at the time of the theft.