SF Cyclotouring

Ride reports and other ramblings from a San Francisco cyclist.


Let there be Light!

Dual Cree XR-E Bicycle Headlamp
Originally uploaded by jimgskoop.
After an extended pull last night, my dual Cree XR-E LED bike headlamp is finished! I haven't done any testing yet, but at this point I'm happy that the thing lights up! Last couple of things I need to do are seal up the aluminum housing (my joints aren't very precise and thus they're not tight) and glue the acrylic lens in place. More info here.


Nearly Finished!

After too many days of measuring, cutting, filing, cursing, drilling, gluing, and bleeding, my dual Cree XR-E bicycle headlamp is nearing completion! I am super-excited and can't wait to show it off -- here's a sneak peak at the aluminum light housing during construction. I'm using thick-wall 1-1/4" square aluminum tubing as the basis for the light head unit, following a design similar to this one. To finish things off, I need to glue the LEDs onto the housing, carefully aligning the collimator lenses in the process. I also need to do some soldering to complete the wiring, and then cram everything inside the housing. Sealing the transparent acrylic lens cover over the LEDs will be the final step. Stay tuned!

2007.04.22 - Paradise Valley Fixie Loop

Orange Bike, Orange Bridge
Originally uploaded by jimgskoop.
Cyclofiend and I teamed up in a fixed-gear frenzy to ride the Paradise Valley Loop. I hadn't ridden a fixed gear across the GGB in quite a while, but it all worked out and we had a great ride. I was able to keep up, and didn't have to walk any of the hills (barely). Even better, we bumped into Carlos at the Tiburon coffee stop, and he joined us for the ride back home. 45 miles or thereabouts.


Dreaming of mini machine tools!

Last night, I (finally!) started on the construction of my DIY LED bike headlamp, which requires precise, right-angle saw cuts into a length of square aluminum tubing. Having only a hacksaw, I flubbed this up fairly badly and I will either need to cut a new piece, or use lots of silicone caulk to make the housing waterproof. This incident made me wonder how the hobbyist (read: on a budget) can produce precise cuts in metal? I know that there are low-cost, simple mitre boxes used with back saws to make cuts in wood, but these are often plastic or aluminum and would get shredded by a hacksaw blade... I started poking around on the interweb to see what I could find, and of course I ended up reading some posts on the rec.crafts.metalworking group, which didn't lead to anything hand-tool related...but certainly did whet my appetite for machine tools!

As long as I can remember, I've been fascinated with metal-cutting machine tools. When I was about 4 or 5, I remember my dad taking an old dead lawnmower to Goodwill or somesuch, and when it wouldn't fit in the trunk of the family car due to the length of the handle, he muttered something about cutting it off. I was in disbelief -- "Daddy, you can't cut metal!" I remember saying. He whipped out the hacksaw and cut the handle off the mower. I was amazed.

Years later as a young teenager, I had an uncle who was a pipe-fitter at a manufacturing plant. Due to some downsizing or other restructuring by his employer (I don't remember), he had to train as a weldor so he could perform both the pipe-fitting and welding functions in his job. Whenever we visited, he'd let me "play" with his oxy-acetylene torch, teaching me how to cut up scrap metal so he could haul it off for recycling. He once fired up his stick-welding unit and helped me make a little project, letting me wear the huge, dark face mask and guiding the electric-arc torch as I held it -- I really couldn't see what I was doing!

As an older teenager, I built random projects during summer breaks from school. A friend and I successfully built a recumbent trike from random iron pipe and an old Free Spirit ten-speed; it was held together with only nuts and bolts, but it worked! The family power drill was the only power tool I had access to and it was seriously abused in both drilling, sanding, and grinding functions. Many hacksaw blades were sacrificed to that project, and we bent the pipe used for the frame tubing by wedging it in the "V" of a large old forked tree trunk and yanking it by hand.

Studying engineering in college, I spent as much time as possible in the student machine shop in the sub-basement of Benedum Hall at the University of Pittsburgh. I wanted to learn about the huge lathes and milling machines, which to me represented complete "DIY freedom" and the power to make nearly anything! Unfortunately, machining technology was not part of the curriculum at that school, so my time in that shop was strictly limited to working on only a few simple school projects.

I've always wanted my own machine shop. These days, I'm fascinated by bicycle framebuilders who manage to gather together several large machine tools in a basement or shed...but since I live in an apartment, I doubt I'll be able to do this myself anytime in the near future.

However, I've recently learned that there are such things as mini machine tools -- bench-top drill presses, lathes, mills, saws, etc. Though certainly not professional quality, these tools are small and light enough that they can be stored away on a shelf or in a cabinet and pulled out when needed. They're also fairly low-cost, so getting a couple of key pieces (e.g., saw and drill press) would only run $200-300 or so. There are also low-cost mini-machines that combine drilling/milling/turning functions in one unit!

I think a shop-setup like this would be ideal for making small parts for bicycle accessories and the like!


I Hate Chainsuck!

Several months ago, I was riding my Bontrager and got some random nasty chainsuck. I winced when it happened, and I cried later on when inspecting the aftermath. Woe is my powdercoat! It was bad enough that the middle 34-tooth chainring got kinda warped, so I replaced it with another new one I had on hand, better to be safe than sorry I figured.

I rode that bike again yesterday. I scored a cheap set of long-sought XTR M-900 cranks at the recent Trips for Kids warehouse sale and I was eager to try them out. I wanted those cranks to fix a nagging chainring clearance issue that the Bonty's had since I first built it up using some cheap no-name cranks sourced from Craigslist. The M900s went right on using an absurdly-short 107mm UN-71 BB and everything looked good with improved 'ring clearance, the proper chainline, and less-but-still-enough crankarm/chainstay clearance (low Q definitely!).

So I went on a ride and had a good time, except at one point the front shifting got weird: Downshifting under any sort of load just wasn't happening. I stopped at one point to have a look-see and discovered that the front derailleur on this bike (a top-pull XTR unit) has an adjustment screw for the take-up spring tension. During a strange moment of deja-vu where I could've sworn that I'd dreamt about just this incident a few weeks ago (?!?!?), I tweaked that a bit and it seemed to set things right again.

As I was riding home from the GGB through the Presidio, I got a minor bit of chainsuck. Fortunately the Bontrager-specific chainsuck plate on my bike did its job protecting the paint this time, but after I re-'ringed the chain I was still having problems. I limped home and then discovered that a single tooth on the middle ring was bent outward, which served to throw the chain off the ring whilst pedalling. A-ha and rats, that was a new chainring.

So, two bouts of chain suck in only 3 rides, and this last one with a new chainring and a just-cleaned/lubed chain. Not a good record.

I measured the chain's wear and it's near the end of its service life, so I'll probably replace it. I popped on over to Sheldon's bike-oracle to do some reading up on the subject, and he links over to Jonathan Levy's extensive chainsuck thesis, which now has me asking further questions...

First, Levy's info suggests that a new chain will only exacerbate the problem, and that a slightly worn chain may actually be a short-term solution for suckage. He also posits that "2-ring suck" (chainsuck that happens when downshifting on the front and the chain spans adjacent rings) may be caused by a weird happenstance between the tooth-arrangements of the two rings...and in this case various solutions include: using ramped/pinned/profiled 'rings (e.g., Shimano SG), changing the tooth-difference 'tween the two 'rings (e.g., instead of 24-34-46 use 24-36-46) as the chain may be happier moving between a larger jump between middle and granny, or even simply rotating one of the rings to re-orient the adjacent teeth. Finally, replacing the granny 'ring seems like a safe thing to do.

There may be some truth to this: my C'dale with 24-36-46 rings has only ever once gotten chainsuck. It also has profiled Shimano Superglide (SG) 'rings (7-speed era). My Bonty has 24-34-46 standard unshaped 'rings. However, I've been riding that bike with those same 'rings for years (and before that, those same rings on a different crank on a different frame) and only recently has this problem cropped up.



CWS: Cycling Withdrawal Syndrome

Aside from a quite nice China Camp MTB ride a few weeks ago, I haven't been on a bike in nearly a month. Cold turkey, just stopped. Wait, I just checked the calendar and it's actually only been a couple of weeks. But it feels like a month, at least...so there.

Lots of things got in the way and conspired to leech my riding time and energy...

Firstly, I just haven't felt much like riding. We had a couple of great warm weekends followed by a cold spell, and I just didn't feel like having to bundle up after riding in short sleeves for a change. I also haven't been feeling well, and that was probably just the excuse I used to avoid riding. Or something.

After more than a year of looking, the wife and I finally found a groovy condo in the Mission that we're gonna buy. We might be able to start moving in as soon as the end of this month...which means I've got to figure out what bike junk I can keep and where it'll all live at the new place. I'm losing the awesome dedicated bike-workshop room I currently have at my rented flat, but the new place has a (shared) garage and 3 bedrooms, one of which will become my new office/studio/bike-room, so I should be OK for work space. I have to figure out an attractive way to store 4 bikes in that room so that they're mostly out of the way. Of course the bedrooms are all wall-to-wall carpeting; time & money permitting, I want to rip out the carpet in my new office and replace it with some snap-together tiles so I don't have to worry about the occasional drip or tire dirt. At any rate, dealing with the condo purchase has sucked up a couple of weekends of real-estate open-house visits, property inspections, lots of document reading and signing, and other not-so-fun stuff. Staring massive amounts of debt in the face is a stress-inducing experience!

I took a Saturday off from riding and worked on a couple of bikes: My Bontrager got some new-to-me XTR cranks, and the Cannondale is all set to sell, after getting some new tires and a different saddle (I want to hang onto the one it wore before).

Work has also been crazy lately, requiring me to bring my laptop home in the evenings and stay up late working. I haven't yet sorted out how to carry the laptop on my bike so I haven't been bike commuting either. Even without the laptop, the late nights are killing my up-at-5:45am schedule which precludes my taking Caltrain to work.

My mother also recently suffered a stroke, and this past weekend we headed back east to visit her and get in some family time. That was a tough one...not as bad as I feared, but still tough to deal with. Fortunately her rehab center let us take her home for a day so we had a good time cooking supper and having a meal around the table like a normal family. Mom's dealing with a lot of challenges right now, but she certainly eats OK and that's great!

The interesting thing about all this downtime has been that, at first, I went through some sort of bizarre withdrawal as (I guess) my body readjusted to less exercise. I guess I was (and hopefully still am) addicted to cycling! I avoided riding because I was tired and stressed -- and not riding only made me more tired and more stressed, downright irritable and cranky actually! Things got better after the first week, and now I just feel like a complete slug. I'm starting to get the itch to ride again, especially now that the weather's warmer.

I'm going to have to start packing in earnest soon, and I also really need to sell off a good pile of excess bike stuff which will require a massive and painful sorting /photographing/listing effort, but hopefully I'll have time to get back to my regular riding schedule...