The Smell of Molten Projects in the Morning

Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.

Category: Recumbent Bicycling

Cruisin’ the streets

  • AA Cell Dimensions

    Ever wonder why rechargeable AA cells don’t quite fit in older flashlights & gizmos? Somewhat to my surprise, the dimension specs for alkaline and rechargeable cells aren’t quite the same.

    At the bottom of the Wikipedia AA battery page, we find “brand-neutral” drawings (allegedly) based on ANSI specs:

    • Alkaline: 14.0 ± 0.5 dia x 49.85 ± 0.65
    • Rechargeable: 14.1 ± 0.6 dia x 48.9 ± 1.6

    A rechargeable cell can thus be 0.2 mm larger in diameter, but should have the same maximum length.

    Based on my collection, alkalines seem to be near their nominal and NiMH cells near their maximum. Across a four-cell layer, the difference adds up to 1 mm or so, which is enough to strain the plastic.

    8-cell NiMH AA pack
    8-cell NiMH AA pack

    Hint: Put some paper on the negative terminal when you measure the cell length. Steel calipers are pretty good conductors and the short-circuit ratings (even for alkalines) are surprisingly high  …

    When I make up NiMH packs for our bike radios, I lash the cells in place with cable ties. It’s not pretty, but the plastic cases don’t split.

    Connector? Anderson Powerpoles FTW! Make sure you align them properly to mate with anybody’s radio.

  • Park MTB-7 Rescue Tool Repair

    Too-short Stud
    Too-short Stud
    Goobered Screw Threads
    Goobered Screw Threads

    Once upon a time I deployed the 6 mm hex wrench on my trusty Park MTB-7 Rescue Tool, applied some torque to a handebar stem bolt, and crunch something broke inside the tool.

    [Update: Fixed a dead link; Park evidently reshuffled their website.]

    The essential problem is that the studs holding the tools in place are too short: they don’t seat fully into the plastic housing at the far end, because they’re 2 mm too short. The photo showing the stud at an angle gives an idea of the situation I saw when I took the tool apart.

    The crunching sound I heard was the screw tearing out as the stud shifted in the housing. The studs seem to be swaged into shape in one operation, but without quite enough material: the threaded end isn’t flat and the internal threads are crap. The photo showing the studs and screws can’t really show how off-center and feeble the internal threads really are, but you can see the junk lodged in the external screw’s threads where it tore out. Note the poor fit between the other stud’s end and its screw: it’s firmly seated against the stud, so that’s how far off square the end is!

    Better Screw and Sleeve
    Better Screw and Sleeve

    The fix was easy enough. I cut some brass tubing to the proper length, trimmed stainless-steel 10-32 screws to fit, and put everything together with red Loctite. The photo showing the all the parts indicates how much longer my sleeves are than the original studs: basically, that’s the thickness of the plastic housing on one side.

    But, sheesh, you’d expect a Park tool to be better than that. I sent ’em a note with pictures and maybe they’ll smack the factor who shorted ’em on the Quality bullet item upside the head.

    I got to spend some time playing with my toys, so it wasn’t a dead loss.

  • Spoke Wrenching

    I recently rebuilt the back wheel on my bike, which had been breaking the odd spoke and getting more & more out of true.

    Spoke wrenches are so tedious when one’s fingers don’t fit in between the spokes like they should. I figured, hey, if the pros can use power drivers, so can I…

    Dug a goobered #2 Philips bit out of the ziplock baggie labeled “NFG Bits” and applied it to the bench grinder. The strip of tape on one flat makes turn-counting easy enough that I can actually get it right. It’s not hardened, so it probably won’t last for more than a few wheels, but this is the first scratch-built wheel I’ve done in decades and that baggie is nowhere near empty.

    Homebrew Spoke Wrench Bit
    Homebrew Spoke Wrench Bit

    I read through Jobst Brandt’s The Bicycle Wheel to get prepped for the job, removed the old spokes, laced up the new ones, lubed the threads & rim washers, and the wheel trued up almost perfectly just by counting turns.

    Did the spoke aligning & stress-relieving tricks, applied some final tweaking, and it’s perfect!

  • Bicycle Performance

    Back in 2006 I biked to the Main Event Criterium in Po-town to watch real bicycle crazies in action. Despite the name, the course was literally around the blocks near the Poughkeepsie High & Middle Schools on Forbus St & College Ave: about 0.75 miles per lap.

    Now, most places, folks give ‘bent riders a smile and maybe chat ’em up. Not here. Talk about a cold shoulder: the local-resident bystanders were friendly, but the real riders and their main squeezes obviously regarded my pimped-out recumbent as a Hostile Gesture. Barely even a sideways look; it’s as if I didn’t exist.

    I timed a few laps of the Masters 40/50+ race: Olde Fartes like me, but still players. They did 15 laps (maybe a dozen miles) at 16-17 mph. Two guys duked it out for the lead all the way to the finish, with the rest of the pack half a lap behind and fading.

    In my ordinary rides I can cover a dozen or so miles at 15-16 mph, riding with vigor but not an all-out, my-eyeballs-will-explode effort. That’s on open roads with actual hills, traffic signals, and no pace car to clear the way.

    Obviously, I’m nowhere near their well-chiseled physical condition.

    There’s no comparing the bikes, either.

    They’re riding the latest carbon-fiber weight-weenie frames on exotic aero wheels with pitifully few spokes. One guy blew a tire with a bang that sounded like a gunshot.

    I’m riding a steel-frame Tour Easy recumbent bicycle with a fairing, fat Kevlar-belted tires, tire liners, steel spokes (and lots of ’em), a rack, two baggage packs, a water bladder, ham radio, blinky lights, spare batteries, a tool kit, and fenders. Not to mention an aerobelly. Heck, my tool kit probably weighs more than their frame.

    Imagine what they could do on real bikes…

    Somebody mentioned that the TdF guys hit 70+ mph on downhills. I forebore to mention that the human-powered speed record is nearly 80 mph on the flats… I figured that would definitely be regarded as a Hostile Gesture.

    [Update: a friend accused me of riding while carrying more smug than legally permitted, even for Prius drivers. Guilty as charged.

    You’ll find more ‘bent posts by clicking on the “Recumbent Bicycling” category.]

  • Christmas Day Ride

    Couldn’t pass it up: a family bike ride on Christmas Day in midstate New York!

    A mere 40 F and breezy, but no snow on the roads… a good time was had by all.

    Memo to self: fleece + bandanna is fine at 40 F.