Monthly Science: Bicycling!

Mary finished out the National Bike Challenge with a rank of 3353 of 47 k riders, which, by my reckoning, is wonderfully good. She’s #1 in the Poughkeepsie area (admittedly, of only eight riders), with the second-place rider at 90% of her point score.

She did it by riding on her usual missions, along our usual routes, around the usual obstacles:

NYS Rt 376 at Westview Terrace
NYS Rt 376 at Westview Terrace

Her bike odometer recently rolled past 20 k miles; at least one battery change stole a pile o’ miles from her total, so the bike has accumulated more than that.

As the song goes, my gal is red hot… in the best way!

17 thoughts on “Monthly Science: Bicycling!

  1. That’s awesome, and a lot of miles. I can’t remember where I am in the nbc right now, but I do remember that I’m overdue for changing the chain.

    1. Mary just put up all her numbers: Bit By Bit.

      This winter I’ll replace the entire drivetrain on both bikes. The parts have been on the shelf long enough: it’s time!

      1. Years ago, I was riding a lot in all weather. Got to the point where I had to change out individual worn sprockets in the cluster from my favorite gears. Chains could be kept going fairly long with help of a chain cleaner and decent lube–WD-40 is a good cleaning solvent, but a proper chain lube is needed beyond that.

        I ended up building a few wheels, and found Phil Wood hubs to be wonderful. Jobst Brandt’s The Bicycle Wheel is a classic–knew him slightly through work.

        Oh yeah, if your chainring bearings aren’t a cassette, it’s worth changing them to that. Beyond that, I never had to swap anything on the front of the drivetrain, beyond switching to my favorite pedals (I used the Look system).

        1. Phil Wood hubs

          We never leave home without them!

          When we got the bikes, I tried to use the Phil Wood bottom brackets I had on the shelf, but the tapers weren’t quite far enough out on the drive side. So we ended up with another other (Shimano?) sealed-bearing BB that’s worked just as well. The bikes have old-school headsets that are long overdue for cleaning & greasing.

          Having replaced the chains (which are 2-1/3 standard chains long) occasionally over the last twenty-some-odd-thousand miles, suffice it to say that the chainrings and sprockets are badly, badly worn.

    2. Years ago while on vacation, I was riding by myself through a very rural area of central Maine. When I was sufficiently far enough from civilization my chain decided it would be a fine time to break a link. Not having chain tools with me, I did the only thing I could, turned around and started walking. As luck would have it, before I had the chance to ponder what kind of pickle I was in, a pickup came by and I stuck out my thumb. The woman driving the truck slammed on the brakes, we threw the bike in the back and before I knew it, pulled into town. I think that one incident used up the next five years of my allotment of good luck.

  2. Can’t directly reply because of the indent-limit, but wow I’ve never managed to get 20k out of sprockets. (Especially titanium ones.) I’m surprised they still work! When you do replace them I’d love to see a picture of a tooth cross-section from a sprocket and the small chainring.
    I’ve been reading a bit about chain lubricant viscosity. It turns out the really good stuff that survives rain can suck up 10 watts compared to very lightweight, short-lifetime oils. Things I never considered…

    1. As best as I can recall (my riding days were 20+ years ago), 10K miles on my favorite sprockets was really good, and some times, 5K was more like it. I don’t recall wearing out a chain ring, though I was pretty good about cleaning/lubricating my chain. Not sure what I used (“Repeat after me: ‘WD-40 is not a lubricant.'”), though now I’d consider the aerosol grease intended for motorcycle chains. WE-40 is a good cleaner, though I used some of Park’s cleaner for a while.

      I never cared about power losses–I was the guy who’d do centuries on a mountain bike refitted with road tires.(Specialized FatBoys FTW!) I did need the granny chainring, though–had some serious hills on my favorite routes. Gave the bike away a year ago. [Snif] Somewhere around Klamath Falls is a rather odd Rockhopper…

      1. “Repeat after me: ‘WD-40 is not a lubricant.’”

        Of course! Any damn fool knows it’s a cologne…

    2. a picture of a tooth cross-section

      We definitely have a winning example of the “everything wears together” principle: those teeth have a rakish shark-fin attitude. The chain on Mary’s bike has begun skipping when she does two-step shifts in the back, so I’ve called end-of-life.

      At this point, I’m emptying random cans of spray lube from the stash that Came With The House™ and the chain has a nice layer of road dust grinding compound…

      1. Yeah, particularly on the racing mountain bike, it doesn’t take too long for the chainring teeth to look like they came off the wingtip of the Nemesis NXT aircraft. Man, chains stick on those rings. I had to go to stainless steel small and mid.

        1. stainless steel small and mid

          I keep thinking a guy with a CNC milling machine could make his own chainrings, but … [sigh]

          That requires a CNC milling machine substantially larger than the Sherline. I once doodled a setup involving a big aluminum carrier atop the rotary table, but it still needed an outrigger for (at least) the big ring.

    1. Seeing as how she’s in charge of long-term memory around here, that’s that… [grin]

  3. Trapped again by the limited-reply-nesting!
    I’ve done a chainring. I do the chainring bolts first, and then index the ring, to fit within the Sherline’s work envelope. I did cheat: it was for a modern Shimano four-arm chainring, with a divisible-by-four number of teeth, so I could just rerun the same code four times. I’m in the midst of coding up something to do the same process right now, in fact. I have a PCB that’s 5.2″ x 6.5″ and I need a cutout the size of the board, with four ears to hold the holes in each corner. Well, I can cut out the central section, because that’s only 4.6″, and then index using the holes in the ears to cut out the two outriggers that would otherwise overrun.

    But what that doesn’t do, is give you shift ramps and custom radiusing to make them shift like modern systems rather than like circa-1980 systems. (and the teeth need to be chamfered a little too to help with shifting, which means a trip to the lathe.)

    Which is a shame, because a cogset machined of aluminum with 15% aluminum oxide would outlast a steel cogset at 1/3 the weight. But without some serious knowledge of shift ramp design, it would shift like 1982.

    1. limited-reply-nesting

      OK, that’s now the maximum possible ten levels. Use sparingly: replies will neck down to about one word per line…

      shift like 1982

      There’s any other way? [grin]

      With the seat behind the bottom bracket instead of above it, all the fancy shifting doodads are completely out of phase with pedal position. I suppose that’s just more motivation to carve my own chainrings, if only I could figure out what to carve. As you say, modern rings barely resemble stamped-steel rings from the Bad Old Days.

      In compensation, though, the ‘bents have such a loooong chainline that cross-shifting isn’t a problem.

      1. I may be wrong about this but my impression was that chainramps and pins were correlated primarily with each other ring-to-ring and only secondarily with the dead phases of the crank.
        With that said, imitating a late-80’s chainring pair might not be too horrible. It’d certainly be a fun project, although man it seems hard to justify the time spent, given the price of ‘rings.

        1. it seems hard to justify the time spent

          Aye, other than as a Learning Experience, it makes no sense. Even though there’s a lot of that going on around here, it’s been on the back burner for a long time. [grin]

Comments are closed.