5 ms·

How the Bicycle Wheel Carries its Load: Held Up by Downward Pull (1980)

44 points by ggreer 11y ago

czardoz 11y ago
I wish that article had a few more diagrams to explain the concept. Nice read though.
- bliker 11y ago
  Just recently I made a crude simulation to compare Radial and cross lacing for wheels. http://gfycat.com/ThreadbareEdibleCormorant http://gfycat.com/ThreadbareEdibleCormorant. I did it in response to this reddit post. https://www.reddit.com/r/bicycling/comments/3cxk4v/just_made_this_discovery_after_a_long_ride_to_the/ https://www.reddit.com/r/bicycling/comments/3cxk4v/just_made...
SixSigma 11y ago
I'm a qualified wheel builder. It's not that difficult, just takes up to a couple of hours per wheel. Of course, they are mostly laced by machine nowadays. Building your own is good fun, plus you can do specials with fancy lacing or unusual hubs (such as hub based dynamos)
- stinos 11y ago
  It's not that difficult, just takes up to a couple of hours per wheel Once you know how to do it properly that is. The key to that is mentioned in the article: applying tension while building the wheel. Lots of it, in my (borrowed) experience. The first couple of wheels I built was before I had internet access and I just copied the lacing pattern from an existing wheel, then tightened and trued the wheel. It were the worst wheels I ever had and impossible to keep true (though I was riding trials back then which does require more from wheels). Then one day I found http://sheldonbrown.com/wheelbuild.html http://sheldonbrown.com/wheelbuild.html and would basically put all sorts of tension on wheels while building them. Lean on them, hammer the spokes, pull them together, smash the wheel against the wall and so on. This, together whith experience gained from many iterations, yields wheels which do not make the slightest sound when ridden for the first time and stay true even under heavy circumstances (I ride street/dirt on a 24" bmx now). As another comment mentions: wheelbuilding is definitely some sort of an art.
  - SixSigma 11y ago
    I don't do any of those things. I just progressively and evenly tighten up the nipples and then true the wheel on the stand.
    - analog31 11y ago
      I wonder if some of those rituals have been rendered obsolete by improvements to the quality of components and materials. I've been building my own wheels, since I started messing around with internal-gear hubs before they became fashionable. Today I follow the method as you describe -- aim for consistent high tension first, and then true it up. The gradual improvement of my technique seems to manifest itself, not so much in the truth of the wheels, but in greatly reduced spoke breakage.
  - wiredfool 11y ago
    Sheldon Brown was Awesome. Wonderful guy, full of arcane knowledge of the corners of the bike world, mainly those corners associated with unfashionable, interesting, reliable stuff. And he was willing to share it with anyone who would listen.
    - SixSigma 11y ago
      And he died on my birthday :(
  - bch 11y ago
    Counter-position: I've built lots of wheels, and raced on them (off road -- Canada Cup, NORBA, World Cup) and I have built wheels loading them up w/ stress (standing on them) based on conversations w/ other people, trading stories, etc., but after reading Jobst Brandts "The Bicycle Wheel" I chalk up those practices more to "voodoo" than science. Mind that the spoke will twist when you're tightening the nipple. Tighten evenly. Tighten in small increments. Tighten tight. Then relieve the twist in the spokes. The "pings" and noises you hear from a wheel are the twisted spokes snapping back into a position they really want to be in. They're twisted because the builder didn't relieve that twist as a finishing touch on the build. I have a 26" Mavic 517 laced to a Paul Components WORD hub with Wheelsmith Competition 14/15g spokes that I raced from ~1995 - 2005, and I still have it. True as the day I built it, and not adjusted after the build. Edit: add spoke specs.
Animats 11y ago
Right. This is similar to how bolted connections work. Bolted connections must be tight enough that, when loaded with a force pulling the bolted connection apart, the bolted surfaces still have pressure pushing them together. Wikipedia has a good explanation of this.
- analog31 11y ago
  Yes, and bearings too. For a bearing that will work under heavy load, the balls have to be "pre loaded," meaning that they are actually deformed just a bit, so they don't lose contact with the bearing races. All of these things are examples of structures held together by springs.
maaaats 11y ago
I just finished my master's thesis on optimizing lacing patterns for bicycle wheels using evolutionary algorithms [1]. To do that, I had to thoroughly investigate how they work to be able to write a wheel simulator. It's quite fascinating the forces a spoked wheel can withstand, given its simplicity and weight. And damn, "truing" a wheel to make the wheel round, not wobble and have equal forces on the spokes is an art. Even done iteratively with small changes one often end up making some part of the wheel worse when fixing one part. [1]: http://master.matsemann.com/ http://master.matsemann.com/
- SixSigma 11y ago
  I notice you found the regular lacings. Did you explore more fancy designs such as Crow's feet?
  - maaaats 11y ago
    I tried with an unbiased representation, and then it found all kinds of stuff, mostly bad patterns. The ones in the video are the non-dominated solutions found, and no crow foot there. It did find it, or something similar, on many of the runs. But it was dominated by other solutions. Of course, this may be an artifact of my simulation.
    - nerd_stuff 11y ago
      What about the POWerwheel lacing pattern? Remove some of those retarding spokes for extreme power gains! It may have dominated the other solutions so hard your computer tossed it out as an outlier and was too ashamed to report the error. Riders of the POWerwheel lacing pattern go so fast it's usually impossible to discern the lacing pattern from the wreckage they leave behind. To compound the problem most POWerwheel accidents are covered up as "space" attacking us with "meteors". http://sheldonbrown.com/power-wheel.html http://sheldonbrown.com/power-wheel.html
      - deleted 11y ago
        [deleted]
wiredfool 11y ago
FWIW, if you're interested in this subject, the best reference is Jobst Brandt's "The Bicycle Wheel". It's been out for 30 years or so, but it's still the best reference. Past that, you might want to look at Timeshenko and Geere's "Theory of Elastic Stability", but you'd need a good university library for that one.

44 points by ggreer 11y ago

czardoz 11y ago

I wish that article had a few more diagrams to explain the concept. Nice read though.

bliker 11y ago
Just recently I made a crude simulation to compare Radial and cross lacing for wheels. http://gfycat.com/ThreadbareEdibleCormorant http://gfycat.com/ThreadbareEdibleCormorant. I did it in response to this reddit post. https://www.reddit.com/r/bicycling/comments/3cxk4v/just_made_this_discovery_after_a_long_ride_to_the/ https://www.reddit.com/r/bicycling/comments/3cxk4v/just_made...

SixSigma 11y ago

I'm a qualified wheel builder. It's not that difficult, just takes up to a couple of hours per wheel. Of course, they are mostly laced by machine nowadays. Building your own is good fun, plus you can do specials with fancy lacing or unusual hubs (such as hub based dynamos)

stinos 11y ago
It's not that difficult, just takes up to a couple of hours per wheel Once you know how to do it properly that is. The key to that is mentioned in the article: applying tension while building the wheel. Lots of it, in my (borrowed) experience. The first couple of wheels I built was before I had internet access and I just copied the lacing pattern from an existing wheel, then tightened and trued the wheel. It were the worst wheels I ever had and impossible to keep true (though I was riding trials back then which does require more from wheels). Then one day I found http://sheldonbrown.com/wheelbuild.html http://sheldonbrown.com/wheelbuild.html and would basically put all sorts of tension on wheels while building them. Lean on them, hammer the spokes, pull them together, smash the wheel against the wall and so on. This, together whith experience gained from many iterations, yields wheels which do not make the slightest sound when ridden for the first time and stay true even under heavy circumstances (I ride street/dirt on a 24" bmx now). As another comment mentions: wheelbuilding is definitely some sort of an art.
- SixSigma 11y ago
  I don't do any of those things. I just progressively and evenly tighten up the nipples and then true the wheel on the stand.
  - analog31 11y ago
    I wonder if some of those rituals have been rendered obsolete by improvements to the quality of components and materials. I've been building my own wheels, since I started messing around with internal-gear hubs before they became fashionable. Today I follow the method as you describe -- aim for consistent high tension first, and then true it up. The gradual improvement of my technique seems to manifest itself, not so much in the truth of the wheels, but in greatly reduced spoke breakage.
- wiredfool 11y ago
  Sheldon Brown was Awesome. Wonderful guy, full of arcane knowledge of the corners of the bike world, mainly those corners associated with unfashionable, interesting, reliable stuff. And he was willing to share it with anyone who would listen.
  - SixSigma 11y ago
    And he died on my birthday :(
- bch 11y ago
  Counter-position: I've built lots of wheels, and raced on them (off road -- Canada Cup, NORBA, World Cup) and I have built wheels loading them up w/ stress (standing on them) based on conversations w/ other people, trading stories, etc., but after reading Jobst Brandts "The Bicycle Wheel" I chalk up those practices more to "voodoo" than science. Mind that the spoke will twist when you're tightening the nipple. Tighten evenly. Tighten in small increments. Tighten tight. Then relieve the twist in the spokes. The "pings" and noises you hear from a wheel are the twisted spokes snapping back into a position they really want to be in. They're twisted because the builder didn't relieve that twist as a finishing touch on the build. I have a 26" Mavic 517 laced to a Paul Components WORD hub with Wheelsmith Competition 14/15g spokes that I raced from ~1995 - 2005, and I still have it. True as the day I built it, and not adjusted after the build. Edit: add spoke specs.

Animats 11y ago

Right. This is similar to how bolted connections work. Bolted connections must be tight enough that, when loaded with a force pulling the bolted connection apart, the bolted surfaces still have pressure pushing them together. Wikipedia has a good explanation of this.

analog31 11y ago
Yes, and bearings too. For a bearing that will work under heavy load, the balls have to be "pre loaded," meaning that they are actually deformed just a bit, so they don't lose contact with the bearing races. All of these things are examples of structures held together by springs.

maaaats 11y ago

I just finished my master's thesis on optimizing lacing patterns for bicycle wheels using evolutionary algorithms [1]. To do that, I had to thoroughly investigate how they work to be able to write a wheel simulator. It's quite fascinating the forces a spoked wheel can withstand, given its simplicity and weight. And damn, "truing" a wheel to make the wheel round, not wobble and have equal forces on the spokes is an art. Even done iteratively with small changes one often end up making some part of the wheel worse when fixing one part. [1]: http://master.matsemann.com/ http://master.matsemann.com/

SixSigma 11y ago
I notice you found the regular lacings. Did you explore more fancy designs such as Crow's feet?
- maaaats 11y ago
  I tried with an unbiased representation, and then it found all kinds of stuff, mostly bad patterns. The ones in the video are the non-dominated solutions found, and no crow foot there. It did find it, or something similar, on many of the runs. But it was dominated by other solutions. Of course, this may be an artifact of my simulation.
  - nerd_stuff 11y ago
    What about the POWerwheel lacing pattern? Remove some of those retarding spokes for extreme power gains! It may have dominated the other solutions so hard your computer tossed it out as an outlier and was too ashamed to report the error. Riders of the POWerwheel lacing pattern go so fast it's usually impossible to discern the lacing pattern from the wreckage they leave behind. To compound the problem most POWerwheel accidents are covered up as "space" attacking us with "meteors". http://sheldonbrown.com/power-wheel.html http://sheldonbrown.com/power-wheel.html
    - deleted 11y ago
      [deleted]

wiredfool 11y ago

FWIW, if you're interested in this subject, the best reference is Jobst Brandt's "The Bicycle Wheel". It's been out for 30 years or so, but it's still the best reference. Past that, you might want to look at Timeshenko and Geere's "Theory of Elastic Stability", but you'd need a good university library for that one.