33 ms·

Alan Turing using math to repair his bike

112 points by johndcook 4y ago

avg_dev 4y ago
> And in Turing’s case, it was further complicated by the fact that he always wore a gas mask as he rode, to prevent triggering his allergies. But the alarm clock he was known to wear around his waist might have helped. What? Is that for real? Edit: It is! > He loved to ride his bicycle through the countryside. To time himself, he would simply tie an alarm clock around his waist. During the war, according to I.J. Good, a Cambridge mathematician, Turing suffered horribly from hay fever during the first week of June every year. So to keep the pollen off while riding, he wore a military gas mask. - https://www.washingtonpost.com/archive/1999/06/09/alan-turing/3640bb61-b23d-41df-9f39-d00a6b2e30cc/ https://www.washingtonpost.com/archive/1999/06/09/alan-turin...
- dTal 4y ago
  I wonder which part of this (admittedly odd fashion statement) seemed surprising to you? Gas masks were of course ubiquitous during the war, so this was probably only about as eccentric as wearing an N95 mask would seem now. And the alarm clock seems like a fairly practical if whimsical hack in an age when chronometers would have been mechanical, and therefore quite expensive.
  - avg_dev 4y ago
    I didn't know about the gas masks being ubiquitous during the war; that makes that part a little less surprising. History can be sad.
    - ihaveajob 4y ago
      I bought one at a swap meet in Amsterdam a few years ago. They were piled up high and cheap. It made a fun gift for a friend back home, but we got really odd looks on the train when wearing it :).
      - thenthenthen 4y ago
        Try Wear a N96 or FFP or surgical mask now in the train in NL and people will look at you in the same fashion haha
      - gmac 4y ago
        Ah, careful: https://www.nationalasbestos.co.uk/news/wwii-gas-masks-a-life-saver-or-a-potential-killer/ https://www.nationalasbestos.co.uk/news/wwii-gas-masks-a-lif...
    - switchbak 4y ago
      They were common, but you wouldn't have seen folks wearing them around the countryside, certainly not on a bike!
  - ravi-delia 4y ago
    I feel like the average person absolutely was not wearing a gas mask at all times. Having myself used an N95 in my neverending war on pollen I totally understand though.
    - dTal 4y ago
      No, of course people didn't routinely wear them. But every citizen was issued one. Children took them to school every day, and were drilled in their use. It's still an eccentric thing to do, of course. But, like the alarm clock tied around his waist, it was an instance of solving a problem by grabbing something close to hand.
- natly 4y ago
  Wasn't he a long distance runner. I wonder if he wore it then too.
- donthellbanme 4y ago
  For years before Covid, I would wear a N95 mask while doing yard work, construction, biking, and even night walks. I got some stares. For awhile, I felt some of my neighbors thought I was trying to conceal my identity; but it was just for allergies. The last thing I wore it for was germs.
  - CrazyStat 4y ago
    I've tried wearing an N95 for allergies, but my eyes still itch like mad so it's only moderately helpful.
    - ravi-delia 4y ago
      I thought about commenting you could wear goggles, but that's just reinventing the gas mask. Turing was a genius!
- deleted 4y ago
  [deleted]
matthewmcg 4y ago
This anecdote is memorably presented as an application of modular arithmetic (along with the behavior of Enigma machine rotors) in Neal Stephenson’s Cryptonomicon. See the discussion in this review of the book: https://www.ams.org/notices/199911/rev-kasman.pdf https://www.ams.org/notices/199911/rev-kasman.pdf
- lelandfe 4y ago
  I have a love/hate relationship with his writing – he adores going off on tangents, and action often gets put on pause while he savors them (REAMDE has several long paragraphs of a character pulling themselves onto a boat, admiring the hull, praising the usefulness of the tires lashed to it, etc). But it also introduces me to so many lovely things in the process. That moment in Cryptonomicon was quite cool.
  - ravi-delia 4y ago
    It's funny, I almost feel the opposite. I love the little weird tangents, but something about the expository bits never squared with me. Not sure why
  - idontwantthis 4y ago
    Reamde is the only book of his I couldn’t get through.
- phaedrus 4y ago
  Your mention of modular arithmetic makes me draw a connection between this story and the way I think about ceiling fan pull chains. Suppose the fan is clearly starting on high and you want to turn it off, but you don't know if the order of settings is "high-low-off", or "high-medium-low-off" (three states or four). It's often difficult to tell if the fan is coasting off or just spinning down to low. If you get it wrong and pull one time too many, it goes back to high and you have to start over. Therefore I always pull fan chains eleven (11) times to turn them off, so that I don't have to know if it's a three or four state fan. (Also works for on-off pull chains.) Pulling the chain 59 times would extend this technique to cover five-state fans, but I've never encountered one.
deleted 4y ago
[deleted]
sshlocalhost98 4y ago
Thanks for the fun story. I began appreciating mathematics and sincerely loving it due to the biographies of mathematicians like Sir Isaac Newton in Veritasium channel.
- onos 4y ago
  I enjoyed the story too. I noticed in another on the blog a mention of a book of selections from the blog, and plan to buy a copy. https://www.amazon.com/Math-Mutation-Classics-Interesting-Mathematics/dp/1484218914 https://www.amazon.com/Math-Mutation-Classics-Interesting-Ma...
BeniBoy 4y ago
Kind of reminded me of the traditional wisdom that you should select chains and sprocket to avoid patterned wear. I don't know if there is an effect (especially with bikes and their low torque),but I always think about it when changing my chain. I suppose this only applies to single sprocket bike.
- fyhn 4y ago
  Isn't this only relevant for fixed gear bikes, where you can skid the rear wheel to brake, and you want maximize the number of possible "skid patches", or orientations of the rear wheel while the pedals are in a fixed position?
  - analog31 4y ago
    It could also apply to the wear on the chainring and cog if their teeth are in a perfect proportion to one another, but without thinking too hard about it, I'm guessing that's actually rare. For instance a 2:1 ratio would be awkward for most cyclists riding on pavement (too low) and 3:1 too high, if they had to choose exactly one ratio. I ride 46:19, because those are the parts that were in my bin when I built the bike, and it's a pretty good all-round ratio for city riding unless you're a lot more athletic than I am. Also, those components wear out soon enough anyway -- a chain lasts 2 to 3 thousand miles, and a cog lasts a few chains.
  - namdnay 4y ago
    "I suppose this only applies to single sprocket bike."
    - jstanley 4y ago
      It applies to any bike. Ideally the number of links in the chain would be coprime to the number of teeth on every sprocket. The easiest way to achieve this is to make the number of links in the chain prime. It'll still work just fine if you ignore this idea, but it might wear out more quickly. If you're a hobbyist just trying to make something work, you can safely ignore it and do whatever is most convenient. If you're a bicycle engineer trying to make things reliable and long-lasting, then there's no downside to making the number of links prime if you can arrange it. I don't know whether bike companies actually do choose prime-numbered chains, maybe they have other constraints that are more important.
deleted 4y ago
[deleted]
isaacfrond 4y ago
- jacquesm 4y ago
  I can't picture this in a way that it would work, can you explain please? How would it hold air?
  - moistofreason 4y ago
    It wouldn’t
  - chmod775 4y ago
    > GPT-3 continuation. It's AI-generated nonsense.
    - jacquesm 4y ago
      Oh... totally missed that link, wow, that's really bad. It pollutes HN with garbage.
bbno4 4y ago
He used maths*, Alan was British.
- deleted 4y ago
  [deleted]
rtkwe 4y ago
Huh I always assumed that story was made up when it appeared in Cryptonomicon by Neal Stephenson.
dav_Oz 4y ago
From occasionally repairing modern bicycles the way the chain is falling off "regularly" doesn't click with me: If one spoke is bent so much (more like a serious wheel wobble) that - at some point - it touches a "damaged" chain link; this is quite a spectacular failure. I have to assume back then those bicycles were built quite differently that something like that could happen in such a predicatble fashion. Or along the way some information was lost and something different added in that anectode. Curious to see other versions I have quickly traced back the ancetode to a Nature article "Are mathematician logical" (1987) by Ian Stewart[0]; the version/wording unfortunately here is quite the same. [0]https://doi.org/10.1038/325386a0 https://doi.org/10.1038/325386a0 (via paywall --> sci-hub)
- tokai 4y ago
  Bikes back then weren't much different. Some from that time are still around and are not technically anything special. I don't buy the story. It might be what he told himself, but what fixed it was just the maintenance in general. Probs moved the wheel and tightened the chain. In any case if the bump of a crocked wheel could throw his chain, it was waaaay to loose.
deleted 4y ago
[deleted]
donquichotte 4y ago
I guess if you have a hammer, everything looks like a nail, even if you are Alan Turing! Tangentially related, I have recently become aware of a sound similar to a bag of potato chips being crushed coming from the rear wheel of my mountain bike. Closer inspection showed that the rear wheel hub exhibited an unwanted additional degree of freedom with respect to the rest of the wheel. The hub was able to be moved slightly back and forth radially. "An excuse to get my hands dirty, and an easy fix", I thought foolishly -- it is only mechanics, after all, nothing that will not surrender immediately to the agile mind and nimble hands of a computer programmer! Fast forward 300$ in tools of and 4 weeks of attempts to fix this, which typically resulted in the purchase of a new specialized tool, and the bike runs again. I learned more than I had hoped about the vast number of very small metal balls that reside in a modern freewheel hub, and it was a good lecture in humility.
- dekhn 4y ago
  When I was a kid, I had a similar noise (and resistance to turning). I took apart my bike with whatever tools I had and at some point found the ball bearings. Took them out, wiped off "all the dirty grease" and put them back in and tightened it all up. Needless to say, it got worse. It was a good lesson, though- only take apart your spare bike, and bring the prod bike to a real mechanic until you know what you're doing.
- vcdimension 4y ago
  You could make some of the money back from those tools, and help others in a similar situation, by renting them out on https://fatllama.com https://fatllama.com (or some other sharing website/app such as https://olioex.com/ https://olioex.com/). Sharing & hiring saves money and environmental impact.
bordercases 4y ago
This reminds me of when I unstuck a drawer using thermodynamics. The drawer was getting locked after I pulled it out X or so inches, where Y is the full length the drawer can come out and X < Y. I thought, "this is an implicit restriction on the degrees of freedom the drawer should have". Then I thought, well, if this system has fewer degrees of freedom than it should have, then I need to add degrees of freedom to it so that it may come unstuck. How to add degrees of freedom? Well, I could attempt to add entropy to the system, so that becoming unstuck could asymptotically become a part of its configuration space, and it may come free! I shook the drawer vigorously. It came unstuck. Physics!
vcdimension 4y ago
Interestingly the bike repair bible that most of the experts defer to, i.e. https://www.sheldonbrown.com/ https://www.sheldonbrown.com/ is written by a man who claims he was strongly influenced by the writings of Bertrand Russell, and he is married to a mathematician and has two children who are both mathematicians. The webpage contains several simple maths formulas for calculating things such as gear ratios.
- loeg 4y ago
  (The web page hasn't been updated much for a while because Sheldon died several years ago.)
  - vcdimension 4y ago
    It's kept upto date by employees of the bike shop he worked for (Harris Cyclery), his widow, and his friend John Harris (a nationally recognized bicycle expert). The most recent post was about 3 weeks ago: https://sheldonbrown.com/blog/ https://sheldonbrown.com/blog/
    - geocrasher 4y ago
      I am absolutely delighted to see Sheldon Brown's website posted on HN! It is an incredible resource.
    - loeg 4y ago
      Yeah, that's why I qualified it with "much." Trying to provide some context for HN readers unfamiliar with Sheldon.
  - Anthony-G 4y ago
    This was the website that made me fall in love with the World Wide Web and the “old Internet”. In the mid to late nineties, I was big into biking and liked to do my own bike maintenance. I came across Sheldon’s wonderful site (probably via Alta Vista) some time after a friend brought me to an Internet café and introduced me to the web. I still have a folder with all the pages I printed out so I could read it at home. RIP: https://sheldonbrown.com/blog/2022/02/03/its-been-14-years-now/ https://sheldonbrown.com/blog/2022/02/03/its-been-14-years-n...
janandonly 4y ago
I think I read about this incident in the book "Cryptonomicon" by Neal Stephenson. It's pure fiction, mind you...
- dredmorbius 4y ago
  The book is fiction. The incidents mentioned in it ... may not be.
spinaltap 4y ago
crispyambulance 4y ago
That's a charming story. It reminds me of skid-patch calculations on fixed gear bikes. If you have ride a brakeless track bike and "stop" or slowdown the bike by skidding, there's certain gear ratios that you'll want to avoid. Basically, in skidding, you unweight the rear wheel by moving your body forward and lock the position of your cranks. The rear wheel will then skid and you can end up with a flat spot of wear on your tire (assuming your don't face-plant yourself when you do it wrong). The fewer the number of skid patches for your gear-ratio, the more rapid the wear-down on the tire will be. There's even a calculator for this... https://www.bikecalc.com/skid_patch_calculator https://www.bikecalc.com/skid_patch_calculator If you're over 35, please, just use brakes and keep the track bike on the track! (stupid dangerous examples of skidding https://www.youtube.com/watch?v=W9xQcMniV84 https://www.youtube.com/watch?v=W9xQcMniV84, don't do it).
- phiiiillll 4y ago
  That's funny, I'm 41 and planning on setting up my brakeless track bike for the road again this afternoon (changing the gearing to 42-17 and switching from drops to a wide riser bar). If it goes badly I'll think of your warning.
- zh3 4y ago
  Even if you don't do skiddy tricks (but do a lot of miles) knowing the arithmetic leads into all sorts of interesting thinking about prime numbers - and, indeed, figuring out optimum gears ratios for (personal perference for) particular gear inches. Added to which, to minimise chain wear how big can we go at the front without hitting the chainstays/still making kerb jumps plus we want the number of links in the chain to be relatively prime as well. Agreed re brakes, on a bike having a decent front brake is all that matters (irrespective of age)- if stopping quickly, the back wheel is generally waving about in the air anyway so whether its leg-braked or other makes no difference (except fixed riders will still be pedalling, force of habit and all that).
Decabytes 4y ago
I’m always amazed at the genius of people like Turing and their ability to apply it in almost any situation they find themselves in
helloworld11 4y ago
Cue inevitable Cryptonomicon mentions.... What an amazing book though. Stephenson's best.

112 points by johndcook 4y ago

> And in Turing’s case, it was further complicated by the fact that he always wore a gas mask as he rode, to prevent triggering his allergies. But the alarm clock he was known to wear around his waist might have helped. What? Is that for real? Edit: It is! > He loved to ride his bicycle through the countryside. To time himself, he would simply tie an alarm clock around his waist. During the war, according to I.J. Good, a Cambridge mathematician, Turing suffered horribly from hay fever during the first week of June every year. So to keep the pollen off while riding, he wore a military gas mask. - https://www.washingtonpost.com/archive/1999/06/09/alan-turing/3640bb61-b23d-41df-9f39-d00a6b2e30cc/ https://www.washingtonpost.com/archive/1999/06/09/alan-turin...

dTal 4y ago
I wonder which part of this (admittedly odd fashion statement) seemed surprising to you? Gas masks were of course ubiquitous during the war, so this was probably only about as eccentric as wearing an N95 mask would seem now. And the alarm clock seems like a fairly practical if whimsical hack in an age when chronometers would have been mechanical, and therefore quite expensive.
- avg_dev 4y ago
  I didn't know about the gas masks being ubiquitous during the war; that makes that part a little less surprising. History can be sad.
  - ihaveajob 4y ago
    I bought one at a swap meet in Amsterdam a few years ago. They were piled up high and cheap. It made a fun gift for a friend back home, but we got really odd looks on the train when wearing it :).
    - thenthenthen 4y ago
      Try Wear a N96 or FFP or surgical mask now in the train in NL and people will look at you in the same fashion haha
    - gmac 4y ago
      Ah, careful: https://www.nationalasbestos.co.uk/news/wwii-gas-masks-a-life-saver-or-a-potential-killer/ https://www.nationalasbestos.co.uk/news/wwii-gas-masks-a-lif...
  - switchbak 4y ago
    They were common, but you wouldn't have seen folks wearing them around the countryside, certainly not on a bike!
- ravi-delia 4y ago
  I feel like the average person absolutely was not wearing a gas mask at all times. Having myself used an N95 in my neverending war on pollen I totally understand though.
  - dTal 4y ago
    No, of course people didn't routinely wear them. But every citizen was issued one. Children took them to school every day, and were drilled in their use. It's still an eccentric thing to do, of course. But, like the alarm clock tied around his waist, it was an instance of solving a problem by grabbing something close to hand.
natly 4y ago
Wasn't he a long distance runner. I wonder if he wore it then too.
donthellbanme 4y ago
For years before Covid, I would wear a N95 mask while doing yard work, construction, biking, and even night walks. I got some stares. For awhile, I felt some of my neighbors thought I was trying to conceal my identity; but it was just for allergies. The last thing I wore it for was germs.
- CrazyStat 4y ago
  I've tried wearing an N95 for allergies, but my eyes still itch like mad so it's only moderately helpful.
  - ravi-delia 4y ago
    I thought about commenting you could wear goggles, but that's just reinventing the gas mask. Turing was a genius!
deleted 4y ago
[deleted]

matthewmcg 4y ago

This anecdote is memorably presented as an application of modular arithmetic (along with the behavior of Enigma machine rotors) in Neal Stephenson’s Cryptonomicon. See the discussion in this review of the book: https://www.ams.org/notices/199911/rev-kasman.pdf https://www.ams.org/notices/199911/rev-kasman.pdf

lelandfe 4y ago
I have a love/hate relationship with his writing – he adores going off on tangents, and action often gets put on pause while he savors them (REAMDE has several long paragraphs of a character pulling themselves onto a boat, admiring the hull, praising the usefulness of the tires lashed to it, etc). But it also introduces me to so many lovely things in the process. That moment in Cryptonomicon was quite cool.
- ravi-delia 4y ago
  It's funny, I almost feel the opposite. I love the little weird tangents, but something about the expository bits never squared with me. Not sure why
- idontwantthis 4y ago
  Reamde is the only book of his I couldn’t get through.
phaedrus 4y ago
Your mention of modular arithmetic makes me draw a connection between this story and the way I think about ceiling fan pull chains. Suppose the fan is clearly starting on high and you want to turn it off, but you don't know if the order of settings is "high-low-off", or "high-medium-low-off" (three states or four). It's often difficult to tell if the fan is coasting off or just spinning down to low. If you get it wrong and pull one time too many, it goes back to high and you have to start over. Therefore I always pull fan chains eleven (11) times to turn them off, so that I don't have to know if it's a three or four state fan. (Also works for on-off pull chains.) Pulling the chain 59 times would extend this technique to cover five-state fans, but I've never encountered one.

deleted 4y ago

[deleted]

sshlocalhost98 4y ago

Thanks for the fun story. I began appreciating mathematics and sincerely loving it due to the biographies of mathematicians like Sir Isaac Newton in Veritasium channel.

onos 4y ago
I enjoyed the story too. I noticed in another on the blog a mention of a book of selections from the blog, and plan to buy a copy. https://www.amazon.com/Math-Mutation-Classics-Interesting-Mathematics/dp/1484218914 https://www.amazon.com/Math-Mutation-Classics-Interesting-Ma...

BeniBoy 4y ago

Kind of reminded me of the traditional wisdom that you should select chains and sprocket to avoid patterned wear. I don't know if there is an effect (especially with bikes and their low torque),but I always think about it when changing my chain. I suppose this only applies to single sprocket bike.

fyhn 4y ago
Isn't this only relevant for fixed gear bikes, where you can skid the rear wheel to brake, and you want maximize the number of possible "skid patches", or orientations of the rear wheel while the pedals are in a fixed position?
- analog31 4y ago
  It could also apply to the wear on the chainring and cog if their teeth are in a perfect proportion to one another, but without thinking too hard about it, I'm guessing that's actually rare. For instance a 2:1 ratio would be awkward for most cyclists riding on pavement (too low) and 3:1 too high, if they had to choose exactly one ratio. I ride 46:19, because those are the parts that were in my bin when I built the bike, and it's a pretty good all-round ratio for city riding unless you're a lot more athletic than I am. Also, those components wear out soon enough anyway -- a chain lasts 2 to 3 thousand miles, and a cog lasts a few chains.
- namdnay 4y ago
  "I suppose this only applies to single sprocket bike."
  - jstanley 4y ago
    It applies to any bike. Ideally the number of links in the chain would be coprime to the number of teeth on every sprocket. The easiest way to achieve this is to make the number of links in the chain prime. It'll still work just fine if you ignore this idea, but it might wear out more quickly. If you're a hobbyist just trying to make something work, you can safely ignore it and do whatever is most convenient. If you're a bicycle engineer trying to make things reliable and long-lasting, then there's no downside to making the number of links prime if you can arrange it. I don't know whether bike companies actually do choose prime-numbered chains, maybe they have other constraints that are more important.

deleted 4y ago

[deleted]

isaacfrond 4y ago

jacquesm 4y ago
I can't picture this in a way that it would work, can you explain please? How would it hold air?
- moistofreason 4y ago
  It wouldn’t
- chmod775 4y ago
  > GPT-3 continuation. It's AI-generated nonsense.
  - jacquesm 4y ago
    Oh... totally missed that link, wow, that's really bad. It pollutes HN with garbage.

bbno4 4y ago

He used maths*, Alan was British.

deleted 4y ago
[deleted]

rtkwe 4y ago

Huh I always assumed that story was made up when it appeared in Cryptonomicon by Neal Stephenson.

dav_Oz 4y ago

From occasionally repairing modern bicycles the way the chain is falling off "regularly" doesn't click with me: If one spoke is bent so much (more like a serious wheel wobble) that - at some point - it touches a "damaged" chain link; this is quite a spectacular failure. I have to assume back then those bicycles were built quite differently that something like that could happen in such a predicatble fashion. Or along the way some information was lost and something different added in that anectode. Curious to see other versions I have quickly traced back the ancetode to a Nature article "Are mathematician logical" (1987) by Ian Stewart[0]; the version/wording unfortunately here is quite the same. [0]https://doi.org/10.1038/325386a0 https://doi.org/10.1038/325386a0 (via paywall --> sci-hub)

tokai 4y ago
Bikes back then weren't much different. Some from that time are still around and are not technically anything special. I don't buy the story. It might be what he told himself, but what fixed it was just the maintenance in general. Probs moved the wheel and tightened the chain. In any case if the bump of a crocked wheel could throw his chain, it was waaaay to loose.

deleted 4y ago

[deleted]

donquichotte 4y ago

I guess if you have a hammer, everything looks like a nail, even if you are Alan Turing! Tangentially related, I have recently become aware of a sound similar to a bag of potato chips being crushed coming from the rear wheel of my mountain bike. Closer inspection showed that the rear wheel hub exhibited an unwanted additional degree of freedom with respect to the rest of the wheel. The hub was able to be moved slightly back and forth radially. "An excuse to get my hands dirty, and an easy fix", I thought foolishly -- it is only mechanics, after all, nothing that will not surrender immediately to the agile mind and nimble hands of a computer programmer! Fast forward 300$ in tools of and 4 weeks of attempts to fix this, which typically resulted in the purchase of a new specialized tool, and the bike runs again. I learned more than I had hoped about the vast number of very small metal balls that reside in a modern freewheel hub, and it was a good lecture in humility.

dekhn 4y ago
When I was a kid, I had a similar noise (and resistance to turning). I took apart my bike with whatever tools I had and at some point found the ball bearings. Took them out, wiped off "all the dirty grease" and put them back in and tightened it all up. Needless to say, it got worse. It was a good lesson, though- only take apart your spare bike, and bring the prod bike to a real mechanic until you know what you're doing.
vcdimension 4y ago
You could make some of the money back from those tools, and help others in a similar situation, by renting them out on https://fatllama.com https://fatllama.com (or some other sharing website/app such as https://olioex.com/ https://olioex.com/). Sharing & hiring saves money and environmental impact.

bordercases 4y ago

This reminds me of when I unstuck a drawer using thermodynamics. The drawer was getting locked after I pulled it out X or so inches, where Y is the full length the drawer can come out and X < Y. I thought, "this is an implicit restriction on the degrees of freedom the drawer should have". Then I thought, well, if this system has fewer degrees of freedom than it should have, then I need to add degrees of freedom to it so that it may come unstuck. How to add degrees of freedom? Well, I could attempt to add entropy to the system, so that becoming unstuck could asymptotically become a part of its configuration space, and it may come free! I shook the drawer vigorously. It came unstuck. Physics!

vcdimension 4y ago

Interestingly the bike repair bible that most of the experts defer to, i.e. https://www.sheldonbrown.com/ https://www.sheldonbrown.com/ is written by a man who claims he was strongly influenced by the writings of Bertrand Russell, and he is married to a mathematician and has two children who are both mathematicians. The webpage contains several simple maths formulas for calculating things such as gear ratios.

loeg 4y ago
(The web page hasn't been updated much for a while because Sheldon died several years ago.)
- vcdimension 4y ago
  It's kept upto date by employees of the bike shop he worked for (Harris Cyclery), his widow, and his friend John Harris (a nationally recognized bicycle expert). The most recent post was about 3 weeks ago: https://sheldonbrown.com/blog/ https://sheldonbrown.com/blog/
  - geocrasher 4y ago
    I am absolutely delighted to see Sheldon Brown's website posted on HN! It is an incredible resource.
  - loeg 4y ago
    Yeah, that's why I qualified it with "much." Trying to provide some context for HN readers unfamiliar with Sheldon.
- Anthony-G 4y ago
  This was the website that made me fall in love with the World Wide Web and the “old Internet”. In the mid to late nineties, I was big into biking and liked to do my own bike maintenance. I came across Sheldon’s wonderful site (probably via Alta Vista) some time after a friend brought me to an Internet café and introduced me to the web. I still have a folder with all the pages I printed out so I could read it at home. RIP: https://sheldonbrown.com/blog/2022/02/03/its-been-14-years-now/ https://sheldonbrown.com/blog/2022/02/03/its-been-14-years-n...

janandonly 4y ago

I think I read about this incident in the book "Cryptonomicon" by Neal Stephenson. It's pure fiction, mind you...

dredmorbius 4y ago
The book is fiction. The incidents mentioned in it ... may not be.

spinaltap 4y ago

crispyambulance 4y ago

That's a charming story. It reminds me of skid-patch calculations on fixed gear bikes. If you have ride a brakeless track bike and "stop" or slowdown the bike by skidding, there's certain gear ratios that you'll want to avoid. Basically, in skidding, you unweight the rear wheel by moving your body forward and lock the position of your cranks. The rear wheel will then skid and you can end up with a flat spot of wear on your tire (assuming your don't face-plant yourself when you do it wrong). The fewer the number of skid patches for your gear-ratio, the more rapid the wear-down on the tire will be. There's even a calculator for this... https://www.bikecalc.com/skid_patch_calculator https://www.bikecalc.com/skid_patch_calculator If you're over 35, please, just use brakes and keep the track bike on the track! (stupid dangerous examples of skidding https://www.youtube.com/watch?v=W9xQcMniV84 https://www.youtube.com/watch?v=W9xQcMniV84, don't do it).

phiiiillll 4y ago
That's funny, I'm 41 and planning on setting up my brakeless track bike for the road again this afternoon (changing the gearing to 42-17 and switching from drops to a wide riser bar). If it goes badly I'll think of your warning.
zh3 4y ago
Even if you don't do skiddy tricks (but do a lot of miles) knowing the arithmetic leads into all sorts of interesting thinking about prime numbers - and, indeed, figuring out optimum gears ratios for (personal perference for) particular gear inches. Added to which, to minimise chain wear how big can we go at the front without hitting the chainstays/still making kerb jumps plus we want the number of links in the chain to be relatively prime as well. Agreed re brakes, on a bike having a decent front brake is all that matters (irrespective of age)- if stopping quickly, the back wheel is generally waving about in the air anyway so whether its leg-braked or other makes no difference (except fixed riders will still be pedalling, force of habit and all that).

Decabytes 4y ago

I’m always amazed at the genius of people like Turing and their ability to apply it in almost any situation they find themselves in

helloworld11 4y ago

Cue inevitable Cryptonomicon mentions.... What an amazing book though. Stephenson's best.