Interestingly the bike repair bible that most of the experts defer to, i.e. 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.
Alan Turing using math to repair his bike
41–50 of 69 posts
Re: Alan Turing using math to repair his bike
#42Earlier quoted context omitted.
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.
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.
They were common, but you wouldn't have seen folks wearing them around the countryside, certainly not on a bike!
Re: Alan Turing using math to repair his bike
#43I think I read about this incident in the book "Cryptonomicon" by Neal Stephenson. It's pure fiction, mind you...
Re: Alan Turing using math to repair his bike
#44This 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
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.
Reamde is the only book of his I couldn’t get through.
Re: Alan Turing using math to repair his bike
#45Interestingly the bike repair bible that most of the experts defer to, i.e. 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.
(The web page hasn't been updated much for a while because Sheldon died several years ago.)
Re: Alan Turing using math to repair his bike
#46Earlier quoted context omitted.
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.
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 :).
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
Re: Alan Turing using math to repair his bike
#47Interestingly the bike repair bible that most of the experts defer to, i.e. 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.
(The web page hasn't been updated much for a while because Sheldon died several years 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/
Re: Alan Turing using math to repair his bike
#48Earlier quoted context omitted.
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'…
> then there's no downside to making the number of links prime if you can arrange it. Bike chains always have to have an even number of links because they come in inner and outer pairs. But this has an effect on chainrings as well. When the tooth on a chainring or sprocket is in between two inner plates it's in a narrow gap. When the tooth is in between outer plates that's a wide gap. If you have a chainring with an…
Just to add on:
Track chainrings don't need a narrow-wide profile because there's very little slack in the system for the chain to come off. Saint Sheldon warns of the possibility of losing a finger also for this reason.
Re: Alan Turing using math to repair his bike
#49No post body was provided.
Re: Alan Turing using math to repair his bike
#50Earlier quoted context omitted.
"I suppose this only applies to single sprocket bike."
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'…
Yeah, chains and cassettes are considered wear items, so I doubt manufacturers put much thought into patterned wear. Avoiding chain drop and crisp shifting are higher priorities.