I fancy myself as a kind of bicycle godfather to my younger siblings. I try to make sure they each have working bicycles, and I try to pass on little tidbits of knowledge when I can. On the whole it's an enjoyable role to play, but sometimes it can be a little discouraging. Their bikes always seemed to brake down the minute I leave town. It's like there is some kind of bicycle sabateur troll waiting around to sabatoge the family bikes as soon as no one is looking.
I was at my parents house this weekend, for example, and everything was in disarray. My youngest brother had brand new bar tape that looked like it was 10,000 year old mummy wrap. --Pieces hanging off, then ends overlapped backwards and taped right up to the stem. His brake cables were somehow tangled into acute angles sharply under the handlebars. I couldn't figure that one out. It looked like somebody would have had to take the brake levers off and position the break cables at sharp angles deliberately.
My other brother had not only a puncture in his rear inner tube, but then three more pinch flats from when he had ridden the bike home without air in the tire. At that point it's still economical to patch the tube, it's just a little ridiculous. Of course it was Sunday, so there weren't any bike shops open to sell us a new tube. I patched it up and it held air, it just looks like it has some kind of rubber susceptible case of the patch-measles.
The coup de gras was when I was about to race my youngest brother (a race which he ended up winning, but that's another story,) and I looked down at his front wheel to see that he had tightened his quick release lever all the way down and not clamped it closed. Which is of course hilarious, but only because I saw it before he was able to do an endo.
Monday, November 3, 2008
Friday, October 17, 2008
The Ten Commandments and the Well Ordering Principle
When I was a kid (and all through my life, really,) my mother would periodically tell me to:
"remember the fourth commandment, the only commandment with a promise. --Honor your father and mother, that it will go well with you."
I was reminded of this last night while reading Sarah Vowell 'The Wordy Shipmates.' There is a part in this book where she's talking about how, for the puritans, this commandment applied not just literally to your parents but also to figures of authority (governments and such.) The only thing is that she calls it the fifth commandment.
So, excited at the chance to play scholar, I went to my bible and looked it up. And, sure enough, it was the fourth. So then I went and asked around the house, and somebody had another bible, and that one had it as the fourth too. The thing is, though, that nobody's bible enumerated the commandments. You have to count them yourself. --Since they are written in verse form, without numbers. And really, I wasn't sure if I was counting them right, because it seemed to me that there were really only nine commandments.
So this morning I looked it up on the internets. According to Wikipedia, there are several different traditions depending on your denomination. It just depends on how you split up the verses. Some people say that "you shall have no other gods before me," and "you shall not make yourself a false idol" are two different commandments. Whereas other people say that "you shall not covet your neighbors possessions" and "you shall not covet your neighbors wife" are two different commandments (when I had thought there only seemed like 9 commandments I was lumping both "don't covets" together as one commandment, and also lumping "don't make a false idol" and "have no other gods before me" as one commandment.)
The tradition of splitting up the "don't covets" but keeping the "don't make false idols" and "have no other gods before me" as a single commandment seems more reasonable to me but, honestly, it probably really doesn't matter a whole lot. This is the kind of thing that people probably got killed over in the 16th century. Hard core religious people would probably still get a little too worked up over it even today.
Anyway, all this thought about ordering reminded me of one of the first theorems that one learns in elementary number theory, The Well Ordering Principle. This theorem says that any collection of non-negative integers will always have a smallest integer. Think about this for a moment and you will see that what this theorem is really saying is that any collection of non-negative integers can be listed in order, or ranked (that's why it's called the Well-Ordering Principle.)
That theorem turns out to be an important building block in number theory, but what does it have to do with the Ten Commandments? I guess the point is that the numbering of the commandments matters only if it is also a ranking. i.e. commandment #1 is more important than commandment #2, commandment #5 is less important than commandment #4, etc.
I'm actually curious to know what religious traditions, if any, do consider the enumeration of the commandments to be a ranking. Maybe I'll give my dad a call and ask if he knows.
If she were ranking them, I'm pretty sure my mother, given here druthers, would have made "honor your father and mother" a little higher.
"remember the fourth commandment, the only commandment with a promise. --Honor your father and mother, that it will go well with you."
I was reminded of this last night while reading Sarah Vowell 'The Wordy Shipmates.' There is a part in this book where she's talking about how, for the puritans, this commandment applied not just literally to your parents but also to figures of authority (governments and such.) The only thing is that she calls it the fifth commandment.
So, excited at the chance to play scholar, I went to my bible and looked it up. And, sure enough, it was the fourth. So then I went and asked around the house, and somebody had another bible, and that one had it as the fourth too. The thing is, though, that nobody's bible enumerated the commandments. You have to count them yourself. --Since they are written in verse form, without numbers. And really, I wasn't sure if I was counting them right, because it seemed to me that there were really only nine commandments.
So this morning I looked it up on the internets. According to Wikipedia, there are several different traditions depending on your denomination. It just depends on how you split up the verses. Some people say that "you shall have no other gods before me," and "you shall not make yourself a false idol" are two different commandments. Whereas other people say that "you shall not covet your neighbors possessions" and "you shall not covet your neighbors wife" are two different commandments (when I had thought there only seemed like 9 commandments I was lumping both "don't covets" together as one commandment, and also lumping "don't make a false idol" and "have no other gods before me" as one commandment.)
The tradition of splitting up the "don't covets" but keeping the "don't make false idols" and "have no other gods before me" as a single commandment seems more reasonable to me but, honestly, it probably really doesn't matter a whole lot. This is the kind of thing that people probably got killed over in the 16th century. Hard core religious people would probably still get a little too worked up over it even today.
Anyway, all this thought about ordering reminded me of one of the first theorems that one learns in elementary number theory, The Well Ordering Principle. This theorem says that any collection of non-negative integers will always have a smallest integer. Think about this for a moment and you will see that what this theorem is really saying is that any collection of non-negative integers can be listed in order, or ranked (that's why it's called the Well-Ordering Principle.)
That theorem turns out to be an important building block in number theory, but what does it have to do with the Ten Commandments? I guess the point is that the numbering of the commandments matters only if it is also a ranking. i.e. commandment #1 is more important than commandment #2, commandment #5 is less important than commandment #4, etc.
I'm actually curious to know what religious traditions, if any, do consider the enumeration of the commandments to be a ranking. Maybe I'll give my dad a call and ask if he knows.
If she were ranking them, I'm pretty sure my mother, given here druthers, would have made "honor your father and mother" a little higher.
Thursday, October 16, 2008
laws of men, laws of physics: culture is learned
One of the things that worried me about coming back to Oregon after spending the summer in NY was whether or not I'd be able to break the habit of running red lights.
I've posted about this before --how Portland is a little uptight when it comes to such things. Here you will get called out by other cyclists, motorists, --lots of people feel it is their place to be your mother.
Whereas in NY the modus operandi of virtually every cyclist amounted to, to quote (I think) Lucas Brunelle, "there is no law but the laws of physics."
Anyway it hasn't been difficult at all. Sure every once in a while I get all excited and pretend I've a direct rush to W. 27th and I've got to make time, and then I run a few reds. But on the whole It has been very easy to just adapt to the p-town culture and wait for the light like our four-wheeled friends.
I've posted about this before --how Portland is a little uptight when it comes to such things. Here you will get called out by other cyclists, motorists, --lots of people feel it is their place to be your mother.
Whereas in NY the modus operandi of virtually every cyclist amounted to, to quote (I think) Lucas Brunelle, "there is no law but the laws of physics."
Anyway it hasn't been difficult at all. Sure every once in a while I get all excited and pretend I've a direct rush to W. 27th and I've got to make time, and then I run a few reds. But on the whole It has been very easy to just adapt to the p-town culture and wait for the light like our four-wheeled friends.
Thursday, October 9, 2008
Irony and I wish I had a camera
I need to buy a camera. I'm always seeing things that I want to take a picture of.
For example, a couple of days ago on 47th and Sandy I saw a bit of a strange scene.
First, some guy pulled up to the stoplight on a fixed gear conversion bike and put his foot down.
Then, moments later, a spandex clad roadie on a high end racing bike pulled up right behind him and did a track stand until the light changed.
I wished a had had a picture because it was really irony personified.
For example, a couple of days ago on 47th and Sandy I saw a bit of a strange scene.
First, some guy pulled up to the stoplight on a fixed gear conversion bike and put his foot down.
Then, moments later, a spandex clad roadie on a high end racing bike pulled up right behind him and did a track stand until the light changed.
I wished a had had a picture because it was really irony personified.
Sunday, October 5, 2008
Forget the hockey moms, what about the tandem track racing moms?
Keep watching till a little after two minutes in. It gets exciting.
Friday, October 3, 2008
Fenderriffic
It poured mostly all day today and I spent some time putting fenders on my bike. The best fenders I have are a little too tight for my 35cm tire setup but I have mismatched older ones (without any hardware or fender stays) that are wider that I'll to try and modify so they'll work with the fender stays I have.
It's a a good thing I made it back to P-town in time for the rainy season.
I wouldn't have wanted to miss it.
It's a a good thing I made it back to P-town in time for the rainy season.
I wouldn't have wanted to miss it.
found a photo on the internets
I was trying to find a photo of Eighth Avenue pedestrian traffic when I came across this:
...Kind of a neat picture.
...Kind of a neat picture.
No posts for two months = lame
One problem with Portland is that it's too easy to slip right back into like you were never gone. Then, suddenly, five more years have passed and what happened in the meantime?
Riding home from work here is worlds away from commuting home in Manhattan. I can remember riding up eighth avenue at rush hour, when the sidewalks would literally overflow with pedestrians into the bike lane and sometimes even the car lanes. --It was nuts. And I remember how excited I was to have found that pathetic little fir tree in downtown Manhattan. Portland, on the other hand, has no shortage of urban forests.
Here's a picture of Berrydale Park near 92nd and Hawthorne.
A view like the above is so common in Portland, and the Douglas Firs are so majestic. It's a far, far cry from the steaming manhole covers and blaring horns that were the norm as I used to fight my way through midtown and Columbus Circle and then further uptown along Central Park West.
The thing is that I must be insane, because I find myself wanting to move back to the city.
Riding home from work here is worlds away from commuting home in Manhattan. I can remember riding up eighth avenue at rush hour, when the sidewalks would literally overflow with pedestrians into the bike lane and sometimes even the car lanes. --It was nuts. And I remember how excited I was to have found that pathetic little fir tree in downtown Manhattan. Portland, on the other hand, has no shortage of urban forests.
Here's a picture of Berrydale Park near 92nd and Hawthorne.
A view like the above is so common in Portland, and the Douglas Firs are so majestic. It's a far, far cry from the steaming manhole covers and blaring horns that were the norm as I used to fight my way through midtown and Columbus Circle and then further uptown along Central Park West.The thing is that I must be insane, because I find myself wanting to move back to the city.
Monday, July 28, 2008
Found a Fir Tree: deal with it.
I found a fir tree in the city.
Weak, Manhattan. Is this the best you can do?
Monday, July 14, 2008
Silly People
One of the fun things about delivering packages all day is getting to go inside the various buildings. It's like a tour of "things you could have done with your life." Oh, look: an architect. Or, what's this here? A businessman.
It's just interesting to see people in their natural habitat, doing things that I'll almost certainly never do. For instance, did you know there was a New York State fashion school? It's on W. 27, or somewhere down there. --An actual state-funded school for fashion. The Fashion Institute of Technology. --No joke.
The other crazy thing about the different buildings is the way they label the floors. I remember reading in one of those Feynman memoirs from way back when about how some of the buildings in New York don't label floor 13. This was old time Feynman memories, from before WWII, I think, so I always assumed that that kind of superstitious nonsense was a relic from the past.
But it isn't. The first time I saw an elevator go from floor 12, to 12A, to 14, I thought: ha, that's funny, they must've forgotten to change the label on the elevator, just like in the Feynman books. But then I saw it again, and again, and again. --All over town. Sometimes the floors go from 12 to 14. Or sometimes floor 13 is labeled 12A. This is really funny to me, because there isn't really any excuse for it. It's not as if they can say: "Oh, when this building was built people were more superstitious." Because all they would have to do is change the label.
I want to find somebody I can shake by the collar and say: Wake up! Floor thirteen still exists, dummy. You just aren't calling it 13.
It's just interesting to see people in their natural habitat, doing things that I'll almost certainly never do. For instance, did you know there was a New York State fashion school? It's on W. 27, or somewhere down there. --An actual state-funded school for fashion. The Fashion Institute of Technology. --No joke.
The other crazy thing about the different buildings is the way they label the floors. I remember reading in one of those Feynman memoirs from way back when about how some of the buildings in New York don't label floor 13. This was old time Feynman memories, from before WWII, I think, so I always assumed that that kind of superstitious nonsense was a relic from the past.
But it isn't. The first time I saw an elevator go from floor 12, to 12A, to 14, I thought: ha, that's funny, they must've forgotten to change the label on the elevator, just like in the Feynman books. But then I saw it again, and again, and again. --All over town. Sometimes the floors go from 12 to 14. Or sometimes floor 13 is labeled 12A. This is really funny to me, because there isn't really any excuse for it. It's not as if they can say: "Oh, when this building was built people were more superstitious." Because all they would have to do is change the label.
I want to find somebody I can shake by the collar and say: Wake up! Floor thirteen still exists, dummy. You just aren't calling it 13.
Saturday, July 12, 2008
pillars of the community: neighborhood bikes
Whenever I'm out and about, there are three things I check out, in the following order:
1, Bicycles
2, Women
3, Dogs
Although there are some beautiful women in Manhattan, it might be a little creepy to go around taking peoples pictures and posting them on the internet. And, anyway, since this is mostly a blog about cycling, in the spirit of number one, here are some bicycles I've notice parked around the 'hood.
I love how pizzas are delivered by bicycle around here. The whole idea of a utility bike is somehow just very civilized. What you see here with the modified Wald baskets (I think,) is pretty typical. These bikes are parked outside a pizza joint on 110th and Amsterdam.
...
This guy is something of a neighborhood stalwart. It's been parked on 112th and Broadway (in front of the Seinfeld restaurant) since I've been in NY. Notice how only the front wheel is locked up with a crappy cable lock. Somehow nobody has stolen it yet. It's there literally all the time. I think so, anyway. I don't sit around watching it for 24 hrs. a day or anything. I can't help but wonder if it isn't some sociology study by some Columbia kids or something.
I have to say I'm a little underwhelmed by the allegedly cutthroat NY bike thieves. Some crafty bike thief could put a track wheel on this, call it vintage, and make a tidy sum on craigslist.
This bike is a little out of place in the neighborhood. It was parked like this on Broadway pretty much all day today. I don't know what the story is here. I don't think there's a velodrome nearby. Maybe the owner just wanted to take his shirt off and get a tan.
Hmmm.
Contrast fancy pants up there with this bike on 112th. Abandoned?
It would seem so. But at any rate still locked up. Everything but the rear wheel, at least. For some reason no one has stolen that.
1, Bicycles
2, Women
3, Dogs
Although there are some beautiful women in Manhattan, it might be a little creepy to go around taking peoples pictures and posting them on the internet. And, anyway, since this is mostly a blog about cycling, in the spirit of number one, here are some bicycles I've notice parked around the 'hood.
I love how pizzas are delivered by bicycle around here. The whole idea of a utility bike is somehow just very civilized. What you see here with the modified Wald baskets (I think,) is pretty typical. These bikes are parked outside a pizza joint on 110th and Amsterdam.
...
This guy is something of a neighborhood stalwart. It's been parked on 112th and Broadway (in front of the Seinfeld restaurant) since I've been in NY. Notice how only the front wheel is locked up with a crappy cable lock. Somehow nobody has stolen it yet. It's there literally all the time. I think so, anyway. I don't sit around watching it for 24 hrs. a day or anything. I can't help but wonder if it isn't some sociology study by some Columbia kids or something.
I have to say I'm a little underwhelmed by the allegedly cutthroat NY bike thieves. Some crafty bike thief could put a track wheel on this, call it vintage, and make a tidy sum on craigslist.
This bike is a little out of place in the neighborhood. It was parked like this on Broadway pretty much all day today. I don't know what the story is here. I don't think there's a velodrome nearby. Maybe the owner just wanted to take his shirt off and get a tan.
Hmmm.
Contrast fancy pants up there with this bike on 112th. Abandoned?It would seem so. But at any rate still locked up. Everything but the rear wheel, at least. For some reason no one has stolen that.
Wednesday, July 2, 2008
the working cyclist
I haven't posted here in a month or two, which is too long. I was busy moving across the continent is all. But anyway I'm in New York now and I want to chronicle if anything interesting happens.
I got a job as a messenger last week. --Everyone I've told has been surprised. How did you do that, you don't even know your way around? And it's true, I don't know my way around, but I didn't tell the courier company that. I think they just needed bodies. I mean, I walked in and got hired the same day. Also I don't think it pays that much. Not to mention it's dangerous.
And after a week and a half now I feel I'm finding a bit of a groove. Navigating my way around a little better and learning tricks to save time. Today I had "direct rush." from somewhere around W 25 or so to 161 6th Ave. I knocked it out right away, and when the dispatcher called to give me another delivery going that way he was surprised that I had already dropped the first one off and said something like "man, you're good." --So that was kind of nice.
I admit I was a bit naive when I first started. I would do things like figure out which streets were one-way east, and which were one-way west, and then I'd circle the block to make deliveries. Yeah, that M.O. lasted about two days. --You have to sometimes go the wrong way, or you'd never get anything done. It's not a first option, but it can be perfectly safe, as long as you don't forget that you're going the wrong way.
The cops here don't give a rip, either. You can run red lights all day long, they don't care. In Portland, the police have nothing to do, so they waste time harassing cyclists. If you run a red light, the whole town would have a fit. There would be a huge discussion on bikeportland.org, or the shift email list. Don't believe me? Here's an example. In Manhattan, the police have bigger fish to fry. --I don't mean to talk trash about Portland. I love Portland, but that's just the way things are.
Also, for a while I was trying to imitate a NY accent. --Just for fun. But then today some guy said, "Where's your accent from? Is that Polish?" I think from now on I'll just talk like a normal Oregonian.
I got a job as a messenger last week. --Everyone I've told has been surprised. How did you do that, you don't even know your way around? And it's true, I don't know my way around, but I didn't tell the courier company that. I think they just needed bodies. I mean, I walked in and got hired the same day. Also I don't think it pays that much. Not to mention it's dangerous.
And after a week and a half now I feel I'm finding a bit of a groove. Navigating my way around a little better and learning tricks to save time. Today I had "direct rush." from somewhere around W 25 or so to 161 6th Ave. I knocked it out right away, and when the dispatcher called to give me another delivery going that way he was surprised that I had already dropped the first one off and said something like "man, you're good." --So that was kind of nice.
I admit I was a bit naive when I first started. I would do things like figure out which streets were one-way east, and which were one-way west, and then I'd circle the block to make deliveries. Yeah, that M.O. lasted about two days. --You have to sometimes go the wrong way, or you'd never get anything done. It's not a first option, but it can be perfectly safe, as long as you don't forget that you're going the wrong way.
The cops here don't give a rip, either. You can run red lights all day long, they don't care. In Portland, the police have nothing to do, so they waste time harassing cyclists. If you run a red light, the whole town would have a fit. There would be a huge discussion on bikeportland.org, or the shift email list. Don't believe me? Here's an example. In Manhattan, the police have bigger fish to fry. --I don't mean to talk trash about Portland. I love Portland, but that's just the way things are.
Also, for a while I was trying to imitate a NY accent. --Just for fun. But then today some guy said, "Where's your accent from? Is that Polish?" I think from now on I'll just talk like a normal Oregonian.
Thursday, June 5, 2008
Friday, May 23, 2008
In other news: some guy makes rough estimate
BikePortland had a story the other day about the Obama rally at Waterfront Park.
Although the crowd was a little too big for any real hobnobbing with Barack, it was still a worthwhile way to spend a Sunday afternoon.
The sheer number of bikes parked down there, in particular, was pretty neat to see. At the time, I did a very rough estimate of the number of bikes parked along the stone railing, and posted it (and my method of coming about that estimate) in the comments of the bikeportland story (I post over there under the screen name Qwendolyn.)
Well tonight I was browsing streetsblog, and came across this story about the Portland Obama rally and Sam Adams having won the mayoral race.
What took me a little by surprise is that Streetsblog repeated my 8000+ estimate of the number of bikes parked at the rally. They didn't say where they got that number but when I took a look back at the BikePortland.org story it had been updated with my estimate in the actual story.
I obviously don't care whether or not I'm credited for a rough estimate that took me 2 minutes to calculate, but it should at least be noted that it may not be the most accurate estimate in the history of mankind.
I suppose the moral is that a healthy dose of skepticism should be applied whenever you see people throwing out numbers without explaining where they got them.
Although the crowd was a little too big for any real hobnobbing with Barack, it was still a worthwhile way to spend a Sunday afternoon.
The sheer number of bikes parked down there, in particular, was pretty neat to see. At the time, I did a very rough estimate of the number of bikes parked along the stone railing, and posted it (and my method of coming about that estimate) in the comments of the bikeportland story (I post over there under the screen name Qwendolyn.)
Well tonight I was browsing streetsblog, and came across this story about the Portland Obama rally and Sam Adams having won the mayoral race.
What took me a little by surprise is that Streetsblog repeated my 8000+ estimate of the number of bikes parked at the rally. They didn't say where they got that number but when I took a look back at the BikePortland.org story it had been updated with my estimate in the actual story.
I obviously don't care whether or not I'm credited for a rough estimate that took me 2 minutes to calculate, but it should at least be noted that it may not be the most accurate estimate in the history of mankind.
I suppose the moral is that a healthy dose of skepticism should be applied whenever you see people throwing out numbers without explaining where they got them.
Wednesday, April 16, 2008
dandelions are the white trash flower bed
I imagine that when the inventor of the folding bicycle first showed it around to his friends there may have been some confusion about the whole idea.
Friend: Oh my god, I'm so sorry. You worked so hard on that, and now look at it.
Inventor of Folding Bicycle: No, no. It's supposed to collapse like that. That's what it does.
Friend: All that planning and time and hard work for nothing. So sad. What are you going to do now? Go back to grad school?
Inventor of Folding Bicycle: No, you dolt. That's how it works. It's a folding bicycle.
Friend: Oh.... Ummm, I don't get it.
The point of the extremely boring above dialogue is that sometimes an idea takes some getting used to but that don't give up just because you're misunderstood by your friends and contemporaries.
For example, when I custom build an accordion with three changes in the treble to switch between a mildly pleasant vibrato with 12 equal half steps between octaves on the first switch and fifths tuned in a perfect 3:2 ratio with half steps being the seventh root of 3 halves on the second switch, and a third switch where the half steps are the fourth root of 4 thirds and the third tones in the scale are tuned in a perfect 4:3 ratio then all you naysayers won't be laughing anymore.
No. No, you won't.
Friend: Oh my god, I'm so sorry. You worked so hard on that, and now look at it.
Inventor of Folding Bicycle: No, no. It's supposed to collapse like that. That's what it does.
Friend: All that planning and time and hard work for nothing. So sad. What are you going to do now? Go back to grad school?
Inventor of Folding Bicycle: No, you dolt. That's how it works. It's a folding bicycle.
Friend: Oh.... Ummm, I don't get it.
The point of the extremely boring above dialogue is that sometimes an idea takes some getting used to but that don't give up just because you're misunderstood by your friends and contemporaries.
For example, when I custom build an accordion with three changes in the treble to switch between a mildly pleasant vibrato with 12 equal half steps between octaves on the first switch and fifths tuned in a perfect 3:2 ratio with half steps being the seventh root of 3 halves on the second switch, and a third switch where the half steps are the fourth root of 4 thirds and the third tones in the scale are tuned in a perfect 4:3 ratio then all you naysayers won't be laughing anymore.
No. No, you won't.
Thursday, April 10, 2008
Advice for you
If you want to avoid pedal strike on your fixed gear (which I'm sure that you, sensible reader, most certainly do) one thing to take into account is your gear ratio.
Imagine a stretch of curb with an obstacle positioned briefly alongside it (this could be anything: a speed bump, an old lady with a walker, or perhaps a small infant (and really, aren't all infants small).)
Imagine further that the gap between the curb and the obstacle is wide enough to fit the bicycle tires but not wide enough to guarantee that your pedal won't hit the curb. --A certain percentage of your pedal arc will be too wide to fit in the gap.
Assume that the position of the pedals when you arrive at the gap is a uniform random variable (meaning all positions will be equally likely.) Then, whatever your gear ratio, the percentage of your pedal arc that is too wide for the gap will be the probability that your pedal is hitting the curb at any given time.
This is admittedly not all that profound and smacks of pretentious washed-up-math-major posturing. Which is what it is. The crucial insight comes, however, when you realize that if your gear inches are less than the length of the curb/obstacle gap, then your pedal is guaranteed to strike the curb. --You cannot get through the gap without making more than one complete revolution of the pedals, and part of your pedal revolution is too wide to get through.
Therefore, fixed-gear cyclists arriving at gaps between curbs and small infants (or whatever) can maximize the probability of successfully navigating such gaps by making their gear ratio as high as possible. For example, with an infinitely high gear ratio, one could potentially navigate between an infinitely long curb and infinitely long old lady and her walker.
...Just something to keep in mind while you're shopping for girl pants or listening to Sufjan Stevens.
Imagine a stretch of curb with an obstacle positioned briefly alongside it (this could be anything: a speed bump, an old lady with a walker, or perhaps a small infant (and really, aren't all infants small).)
Imagine further that the gap between the curb and the obstacle is wide enough to fit the bicycle tires but not wide enough to guarantee that your pedal won't hit the curb. --A certain percentage of your pedal arc will be too wide to fit in the gap.
Assume that the position of the pedals when you arrive at the gap is a uniform random variable (meaning all positions will be equally likely.) Then, whatever your gear ratio, the percentage of your pedal arc that is too wide for the gap will be the probability that your pedal is hitting the curb at any given time.
This is admittedly not all that profound and smacks of pretentious washed-up-math-major posturing. Which is what it is. The crucial insight comes, however, when you realize that if your gear inches are less than the length of the curb/obstacle gap, then your pedal is guaranteed to strike the curb. --You cannot get through the gap without making more than one complete revolution of the pedals, and part of your pedal revolution is too wide to get through.
Therefore, fixed-gear cyclists arriving at gaps between curbs and small infants (or whatever) can maximize the probability of successfully navigating such gaps by making their gear ratio as high as possible. For example, with an infinitely high gear ratio, one could potentially navigate between an infinitely long curb and infinitely long old lady and her walker.
...Just something to keep in mind while you're shopping for girl pants or listening to Sufjan Stevens.
A moral line in the sand
My editor's been hounding me to cut down on the math content. She says we're losing readership.
Me: Readership?
My Editor: Yeah.
Me: Readership?
My Editor: Yep. So can it with the heady math stuff, OK.
Me: Readership? Wait, wait. I'm sorry. Heady?
Her claim is that the number of readers gets cut in half for every post with any math in it. I told her that's good, --pretty soon we're going to be bailed out by the fed for two dollars a share.
My Editor: I don't even exist. This is a free blogspot account. You do what you want. I'm out of here.
Me: I will not water down my content. The huddled masses are clamoring for a blog solution combining a healthy dose of mathematical musings with a fun size portion of cycling punditry. They will not be denied.
Me: Readership?
My Editor: Yeah.
Me: Readership?
My Editor: Yep. So can it with the heady math stuff, OK.
Me: Readership? Wait, wait. I'm sorry. Heady?
Her claim is that the number of readers gets cut in half for every post with any math in it. I told her that's good, --pretty soon we're going to be bailed out by the fed for two dollars a share.
My Editor: I don't even exist. This is a free blogspot account. You do what you want. I'm out of here.
Me: I will not water down my content. The huddled masses are clamoring for a blog solution combining a healthy dose of mathematical musings with a fun size portion of cycling punditry. They will not be denied.
Wednesday, April 9, 2008
If only
One thing fixed gear riders have noticed is that if the number of teeth on your chainring and the number of teeth on your rear-cog are relatively prime, then for any given such combination you will maximize the number of skid patches on your tire. This is good because you will have to replace your tire less often.
What's more, you can achieve more versatility by making the number of teeth on the chainring prime. That way, you can have a one or two tooth difference in cog size on the flip-flop, (which will give a greater difference in gear ratio for each side than the same difference in teeth on the chainring,) --and no matter what number of teeth you have on either cog, it will be relatively prime with the front chainring. This is because any number of teeth on the rear-cog will be relatively prime with the (prime) number of teeth on the chainring.
As Stephen Colbert once said to our bow-tie sporting local congressperson: this borders on interesting.
If only there were some device, --some kind of mechanism that would allow you to regulate chain tension as well as achieve different gear ratios without flipping your wheel around or prime-factoring your chainring. Or maybe some other sort of invention that allowed you to brake without wearing out your tire.
Maybe science can come up with something. Science has done good things in the past, haven't they?
Yes. Yes, they have.
What's more, you can achieve more versatility by making the number of teeth on the chainring prime. That way, you can have a one or two tooth difference in cog size on the flip-flop, (which will give a greater difference in gear ratio for each side than the same difference in teeth on the chainring,) --and no matter what number of teeth you have on either cog, it will be relatively prime with the front chainring. This is because any number of teeth on the rear-cog will be relatively prime with the (prime) number of teeth on the chainring.
As Stephen Colbert once said to our bow-tie sporting local congressperson: this borders on interesting.
If only there were some device, --some kind of mechanism that would allow you to regulate chain tension as well as achieve different gear ratios without flipping your wheel around or prime-factoring your chainring. Or maybe some other sort of invention that allowed you to brake without wearing out your tire.
Maybe science can come up with something. Science has done good things in the past, haven't they?
Yes. Yes, they have.
Tuesday, April 8, 2008
That's what I thought too
Hey, what's the deal here? I thought this was going to be a blog about cycling.
this whole mortgage thing
By now it's old news that some of the big financial players misunderestimated the risk involved with buying a lot of sub-prime mortgages.
And, sure, we can second-guess after the fact --but if we had been there at the time who's to say we wouldn't have been buying up the crappy mortgages like hot-cakes ourselves. I know I do love me some hot-cakes.
Besides the occasional hankering for some hot-off-the-grittle whole-wheat pancakes, my only other claim to a bit of expertise in the matter is having failed the actuarial exam four times.
As Larry David would say:
Pretty, pretty good.
You'd be hard-pressed to find anybody who has topped that little bit of shameless perseverance. Way to go, me.
It has been a little while, but I was thinking about it and I do remember that theorem where the sum of the standard deviations is greater than the standard deviation of the sum. --Allegedly standard deviation measures risk, so the idea is that if you pool all the risk it's less risky.
That's the idea anyway.
And, sure, we can second-guess after the fact --but if we had been there at the time who's to say we wouldn't have been buying up the crappy mortgages like hot-cakes ourselves. I know I do love me some hot-cakes.
Besides the occasional hankering for some hot-off-the-grittle whole-wheat pancakes, my only other claim to a bit of expertise in the matter is having failed the actuarial exam four times.
As Larry David would say:
Pretty, pretty good.
You'd be hard-pressed to find anybody who has topped that little bit of shameless perseverance. Way to go, me.
It has been a little while, but I was thinking about it and I do remember that theorem where the sum of the standard deviations is greater than the standard deviation of the sum. --Allegedly standard deviation measures risk, so the idea is that if you pool all the risk it's less risky.
That's the idea anyway.
Subscribe to:
Posts (Atom)