Bike Tires & Pressure

This is reference info for me:

  • Pavement Reference: 700c, 28mm @ 120psi for 300 LB ride weight, 60% rear
  • Cruiser Reference: 32er, 55mm @ 60psi for 310 LB ride weight, 70% rear
  • Off-Road Reference: 700c, 40mm @ 40psi for 180 LB ride weight, 60% rear

Slower speed, butt off the seat, you can go lower psi. You’d be risking pinch flats on longer rides, or unseating the bead in harder turns, etc

Tread pattern is coarse for rough terrain, fine for sand & hardpack, and smooth for pavement.

Higher pressure prevents tire flex, and is better on pavement. – Less shock absorption, grippy on soft, loose surface.

Lower pressure increases tire flex, which grips obstacles better. – Increased risk of pinch flats, or rolling off the rim.

General width preferences:

  • Hardpack or pavement – narrow to prevent drag
  • Sand, pea gravel, mud – wide to prevent sinking
  • loose, large gravel – wide to prevent pinch flats, throwing gravel, etc

Weight Distribution

  • Cruiser ~ 70% rear.
  • Mountain ~ 60% rear.
  • Race Road ~ 55% rear.

Proportional adjustments:

  • Narrower tire for larger diameter
  • Lower pressure for lower weight
  • Lower pressure for wider tire

Rim sizes:

  • 559mm = 26er
  • 584mm = 650b / 27.5″
  • 622mm = 700c / 29er
  • 686mm = 32er
  • 787mm = 36er

Dodger the Seventh

Author: /u/Morc35

Date: December, 2016

Subject: [WP] In the canine world, Humans are celestial beings who live for 500 years.

“Come!” The paw on the back of my head scratches through my fur. I snap at Dodger. He still treats me like a pup, and he is old. Old or not, he manages to catch me and roll me over. I bat at his chest and he snaps and growls near my ears until I surrender.

“Insolent pup,” he growls again as he lets me up.

“I’m not a pup!” I stand up and shake. “I have earned my name. The Lady gave me a name!”

“Dodger! Sapphire!” The girl’s voice from inside makes me perk up my ears.

“The Lady calls again. Come!” He turns back toward the house and trots over. I follow, and playfully snap at his golden tail. He ignores me because I am obeying.

The Lady opens the door. The youngest. Not quite 100 years yet. She just came of age last week, and there was a big celebration. I was quite popular that night, as her friends gave me many treats.

There was talk among the adults about her going away. She said I would go with her, and that made me happy. I wag my tail at her. The Lady pats my head, but then she kneels down and hugs Dodger. The Lady is crying.

“What’s wrong?” I ask her. She only reaches out and pats my head again. She doesn’t understand me yet. Not like the Master. The Master knows what we say. He understands Dodger more easily.

And then I notice that Dodger is not wagging his tail. He is also sad.

“Dodger?” I demand. I muscle my way into the hug and lick the Lady’s face. She laughs a little.

“Dodger, what’s wrong?”

“I have to go see the Master,” he says. He breaks away from the hug and leaves me with the Lady, who hugs me now instead.

I sniff her. She smells of the chemicals that Master smells like all the time now. I listen. I can hear the Mistress talking, talking to the Peddler of the chemicals. I nudge out of the hug to follow Dodger, up the stairs, up to Master’s room.

“Hey Sapphire,” says the Mistress when I enter. She rubs me behind the ears the way I like. I tell her thank you.

“Beautiful Husky,” says the Peddler. I greet him and he pets me. He seems all right, but for the odd smell.

“She belongs to my granddaughter.” The Mistress’s voice sounds odd, like she is in distress, but I smell no danger.

“Ah.” The Peddler is packing up. “If you need anything else…”

“Thank you.” The Mistress walks out with him.

Dodger is on the bed. He lays his head on Master’s chest, who looks asleep. The chemicals make me want to sneeze, but Dodger had told me that is disrespectful.

There’s another smell too: it’s been present for a long time, but today it is stronger than before.

I walk up to the side of the bed. “Dodger!” I speak loudly to get his attention.

He opens his big brown eyes. “Quiet, pup,” he says. “And go away.”

“No! Tell me what is going on. Why does the Master smell like this? Why is my Lady crying?” I put my paws on the bed to look at Master. His skin is very sallow and thin. The veins stand out.

“I am the Seventh,” says Dodger. He lifts his head from Master’s chest. “My family was made part of the Master’s family generations ago, when he was just a pup.”

Dodger looks at his Master’s face. “The First was named Dodger as well. He named me, knowing I would be the last.”

“The last?” I whine. “Dodger, what are you talking about?”

Dodger sighs. “You’re too young to understand.”

“I am not a puppy!” I say it loudly. “I am not!”

The Master opens his eyes, and I wonder if I have made a mistake. But he laughs and reaches out to scratch my ears. Like the Mistress, he knows how to scratch properly.

“Hullo, Sapphire,” he says. I wag my tail. “Be a good dog for Jenny, mm?”

“I will,” I tell him. I feel Dodger looking at me, all solemn.

“Good girl,” says Master. “I don’t have long before I go. Dodger will take care of me.”

I hear a car pull up the driveway outside. It’s a large one. I run to the window and look out: it’s big and white, and strange humans in uniform get out. The Mistress begins to talk with them. I run back to the bed.

I look at Dodger. “He can’t leave. You can’t leave!” I whine.

“Hey, hey,” says Master. He catches me near the ears again, gently. “I told you, Dodger will take care of me.”

I whine at them both. “You can’t leave!”

The men come upstairs with a bed on wheels. The Lady comes with them and takes me aside.

“Gotta move the dog.”

“I’ll move him,” says the Mistress. She lifts Dodger off the bed. He seems older than he did a little while ago. I whine at the Lady, but she just holds me and cries.

“He can’t leave!” I tell her, but she doesn’t understand yet. “They won’t bring him back!”

But he does leave. The Lady just holds me and weeps while the vehicles drive away.

We go downstairs and outside. Dodger walks down the driveway, following the vehicles.

“Dodger, wait!” I strain against the Lady’s hands. She calls for Dodger, and he waits a moment. I get free.

“Dodger, we have to bring the Master back!” I tell him. I could still hear the vehicles on the road. The Lady was running up behind me.

He wags his tail at me. “He told you to be a good dog and take care of the Lady. Be good, Sapphire.” He licks my face and runs off, golden fur shining in the sunlight.

Lady holds onto me and calls for Dodger, but he disobeys. I had never seen him disobey before. He had never called me by my name before.

I only saw Dodger one more time: we found him at the meadow where the Master’s body was laid, curled against the crossed stone that marked it.

He was the Seventh of his family. I am the First of mine.


A few years ago, I was in an area where white is a serious minority. I wanted to catch a movie. For a hundred miles around, I was part of a tiny minority. In visual range, I was THE white guy.

I walked around the mall a bit, but nothing caught my eye. I went to the box office, and could not get attention. No one would make eye contact with me. I asked for a ticket, and I was told “We don’t have a ticket for you.” Others were getting their tickets, just not me.

Some people would smile, and some would frown. Lots of suspicious looks, but lots of people who just knew I was an outsider, but it did not matter. Fragments of resentment of my outsider money were sprinkled around the edges.

This was temporary. Also, not everywhere was like that.

I got a cab, and went back to my hotel. Taxi driver was social and nice, but he was used to being around every kind if person. A customer is a customer to him.

My favorite food place didn’t care, other than a little squinting when accent differences had to be worked out. Their customers ran the gamut too.

But I got to go back home.

What if every single day was like this How would you react? How long would it take you to snap at someone for mistreating you because you’re an outsider?

Would you yell at someone when you are the only one of “your kind” in a sea of others? Would you feel safe?

What risks do you have in being the outsider that no one REALLY would be too upset about seeing you mistreated?

Who’s your chaperone? Who vouches for you as an outsider that’s okay?

Don’t let people be an outsider. Invite them in. Don’t hide from the awkward feeling. We’re all one big, extended family. Invite your distant cousin to sit with you. Hear a story, and do not worry that your life is different, or theirs is different.

Experience variety, not uniformity. Forgive the people who don’t do things “the right way” and above all else, remember the feeling of love. Feeling tense? Remember love. Frustrated? Overlay love. Angry? Love.

You can love without giving up what you need too. It just helps not give too much hassle to others who are probably feeling just as frustrated.

I may not always understand everything that’s going on, but you’re all my cousins. I hate to see you fight. Let’s get out of here and grab some food.

Biology Rambles with Khai

biology = whole organisms
microbiology = whole tiny organisms
cellular biology = whole cells of complex organisms
molecular biology = The machinery inside of cells
biochemistry = The chemicals of organisms, both inside and outside of cells
organic chemistry = chemistry involving carbon and hydrogen.

There’s more chemistry, and underlying chemistry is physics. Biology is an application of chemistry, and chemistry is an application of physics.

When you look at molecular biology, you see what looks like program counters and 3d printers. Most of the bits inside of cells are literally physical machines, aided along by the right shape to have a static or magnetic charge necessary to pull the right pieces out of the semi-random soup and move, attach, or detach them.

When you exercise, you literally dump calcium into pockets in a muscle cell, and those fit into a lock on a little machine that ratchets down a little rope, each click caused by an ATP molecule floating in, connecting, getting snapped, and having a tiny bit of electric charge transferred.

The fun thing is that ATP is also required to pump the calcium out of that little pocket, so when you’ve depleted ATP. There is a complex loop for making ATP, and a whole of of ways to keep that cycle (ctric acid or Krebs cycle) going, but the fastest way to make ATP is oxygen and glucose.

Oxygen input often lags behind, and you can always burn up oxygen faster than you can replenish it. When this happens, muscle cells get stuck contracted, and they keep trying to contract, competing for ATP in this depleted state. This is one of the ways a muscle cramp occurs.

This rambling brought to you by brain inputs triggered by talking to Khai about his AP biology test today, and how excited he is about all of the machinery inside of cells.

Class-M Asteroids

John W. posted about a Voyager episode (Emanations) where they found a Class-M Asteroid, and the question came up as to whether such a thing would even be possible.

In the episode, there were multiple Class-M asteroids around a Class-D Planet. Class-D is a small, rocky, barren planet, and Class-M means nickel-iron core, water, atmosphere, and overall suitable for human life.

This sent me off into research into what the minimum size might be for a human-habitable planet. Sea Level Pressure on Earth is 101.3 kPa, with 21% Oxygen. Minimum partial pressure of oxygen is 16 kPa, below which we cannot adapt. (15 kPa we lose cognitive functions, peripheral vision, and it gets worse the lower it goes.)

Pure oxygen atmosphere at 16kPa is not feasible either, because of dehydration and fire risks, plus oxygen toxicity. Bump up to 25% nitrogen to mitigate that. We also need a little moisture, at least 30% RH. At room temperature, we’re looking at another 1kPa.

Lastly, we need a buffer, because we’ll breathe out CO2, and cannot have more than 5%, though Earth normal is 0.04kPa. In a spacecraft, the buffer would depend on air circulation, reaction times, etc..Mir used 34kPa total atmospheric pressure, with 25% Nitrogen, 75% oxygen, and the CO2 and H2O were under 1% absolute.

On a dwarf planet or planet, the buffer would be the difference in pressures across the habitable zones of the planet. Maybe the highest peak would be 14kPa O2, maybe 21kPa total. Maybe the lowest trench would be 36kPa total, and 24kPa O2.

For a third pressure, we’re looking at a third of surface gravity. Assuming similar density to Earth, this could be about the size of Mercury. You still want a molten core, so you can have a magnetosphere. Either the rock is young (relatively speaking), or it’s a moon for tidal heating. The other options of high radioactivity, or much closer to the star, have issues for survivability.

With a gravity of around 3.3m/s, and a 34 kPa mean surface air pressure, humans would be limited to the bottom 4km of atmosphere. That’s totally reasonable. Maybe people get altitude sickness at 2km instead of 6-7km. Fine.

Planet diameter is, again, close to a third, more like 38-39%. So, we’re talking about 4900 km in diameter, and about 3.3E23 kg (about 5.5% of Earth). Our largest known asteroid is 1000km, and our largest known dwarf planet is 2600km.

For our solarsystem, a “Class M” asteroid would not be possible. If you get big enough, you move from asteroid to dwarf planet, though this term was not in use during that part of Voyager’s production. However, if it were big, they would have just called it a small planet, or even a moon since they’re orbiting a Class-D planet. NOTE: We have M-Type asteroids, which a re “metallic”. Ceres is a G-Type, which is carbon rich.

If there were a higher density core, you could reduce the size requirements. Remember that asteroids are basically shattered planets, or proto-planets that never could accrete, so you could have one that used to be mostly core material. The earth is 35% iron, 30% oxygen, 15% silicon, 13% magnesium, and 7% other stuff by mass.

Something with higher percentages of other stuff, such as late generation supernovae fragments might be possible. You could get three times the density out of things like Osmium, Platinum, and Gold without being toxic, though at some point, you’re looking at terraforming rather than evolved life, and it would be extra extra rare.

You couldn’t just do a 2600km 60% iron planetoid, because you wouldn’t be able to have enough silicate to protect the surface. The planet would cool too quickly unless it were close to the star (like Mercury). You’d have a very hot side, and a very cold side, or a very narrow window of access on astronomical and geological scales. It would be very magnetic (and conductive), and very reactive with water (part of Class-M is lots of water). The limit is probably somewhere around 40%. Even 43% is only 20-30% increased density. Even Mercury at 65% is too big to be even a Dwarf Planet. The density here is just not enough to bring gravity up to our target on a sub-3000km body.

You might be able to scrape by with 25% gravity, and a breathing apparatus, or if it were a really young planet, or had some other source for keeping the atmosphere relatively thick, but that gets so much more difficult to find AND call “Class-M”.

A Chthonian planet that got shattered by impact might work, if it were somehow put into a reasonable orbit. It could have very high density for a small core, 4x that of the Earth. But, they get that size by being a gas giant, then having the atmosphere stripped by being in too close of an orbit to a star. So then, it would have to be shattered, and one of those pieces would have to be ejected into a stable orbit inside of the habitable zone. That really means TWO collisions, one to transfer, and one to remove eccentricity. Not very likely, but maybe even smaller than Ceres might work. You’d need a more radioactive core, otherwise the planet would cool way too quickly. But, a radioactive core, on a shattered planetoid, would have a radioactive surface. Not Class-M.

A planet that had a Platinum inner core, and iron outer core might work. I’m thinking 30% Platinum, 20% iron, 20% oxygen, 12% silicon, 8% magnesium, and 10% other stuff (lots of carbon since it’s a smaller planet) could totally work on a 1200km planetoid. Though, this type of body would not really be a “Class-M” body by Trek standards (nickel-iron core), but it might be close enough. “Exotic Class-M” maybe. Might be an issue for heavy metal poisoning, since not all of the increased platinum would be in the core. Excess surface level might mean excess platinum salts… etc.

We still have to be concerned with loss of atmosphere through interaction with other asteroids, solar radiation, maintainingthe magnetic field, etc. The planet would not be habitable for nearly as long, and probably would not evolve life on its own. This asteroid did not. The only life were dead bodies (basically a cemetery planetoid). It’s possible even the atmosphere came from the subspace voids, though why the moons had atmospheres, but the central planet did not, does not seem rational to me. The lower pressure means water boils at 60C, which limits our range of surface temperatures (and increases cooking times!)

I did not calculate the scale height, nor any of the stuff to get exact with all of this. I might be off. This is just my mental gymnastics after too much dinner caffeine.

Tea Tree Soap 2018

Soap is done. It processed really fast, which scares me a little. I did use a much better stick blender. The pH came out a perfect 10 on one strip, and the other kind a 9.9.
I worry I’ll have trouble with it slumping whenever I remove the molds. I’m going to let it use up counter space in the kitchen until mid-week, and if it’s still soft, I’ll chill it before freeing it. I should have made this batch in January.
Anyway, I’m hopeful, though I overestimated the mold capacity. My old molds have self destructed (HDPE pipe, split), so I have some new, silicone ones. I used three, plus four Solo cups. Don’t judge. This is SCIENCE! 

Note to self, 3L of molds will not hold the soap created from 3L of oils, because, you know, another liter of water, plus some additives, plus the steam trapped in the soap during casting.  (Those molds were domed over with excess soap, and I tapped repeatedly to settle the bubbles.)

ps, I only burned myself once with a glob of molten soap!

If my brain were a CPU

5GHz, one core, 32 stage pipeline, multiple level branch predictors, out of order execution,

complete pipeline and cache flush on context switch.

64MB level-1 cache

No Level 2 cache

8 bit memory bus, with a 128-bit page select

All devices are memory mapped.

No I/O bus.

Fans and heat sinks clogged with dust.

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What is Evil?

What is evil? It’s not some force, roaming the land. It is a dark spot inside each of us. It’s an absence of love.

Be a better person. Don’t take joy in someone else suffering for their faults. Protect yourself, and those who are unable to protect themselves, and fill the rest of your heart with love and compassion.

Yes, we all get angry, frustrated, and generally are all horrible on the inside sometimes. That’s okay, but it’s not okay to wallow in it. It’s our responsibility to interrupt those feelings, and try to remember better ones. Try to be in a way that creates those better ones.


Today, at 8:22am, I turned 42 years old. I set up a mini-monitor and airflow for the new server location. I’m really happy with all that. Planted some squash. Watched about half of “Kill Switch”, a FPS style sci-fi movie. I made some lemon battery videos. I had lunch with my sister. I had cupcakes and coffee with Erica and Khai. I sync’d up with my team lead over the phone. All of that in a different order. Lastly, I’m about to go watch Max’s marching band performance, to see their progression. This has been a nice, chill day so far.

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