Tire Pressure
#26
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Why not believe the more objective testing? The Silca calculator is probably a good starting point. If you play around with their online calculator you will note that it recommends lower pressures on worn or crappy roads. 110 psi is almost certainly too high.
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All this talk of “run what works for you” is a whole lot of horse feathers if you don’t do what everyone else does.
Now if you’ll excuse me—I have to go buy a carbon fiber disc brake bike while it’s still light out.
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Pretty sure my RR is less than a 700 x 38 running at 80 psi or whatever wheelbarrow tires are inflated to today.
All this talk of “run what works for you” is a whole lot of horse feathers if you don’t do what everyone else does.
Now if you’ll excuse me—I have to go buy a carbon fiber disc brake bike while it’s still light out.
All this talk of “run what works for you” is a whole lot of horse feathers if you don’t do what everyone else does.
Now if you’ll excuse me—I have to go buy a carbon fiber disc brake bike while it’s still light out.
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Which is why I qualified my "doing it wrong" with, "if you're interested in performance."
Don't confuse your perception with reality. They're slower, they have a smaller contact patch, and being "less cushy" is the conversion of forward momentum in to upwards momentum.
There's a wide range of optimal, depending upon the rider, the tires, the surface, etc, but 140psi on pavement is well outside of the feasibly optimal range.
Don't confuse your perception with reality. They're slower, they have a smaller contact patch, and being "less cushy" is the conversion of forward momentum in to upwards momentum.
There's a wide range of optimal, depending upon the rider, the tires, the surface, etc, but 140psi on pavement is well outside of the feasibly optimal range.
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How is it “absurdly high” if that’s 5 psi below the high of the recommended range?
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You do realize “smaller contact patch” = less friction = less rolling resistance?
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#38
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I just look at the sidewall of the tire and see what the manufacturer has imprinted on it. Currently running 700x32 tires and I pump them up to the recommended 80 psi max. I used to run 700x28 that had a max rating of 110 psi.
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You guys that think high pressure is fast because 'it feels fast' just don't get it. What you're feeling is the very definition of rolling resistance. If you're feeling every little bump and bit of texture it's because the bike AND you are going up and down. Not as efficient as if the bike AND you weren't going up and down. 'Feels' count for very little here, we're dealing with physics. Which are known as the LAWS of physics.
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In Newton's pendulum, the kinetic energy of the first ball is transmitted through all the balls to the last because they are perfectly elastic and very hard. If the balls were perfectly inelastic, the last ball would not move at all because all of the balls would have absorbed all the energy.
In a hard tire, all the energy is transmitted through and you can feel all the vertical bumps. Not only do you go up and down, you go forward.
In a soft tire, the rubber absorbs all the energy and reduces your forward motion. Try riding on grass and sand where the soft ground is absorbing all the energy. Then compare that with riding on concrete, asphalt or on a perfectly smooth and hard track of a velodrome. The hard surface transmits all your energy.
In a hard tire, all the energy is transmitted through and you can feel all the vertical bumps. Not only do you go up and down, you go forward.
In a soft tire, the rubber absorbs all the energy and reduces your forward motion. Try riding on grass and sand where the soft ground is absorbing all the energy. Then compare that with riding on concrete, asphalt or on a perfectly smooth and hard track of a velodrome. The hard surface transmits all your energy.
#41
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In a soft tire, the rubber absorbs all the energy and reduces your forward motion. Try riding on grass and sand where the soft ground is absorbing all the energy. Then compare that with riding on concrete, asphalt or on a perfectly smooth and hard track of a velodrome. The hard surface transmits all your energy.
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In Newton's pendulum, the kinetic energy of the first ball is transmitted through all the balls to the last because they are perfectly elastic and very hard. If the balls were perfectly inelastic, the last ball would not move at all because all of the balls would have absorbed all the energy.
Stick blobs of clay at all the contact points and try it for yourself.
Otto
Last edited by ofajen; 06-07-22 at 08:33 PM.
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Bro ride your own ride... I work with physicists all day (im at a national laboratory in group looking for dark matter), there are too many variables to math out the fastest tires. The only reliable test is one done in real world conditions. Some people enjoy thin hard tires.
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Bro ride your own ride... I work with physicists all day (im at a national laboratory in group looking for dark matter), there are too many variables to math out the fastest tires. The only reliable test is one done in real world conditions. Some people enjoy thin hard tires.
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