What keeps a bike upright?
https://www.nature.com/news/the-bicy...matics-1.20281
Of course this isn't for John or Frank who could fall down if they were sitting on the ground. |
What keeps a bike upright?
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What keeps a bike upright?
On Friday, January 4, 2019 at 12:28:54 PM UTC-5, Frank Krygowski wrote:
On 1/4/2019 11:37 AM, wrote: https://www.nature.com/news/the-bicy...matics-1.20281 Of course this isn't for John or Frank who could fall down if they were sitting on the ground. You're just reading that now?? -- - Frank Krygowski Seems to me that the guy has made a few basic false assumptions. Any bicycle I've ever seen with the front fork in it's proper position soon falls over after being pushed without a rider on it. I also think that the gyroscoptic force of rotating bicycle wheels keeping the bicycle upright is miniscule unless the wheels are turning at very high revolutions. I once saw a video on You Tube of a normal bike with the front fork reversed, and without a rider, that went quite a distance when pushed before toppling over. I think too that making a bicycle stable enough to be riderless might end up being extremely difficult to ride. Look at how even small changes in frame/trail geometry on a road bike creates quite different handling characteristics. Cheers |
What keeps a bike upright?
On Fri, 4 Jan 2019 12:28:50 -0500, Frank Krygowski
wrote: On 1/4/2019 11:37 AM, wrote: https://www.nature.com/news/the-bicy...matics-1.20281 Of course this isn't for John or Frank who could fall down if they were sitting on the ground. You're just reading that now?? Well, Tom is a little slow on the uptake. cheers, John B. |
What keeps a bike upright?
On Fri, 4 Jan 2019 10:43:12 -0800 (PST), Sir Ridesalot
wrote: On Friday, January 4, 2019 at 12:28:54 PM UTC-5, Frank Krygowski wrote: On 1/4/2019 11:37 AM, wrote: https://www.nature.com/news/the-bicy...matics-1.20281 Of course this isn't for John or Frank who could fall down if they were sitting on the ground. You're just reading that now?? -- - Frank Krygowski Seems to me that the guy has made a few basic false assumptions. Any bicycle I've ever seen with the front fork in it's proper position soon falls over after being pushed without a rider on it. I also think that the gyroscopic force of rotating bicycle wheels keeping the bicycle upright is miniscule unless the wheels are turning at very high revolutions. I once saw a video on You Tube of a normal bike with the front fork reversed, and without a rider, that went quite a distance when pushed before toppling over. I think too that making a bicycle stable enough to be riderless might end up being extremely difficult to ride. Look at how even small changes in frame/trail geometry on a road bike creates quite different handling characteristics. Cheers There has been a lot of research into what makes a bike stable. One paper I read described a bike that was built with a front fork that allowed the trail to be adjusted from a negative number to a rather large positive number and yes "trail" has a great effect on the (would one say) the longitudinal stability of a bike - how easily the fork turns, and during the same experiment it was "discovered" that BB height, vertical location of center of gravity, also effected this same stability. Bikes have also been built with counter rotating wheels which counter act the gyroscopic effect of the spinning wheels. My own guess is that bicycles require stability in at least two planes and so far no one seems to have built a bicycle that is completely stable. cheers, John B. |
What keeps a bike upright?
On Friday, January 4, 2019 at 3:41:22 PM UTC-8, John B. Slocomb wrote:
On Fri, 4 Jan 2019 10:43:12 -0800 (PST), Sir Ridesalot wrote: On Friday, January 4, 2019 at 12:28:54 PM UTC-5, Frank Krygowski wrote: On 1/4/2019 11:37 AM, wrote: https://www.nature.com/news/the-bicy...matics-1.20281 Of course this isn't for John or Frank who could fall down if they were sitting on the ground. You're just reading that now?? -- - Frank Krygowski Seems to me that the guy has made a few basic false assumptions. Any bicycle I've ever seen with the front fork in it's proper position soon falls over after being pushed without a rider on it. I also think that the gyroscopic force of rotating bicycle wheels keeping the bicycle upright is miniscule unless the wheels are turning at very high revolutions. I once saw a video on You Tube of a normal bike with the front fork reversed, and without a rider, that went quite a distance when pushed before toppling over. I think too that making a bicycle stable enough to be riderless might end up being extremely difficult to ride. Look at how even small changes in frame/trail geometry on a road bike creates quite different handling characteristics. Cheers There has been a lot of research into what makes a bike stable. One paper I read described a bike that was built with a front fork that allowed the trail to be adjusted from a negative number to a rather large positive number and yes "trail" has a great effect on the (would one say) the longitudinal stability of a bike - how easily the fork turns, and during the same experiment it was "discovered" that BB height, vertical location of center of gravity, also effected this same stability. Bikes have also been built with counter rotating wheels which counter act the gyroscopic effect of the spinning wheels. My own guess is that bicycles require stability in at least two planes and so far no one seems to have built a bicycle that is completely stable. cheers, John B. All you have to do is look at a Penny Farthing which had totally different geometry but not only was ridable but they raced them. That gives you some idea of just how odd a bicycle really is. |
What keeps a bike upright?
On Sat, 5 Jan 2019 10:29:06 -0800 (PST), wrote:
On Friday, January 4, 2019 at 3:41:22 PM UTC-8, John B. Slocomb wrote: On Fri, 4 Jan 2019 10:43:12 -0800 (PST), Sir Ridesalot wrote: On Friday, January 4, 2019 at 12:28:54 PM UTC-5, Frank Krygowski wrote: On 1/4/2019 11:37 AM, wrote: https://www.nature.com/news/the-bicy...matics-1.20281 Of course this isn't for John or Frank who could fall down if they were sitting on the ground. You're just reading that now?? -- - Frank Krygowski Seems to me that the guy has made a few basic false assumptions. Any bicycle I've ever seen with the front fork in it's proper position soon falls over after being pushed without a rider on it. I also think that the gyroscopic force of rotating bicycle wheels keeping the bicycle upright is miniscule unless the wheels are turning at very high revolutions. I once saw a video on You Tube of a normal bike with the front fork reversed, and without a rider, that went quite a distance when pushed before toppling over. I think too that making a bicycle stable enough to be riderless might end up being extremely difficult to ride. Look at how even small changes in frame/trail geometry on a road bike creates quite different handling characteristics. Cheers There has been a lot of research into what makes a bike stable. One paper I read described a bike that was built with a front fork that allowed the trail to be adjusted from a negative number to a rather large positive number and yes "trail" has a great effect on the (would one say) the longitudinal stability of a bike - how easily the fork turns, and during the same experiment it was "discovered" that BB height, vertical location of center of gravity, also effected this same stability. Bikes have also been built with counter rotating wheels which counter act the gyroscopic effect of the spinning wheels. My own guess is that bicycles require stability in at least two planes and so far no one seems to have built a bicycle that is completely stable. cheers, John B. All you have to do is look at a Penny Farthing which had totally different geometry but not only was ridable but they raced them. That gives you some idea of just how odd a bicycle really is. Ridable? A bloke rode one across the U.S. in 1884.... and today people brag when they ride down a gravel road. There was a discussion here about riding wheelers some time ago and Frank, I believe, described riding one and apparently they are easier to balance then the more modern bicycles. cheers, John B. |
What keeps a bike upright?
John B. Slocomb wrote:
On Sat, 5 Jan 2019 10:29:06 -0800 (PST), wrote: On Friday, January 4, 2019 at 3:41:22 PM UTC-8, John B. Slocomb wrote: On Fri, 4 Jan 2019 10:43:12 -0800 (PST), Sir Ridesalot wrote: On Friday, January 4, 2019 at 12:28:54 PM UTC-5, Frank Krygowski wrote: On 1/4/2019 11:37 AM, wrote: https://www.nature.com/news/the-bicy...matics-1.20281 Of course this isn't for John or Frank who could fall down if they were sitting on the ground. You're just reading that now?? -- - Frank Krygowski Seems to me that the guy has made a few basic false assumptions. Any bicycle I've ever seen with the front fork in it's proper position soon falls over after being pushed without a rider on it. I also think that the gyroscopic force of rotating bicycle wheels keeping the bicycle upright is miniscule unless the wheels are turning at very high revolutions. I once saw a video on You Tube of a normal bike with the front fork reversed, and without a rider, that went quite a distance when pushed before toppling over. I think too that making a bicycle stable enough to be riderless might end up being extremely difficult to ride. Look at how even small changes in frame/trail geometry on a road bike creates quite different handling characteristics. Cheers There has been a lot of research into what makes a bike stable. One paper I read described a bike that was built with a front fork that allowed the trail to be adjusted from a negative number to a rather large positive number and yes "trail" has a great effect on the (would one say) the longitudinal stability of a bike - how easily the fork turns, and during the same experiment it was "discovered" that BB height, vertical location of center of gravity, also effected this same stability. Bikes have also been built with counter rotating wheels which counter act the gyroscopic effect of the spinning wheels. My own guess is that bicycles require stability in at least two planes and so far no one seems to have built a bicycle that is completely stable. cheers, John B. All you have to do is look at a Penny Farthing which had totally different geometry but not only was ridable but they raced them. That gives you some idea of just how odd a bicycle really is. Ridable? A bloke rode one across the U.S. in 1884.... and today people brag when they ride down a gravel road. There was a discussion here about riding wheelers some time ago and Frank, I believe, described riding one and apparently they are easier to balance then the more modern bicycles. cheers, John B. Hard braking, coasting down steep hills and mounting/dismounting disregarded, of course :-) |
What keeps a bike upright?
On Sun, 06 Jan 2019 06:05:35 +0700, John B. Slocomb
wrote: On Sat, 5 Jan 2019 10:29:06 -0800 (PST), wrote: On Friday, January 4, 2019 at 3:41:22 PM UTC-8, John B. Slocomb wrote: On Fri, 4 Jan 2019 10:43:12 -0800 (PST), Sir Ridesalot wrote: On Friday, January 4, 2019 at 12:28:54 PM UTC-5, Frank Krygowski wrote: On 1/4/2019 11:37 AM, wrote: https://www.nature.com/news/the-bicy...matics-1.20281 Of course this isn't for John or Frank who could fall down if they were sitting on the ground. You're just reading that now?? -- - Frank Krygowski Seems to me that the guy has made a few basic false assumptions. Any bicycle I've ever seen with the front fork in it's proper position soon falls over after being pushed without a rider on it. I also think that the gyroscopic force of rotating bicycle wheels keeping the bicycle upright is miniscule unless the wheels are turning at very high revolutions. I once saw a video on You Tube of a normal bike with the front fork reversed, and without a rider, that went quite a distance when pushed before toppling over. I think too that making a bicycle stable enough to be riderless might end up being extremely difficult to ride. Look at how even small changes in frame/trail geometry on a road bike creates quite different handling characteristics. Cheers There has been a lot of research into what makes a bike stable. One paper I read described a bike that was built with a front fork that allowed the trail to be adjusted from a negative number to a rather large positive number and yes "trail" has a great effect on the (would one say) the longitudinal stability of a bike - how easily the fork turns, and during the same experiment it was "discovered" that BB height, vertical location of center of gravity, also effected this same stability. Bikes have also been built with counter rotating wheels which counter act the gyroscopic effect of the spinning wheels. My own guess is that bicycles require stability in at least two planes and so far no one seems to have built a bicycle that is completely stable. cheers, John B. All you have to do is look at a Penny Farthing which had totally different geometry but not only was ridable but they raced them. That gives you some idea of just how odd a bicycle really is. Ridable? A bloke rode one across the U.S. in 1884.... and today people brag when they ride down a gravel road. There was a discussion here about riding wheelers some time ago and Frank, I believe, described riding one and apparently they are easier to balance then the more modern bicycles. cheers, John B. Correction. should have read "riding high wheelers". cheers, John B. |
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