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#21
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Tomorrow's Bicycle Drive?
On Thu, 6 Jun 2019 09:11:13 -0700 (PDT), Sir Ridesalot
wrote: On Sunday, June 2, 2019 at 5:49:03 AM UTC-4, John B. Slocomb wrote: See https://www.youtube.com/watch?v=-9gQ1KRhesM In the narration he mentions that a 24 speed gear set, or even more, would be perfectly feasible. No wires, no cables, either. -- Cheers, John B. I can just imaging what road grit when it rains will do to those exposed bearings and interface. Can we say RAPID wear? Cheers Probably about the same as those exposed chains and sprockets when it rains and they get all muddy :-) -- cheers, John B. |
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#22
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Tomorrow's Bicycle Drive?
On Thu, 6 Jun 2019 13:15:10 -0700 (PDT), Tom Kunich
wrote: On Thursday, June 6, 2019 at 9:11:17 AM UTC-7, Sir Ridesalot wrote: On Sunday, June 2, 2019 at 5:49:03 AM UTC-4, John B. Slocomb wrote: See https://www.youtube.com/watch?v=-9gQ1KRhesM In the narration he mentions that a 24 speed gear set, or even more, would be perfectly feasible. No wires, no cables, either. -- Cheers, John B. I can just imaging what road grit when it rains will do to those exposed bearings and interface. Can we say RAPID wear? Cheers What exposed bearings? They are sealed ceramic bearings. But again, the frame must be custom built for it. So there's no way it would ever make it on the market. Custom Frame? You mean like a MTB with fore and aft suspension? That will never make it on the market? -- cheers, John B. |
#23
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Tomorrow's Bicycle Drive?
On 7/6/19 9:26 am, John B. wrote:
On Thu, 6 Jun 2019 14:01:28 -0000 (UTC), news18 wrote: On Sun, 02 Jun 2019 16:48:57 +0700, John B. Slocomb wrote: See https://www.youtube.com/watch?v=-9gQ1KRhesM In the narration he mentions that a 24 speed gear set, or even more, would be perfectly feasible. No wires, no cables, either. Just a rehash of old ideas. The same reasons for the failure of shaft drives will see it fail again. Of couses, as ther is electronics involved, that will introduce another pile of reasons for it to fail. Why did shaft drives fail? Complexities? I *think*, generally heavier and less efficient than a chain. Of course they could be made robust enough to be reliable, but that generally adds weight. -- JS |
#24
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Tomorrow's Bicycle Drive?
On Fri, 7 Jun 2019 11:26:25 +1000, James
wrote: On 7/6/19 9:26 am, John B. wrote: On Thu, 6 Jun 2019 14:01:28 -0000 (UTC), news18 wrote: On Sun, 02 Jun 2019 16:48:57 +0700, John B. Slocomb wrote: See https://www.youtube.com/watch?v=-9gQ1KRhesM In the narration he mentions that a 24 speed gear set, or even more, would be perfectly feasible. No wires, no cables, either. Just a rehash of old ideas. The same reasons for the failure of shaft drives will see it fail again. Of couses, as ther is electronics involved, that will introduce another pile of reasons for it to fail. Why did shaft drives fail? Complexities? I *think*, generally heavier and less efficient than a chain. Of course they could be made robust enough to be reliable, but that generally adds weight. I've only looked at one shaft drive bike, and just looking at it I didn't think that the gears or the shaft looked especially fragile given the amount of power that they would have to transmit . After all we are talking about a half horsepower power plant, or less :-) But a chain drive may be in the 98% efficiency range and I doubt that two 90 degree gear drives would be as efficient and probably cost more too. -- cheers, John B. |
#25
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Tomorrow's Bicycle Drive?
On 6/6/2019 9:26 PM, James wrote:
On 7/6/19 9:26 am, John B. wrote: On Thu, 6 Jun 2019 14:01:28 -0000 (UTC), news18 wrote: On Sun, 02 Jun 2019 16:48:57 +0700, John B. Slocomb wrote: See https://www.youtube.com/watch?v=-9gQ1KRhesM In the narration he mentions that a 24 speed gear set, or even more, would be perfectly feasible. No wires, no cables, either. Just a rehash of old ideas. The same reasons for the failure of shaft drives will see it fail again. Of couses, as ther is electronics involved, that will introduce another pile of reasons for it to fail. Why did shaft drives fail? Complexities? I *think*, generally heavier and less efficient than a chain.Â* Of course they could be made robust enough to be reliable, but that generally adds weight. I think shaft drives are heavier, less efficient, far more expensive, and much more limited in gearing. The early shaft drive bikes were all fixed gear, AFAIK. To run smoothly and efficiently, gears need much more precision than chains or belts. In particular, the distance between mating gears has to be precisely controlled. In the case of bevel gears, that means very rigid supports in a couple different directions. And if you want even ten different gear ratios with a shaft drive? That means another box full of gears, probably in the rear hub. Pretty soon price and weight are soaring. Oh, and unlike derailleur gears, you don't get to change your gear ratios to suit. You're stuck with whatever they built into the gear box. -- - Frank Krygowski |
#26
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Tomorrow's Bicycle Drive?
On 6/6/2019 7:28 PM, John B. wrote:
On Thu, 6 Jun 2019 09:11:13 -0700 (PDT), Sir Ridesalot wrote: On Sunday, June 2, 2019 at 5:49:03 AM UTC-4, John B. Slocomb wrote: See https://www.youtube.com/watch?v=-9gQ1KRhesM In the narration he mentions that a 24 speed gear set, or even more, would be perfectly feasible. No wires, no cables, either. -- Cheers, John B. I can just imaging what road grit when it rains will do to those exposed bearings and interface. Can we say RAPID wear? Cheers Probably about the same as those exposed chains and sprockets when it rains and they get all muddy :-) As we know, sprockets and chains do wear, largely because of the exposure to road grit. But chains are cheap commodity items spit out of machines at a rate of thousands of miles per day. Sprockets are essentially flat stampings, now with some minor ground-in contours. Nothing necessarily expensive there. The thought experiment that's being proposed would require lots of complex 3-d machining. It's not going to be cheap to replace worn bits. But no worries. It's never coming to market. -- - Frank Krygowski |
#27
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Tomorrow's Bicycle Drive?
On Fri, 07 Jun 2019 06:26:59 +0700, John B. wrote:
On Thu, 6 Jun 2019 14:01:28 -0000 (UTC), news18 wrote: On Sun, 02 Jun 2019 16:48:57 +0700, John B. Slocomb wrote: See https://www.youtube.com/watch?v=-9gQ1KRhesM In the narration he mentions that a 24 speed gear set, or even more, would be perfectly feasible. No wires, no cables, either. Just a rehash of old ideas. The same reasons for the failure of shaft drives will see it fail again. Of couses, as ther is electronics involved, that will introduce another pile of reasons for it to fail. Why did shaft drives fail? Solp and flex were one. Road crap is another. Hard to maintain. I can not wait to see that drive train after a days mtn biking on wet, rainy days. Complexities? And so we have hydraulic brake systems as opposed to simply mechanical brakes, electronic shifters as opposed to simple mechanical systems, and so on. Yep, all extra points of unreliability. The real relaibility test is, can I ride it home when stuff fails. |
#28
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Tomorrow's Bicycle Drive?
On Fri, 7 Jun 2019 04:03:01 -0000 (UTC), news18
wrote: On Fri, 07 Jun 2019 06:26:59 +0700, John B. wrote: On Thu, 6 Jun 2019 14:01:28 -0000 (UTC), news18 wrote: On Sun, 02 Jun 2019 16:48:57 +0700, John B. Slocomb wrote: See https://www.youtube.com/watch?v=-9gQ1KRhesM In the narration he mentions that a 24 speed gear set, or even more, would be perfectly feasible. No wires, no cables, either. Just a rehash of old ideas. The same reasons for the failure of shaft drives will see it fail again. Of couses, as ther is electronics involved, that will introduce another pile of reasons for it to fail. Why did shaft drives fail? Solp and flex were one. Road crap is another. Hard to maintain. I can not wait to see that drive train after a days mtn biking on wet, rainy days. Complexities? And so we have hydraulic brake systems as opposed to simply mechanical brakes, electronic shifters as opposed to simple mechanical systems, and so on. Yep, all extra points of unreliability. The real relaibility test is, can I ride it home when stuff fails. You mean like when the chain breaks or a wheel "tacos"? http://tacocleanse.com/one-taco-you-...-bicycle-taco/ -- cheers, John B. |
#29
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Tomorrow's Bicycle Drive?
John B. wrote:
On Fri, 7 Jun 2019 11:26:25 +1000, James wrote: On 7/6/19 9:26 am, John B. wrote: On Thu, 6 Jun 2019 14:01:28 -0000 (UTC), news18 wrote: On Sun, 02 Jun 2019 16:48:57 +0700, John B. Slocomb wrote: See https://www.youtube.com/watch?v=-9gQ1KRhesM In the narration he mentions that a 24 speed gear set, or even more, would be perfectly feasible. No wires, no cables, either. Just a rehash of old ideas. The same reasons for the failure of shaft drives will see it fail again. Of couses, as ther is electronics involved, that will introduce another pile of reasons for it to fail. Why did shaft drives fail? Complexities? I *think*, generally heavier and less efficient than a chain. Of course they could be made robust enough to be reliable, but that generally adds weight. I've only looked at one shaft drive bike, and just looking at it I didn't think that the gears or the shaft looked especially fragile given the amount of power that they would have to transmit . After all we are talking about a half horsepower power plant, or less :-) But a chain drive may be in the 98% efficiency range and I doubt that two 90 degree gear drives would be as efficient and probably cost more too. -- cheers, John B. It may only be a half a horsepower, but 100 ft-lbs of torque is easily attainable at the crank. |
#30
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Tomorrow's Bicycle Drive?
On Fri, 7 Jun 2019 05:52:31 +0000 (UTC), Ralph Barone
wrote: John B. wrote: On Fri, 7 Jun 2019 11:26:25 +1000, James wrote: On 7/6/19 9:26 am, John B. wrote: On Thu, 6 Jun 2019 14:01:28 -0000 (UTC), news18 wrote: On Sun, 02 Jun 2019 16:48:57 +0700, John B. Slocomb wrote: See https://www.youtube.com/watch?v=-9gQ1KRhesM In the narration he mentions that a 24 speed gear set, or even more, would be perfectly feasible. No wires, no cables, either. Just a rehash of old ideas. The same reasons for the failure of shaft drives will see it fail again. Of couses, as ther is electronics involved, that will introduce another pile of reasons for it to fail. Why did shaft drives fail? Complexities? I *think*, generally heavier and less efficient than a chain. Of course they could be made robust enough to be reliable, but that generally adds weight. I've only looked at one shaft drive bike, and just looking at it I didn't think that the gears or the shaft looked especially fragile given the amount of power that they would have to transmit . After all we are talking about a half horsepower power plant, or less :-) But a chain drive may be in the 98% efficiency range and I doubt that two 90 degree gear drives would be as efficient and probably cost more too. -- cheers, John B. It may only be a half a horsepower, but 100 ft-lbs of torque is easily attainable at the crank. But, I can apply 100 ft-lbs of torque with my little finger :-) In fact the average US male, who weighs 197.6 lbs, can exert a force of 110.16 ft-lbs, using a 170mm crank arm, simply by standing on the pedal. https://www.medicalnewstoday.com/articles/320917.php -- cheers, John B. |
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