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From: AMuzi <am@yellowjersey.org>
Newsgroups: rec.bicycles.tech
Subject: Re: RE: Re: Petential Energy doing Work
Date: Sun, 30 Jun 2024 15:39:40 -0500
Organization: Yellow Jersey, Ltd.
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On 6/30/2024 2:54 PM, Tom Kunich wrote:
> On Sun Jun 30 07:38:55 2024 John B.  wrote:
>> On Sat, 29 Jun 2024 23:26:05 GMT, Tom Kunich <cyclintom@yahoo.com>
>> wrote:
>>
>>> On Sat Jun 29 15:45:47 2024 Frank Krygowski  wrote:
>>>> On 6/29/2024 3:06 PM, Tom Kunich wrote:
>>>>> On Fri Jun 28 21:59:35 2024 Frank Krygowski  wrote:
>>>>>> On 6/28/2024 8:05 PM, Tom Kunich wrote:
>>>>>>> On Fri Jun 28 16:16:09 2024 Frank Krygowski  wrote:
>>>>>>>> On 6/28/2024 2:22 PM, Tom Kunich wrote:
>>>>>>>>> Using Pogacar as an example let's say that normal upright riding puts his CG 1.5 meters abovr the ground. Simple Triganometry will tell us that the CG at 45 degrees lean is .707 that of his uptight position. (I have seen him lean more thn 45 degrees.) This makes a change in potential energy of 1.5 m x 0.707 = 1.06 m. Or about a change in CG of 0.44 meters.
>>>>>>>>>
>>>>>>>>> As an estimation, Pogacar and bike weigh 166 lbs or 75 kg. The change in potential energy from upright to a 45 degree lean for a corner is 1100 joules upright and 780 leaned over or a change in energy in the bike structure of 320 joules, or if you prefer, watts. In a frictionless world this would cause the bicycle to accelerate as it leaned. But this is not a frictionless world and what happens is that much of this 320 watts is pushed into the tires and absorbed by the friction in the tires resisting the centrifugal force and holding the tires to the ground.
>>>>>>>>>
>>>>>>>>> The physics are clear and well understood even though there seems to be quite a bit of misunderstanding on the group. Andrew thinks that the change has something to do with the CG to the tire's contact patch. That is not the change in energy but the direction of the force resisting the cenptrifugal forces.
>>>>>>>>>
>>>>>>>>> Since a rather hefty 320 watts are added to the energy simply by lowering the CG in a gravity field you can more understand why a bike in a turn may seem to slide out from under a rider so rapidly. Once the tires break traction there is no counter action against the increased energy. This should also give you a much greater appreciation of just how much traction to spare the sides of the best tires have over the use of it while upright and not braking.
>>>>>>>>>
>>>>>>>>> Now to be correct we have to remember that in order to be able to corner at 45 degrees, you have to be going at such a speed that on flat ground you would be pouring 700 or 800 watts into the pedals and so the addition at this speed is some 40% of a small number since very little energy is absorbed into the tires if you are not accelerating or braking. But the tires absorb is all resisting the centrifugal forces. Under normal contitions the upright bike's tires only absorb a significant amount of energy while accelerating or braking. And pro-level riders can and do commonly apply 1400 or more watts into acceleration.
>>>>>>>>>
>>>>>>>>> And since you are forced to stop pedalling at that angle of lean, the 700 or 800 watts are reduced to the 320 which are added through the change in potential energy.
>>>>>>>>>
>>>>>>>>> Have fun thinking about that.
>>>>>>>>
>>>>>>>> That's absolute nonsense.
>>>>>>>>
>>>>>>>> Try coasting at a fairly high speed on a flat, smooth surface, maybe a
>>>>>>>> parking lot. Watch your speedometer as you lean into a sharp curve. You
>>>>>>>> don't increase in speed while in the curve due to any loss in potential
>>>>>>>> energy.
>>>>>>>>
>>>>>>>> Watch your speedometer again as you exit that curve and go straight. You
>>>>>>>> will not find a significant decrease in speed. That indicates that it's
>>>>>>>> wrong to think the tires were "absorbing" the change in potential energy.
>>>>>>>>
>>>>>>>> And anyone who thinks Joules are the same as Watts ("320 joules, or if
>>>>>>>> you prefer, watts") knows very, very little about physics.
>>>>>>>>
>>>>>>>> -- 
>>>>>>>> - Frank Krygowski
>>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> It's nice to know that you cannot understand English but then I didn't expect you to know anything about bicycles since you're still stuck in the era with wheels with loose balls and high friction and downtube shifters with a 7 speed freewheel.
>>>>>>
>>>>>> That's kind of funny! You're wrong on all three counts!
>>>>>>
>>>>>> But your overall point is classic Kunich: You made a fool of yourself
>>>>>> talking about physics, so you try to insult someone else's bikes.
>>>>>>
>>>>>> -- 
>>>>>> - Frank Krygowski
>>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> It isn't surprising that you cannot understand the simple physics whish even has the potential energy gains or loses calculators all over the internet from almost every college. But you as a helpless ass don't even bother to look it up and tell us all we're wrong because your own education is lacking.
>>>>
>>>> :-) My degrees in engineering are lacking? Even my high school education
>>>> is lacking? Says a guy who has none of that education?  That's funny!
>>>>
>>>> Come on, Tom, do a demonstration. Have your wife film you standing tall
>>>> while track standing, then magically zooming off without pedaling by
>>>> sitting down on the saddle. You know, so your potential energy converts
>>>> to kinetic energy!
>>>>
>>>> BTW, there was for a brief time a bicycle that put such an effect to
>>>> use. The Ingo-bike had no pedals, and was more like a scooter than a
>>>> bicycle. Its eccentric wheel enabled it to be propelled - rather
>>>> inefficiently - by bounding up and down in sync with the wheel rotation.
>>>> See https://en.wikipedia.org/wiki/Eccentric-hub_scooter
>>>>
>>>> or videos like https://youtu.be/EHlWS-dYvqE?t=13
>>>>
>>>> I rode one very briefly at a museum.
>>>>
>>>> -- 
>>>> - Frank Krygowski
>>>>
>>>
>>>
>>>
>>>
>>> Thank God that I didn't have an education like you. I could be living off of the income of a college which is on the verge of collapse (Youngstown is spending $17 million a year which represents the attendance of more than 400 students completing a 4 year degree) instead of having investments worth 1.2 million now and accomplished something with my life instead of pretending.
>>
>>
>> Doing something with my life... Hmm.
>> Claims to have millions but lives in a cheap house in what he
>> describes as a slum... drives an old "clapped out car" and fixes old
>> junk bicycles primarily by asking Mr. Andrew "WHAT DO I DO".
> 
> John, you really should talk about the things you know. My "cheap house by your reconning is worth $920,000 at the latest claim by a conpany that flips houses and has made me an offer. What is your house worth? 100 baht?
> 
> Since you haven't ridden bicycles in two decades, and when you did they were Thai bikes with cheap components and made out of cheap steel at what time did you learn to judge the worth of a bicycle? And perhaps you can quote me asking "WHAT DO I DO?"
> 
> Andrew, unlike you is an expert and the rare occasion in which I have a problen I believe in putting questions to experts and not pretending that I know everything.
> 
> That appears to me like you're suggesting that you're an expert at something. Perhaps you could tell me what you're an expert in? Living in the only country in which your Master Sargeant's retirement from the service can allow you to live as one of the middle class?
> 
> 

Well, thank you; I think I may have something to offer on 
the subject of bicycles.

Regarding 'cheap steel', my 1953 Raleigh certainly 
qualifies, being thick seamed 1020. It's heavier than your 
bicycles, and yours are stronger in many ways as well. That 
said, it's a joy to ride. Excellent handling and 
comfortable, I have come to love it dearly over the past 53 
years of riding it. You might allow some Thais the same 
grace regarding their bicycles.
-- 
Andrew Muzi
am@yellowjersey.org
Open every day since 1 April, 1971