Dans le message de
news:
[email protected],
[email protected] <
[email protected]> a réfléchi, et puis a déclaré :
> Regarding condescension - I can tell this dialog is decaying into
> that, as evidenced by your statement to dvt: "Golly, you have a
> strange way of using a keyboard to say nothing."
Read what was targeted, and you _should_ see the relevance. Has to do with
measurements, Mr. Engineer.
> But to let you know: Scientists, engineers and mathematicians can
> sometimes lose patience with people who are confident that their own
> lack of education is immaterial. Despite that, I'll try to be
> patient.
Your condescension is noted, with a wry smile, sonny. (Sorry to repeat
myself, little one.)
>> You are happy to accept that there is damping in lateral deflection
>> and not vertical ? Interesting. Amplitude, frequency, decay ?
>> Rationale ?
>
> Perhaps the problem is "ride" is poorly defined.
Mr Engineer needs writing assistance.
> Perhaps you are
> speaking of a different aspect of "ride" than most of us are.
Not in the least ! But I am paying attention to more than the isolated
issue you wish to beat to death. I really would like to know what you ride,
why you chose that, and what it's ride quality is.
> Personally, what I've been discussing is road vibration and road
> shock. Those phenomena occur almost entirely in the vertical plane.
I see - you don't ride.
> And yes, I do understand that amplitude, frequency and decay can be
> completely different in different directions. If you don't understand
> that, it's further evidence that you're not equipped to contribute
> meaningfully to this discussion.
Asking can be a contribution. Well, I asked, as you were not observing any
other aspect of "ride quality". I had to ask, to understand if you have
been on two wheels recently.
> Grab a flat ruler or meter stick. Clamp it horizontally to a table,
> letting its length protrude. Vibrate it vertically. Vibrate it
> horizontally, if you can. You'll see that behavior can be completely
> different in different directions.
What I may want to do with a ruler is my business. And I behave.
>> If you believe that lateral deflection bears not at all on ride
>> quality, please let the rest of the world know.
>
> The effect of lateral deflection on _vertical_ ride quality - that is,
> shock and vibration absorption - is negligible.
We are limited to being vertical all the time ? You sure about that ? You
ride curves that way ? Over 5 km/h ?
>> If you believe that all bicycles are
>> subject only to perfect vertical deflection for all the time they are
>> ridden, also please let us know.
>
> No, I've never said that. In fact, I've described lateral deflection
> in an Alan aluminum frame I rode. However, it's not pertinent to the
> problem at hand, which is vertical.
Chainstays or seatstays, or the uniforked versions of them, don't move ?
Have you thought about the torsion at the attachment point, where the
lateral flex occurs ? Is there no contribution to a vertical change ? Or
is it lateral like a fully compliant hinge ? And the seatstays ? the
bottom bracket. Is the answer that all that other stuff is "negligible"?
>> If you submit that there is *no*
>> deflection in the vertical plane, for any and all types of materials
>> used to construct modern bicycles, please state that clearly.
>
> Such a man of absolutes! I submit there is _negligible_ vertical
> deflection in the seatstays of a conventional bike, no matter what the
> material is. And I'm quite capable of calculating such deflections.
> For that matter, so are most of the students in our freshman-level
> courses.
We are talking about people measuring what they sense. When you hit a bump,
do you take out your (noted above) ruler first, to confirm that the
topography you just traversed has adequate variability to be categorized as
a bump, or are you happy with the "seat of the pants" (Oh, how much fun that
was !) recognition of the fact ?
>> The problem you face is that we folks who ride and do experience
>> differences in bicycles
>
> ?? As if the rest of us don't ride bicycles??
I am not really convinced that _you_ do.
>>are capable of measuring (sensing, with appropriate receptors
>> all over the place) a good number of things that your crowd simply
>> has not yet figured out how to quantify to make you comprehend.
> 
Ah yes. And the proof will come in the reports of blind tests
> that you will very soon provide. Correct? ;-)
Blind proves nothing, just as you attempt to state that negligible yet
measurable differences are phantom ones. Measurable and sensible. The
issue brought up, at the origin of this thread, was whether there are actual
differences in ride quality, and whether they are significant enough to
consider alternative rear triangle composition in the purchase of a bike.
Perhaps you forgot. Not just are they measureable (which I'll bet you will
give me). The opinion (not engineering fact) about the value of the
measurable difference is what was sought. It's fine if you want to say that
you think the measureable differences are not worth spending money, but to
effectively say that the materials exhibit no differences is the extreme
position I fairly criticize.
Please take you time to make me look like a buffoon, as I have tired of this
and plan to be out, riding, early. I won't say I'll miss our
counterpoint....
