Re: rear rim seems to rub

In article <ArudnakJd_XLndzanZ2dnUVZ_t3inZ2d@xxxxxxxxxxxxx>,
jim beam <spamvortex@xxxxxxxxxxxxxxx> wrote:
Luns Tee wrote:
In article <vaidncGliJ07zKHanZ2dnUVZ_tyknZ2d@xxxxxxxxxxxxx>,
jim beam <spamvortex@xxxxxxxxxxxxxxx> wrote:
Luns Tee wrote:
In article <GOCdnY7kbLrAMaTanZ2dnUVZ_jmdnZ2d@xxxxxxxxxxxxx>,
jim beam <spamvortex@xxxxxxxxxxxxxxx> wrote:
Luns Tee wrote:
In article <oZWdnS6ivZi-fKranZ2dnUVZ_jCdnZ2d@xxxxxxxxxxxxx>,
jim beam <spamvortex@xxxxxxxxxxxxxxx> wrote:
If the ratio of the caliper as a whole is 2:1 as you say, the
force being transmitted across the rim is 200N. How is 100N on the cable
side of the Y arm, vs. 200N on the pad side of the Y arm an equilibrium?
"floating" of the rim. just like in the avid mechanical disk brake caliper.
Floating only means that the supposed 200N from the C arm pad
is carried through to the Y arm pad, but the question is of how the Y
arm is able to press 200N against this - this is implicit in the
question I pose. Repeating part of the question is not an answer to
the question. You still have not addressed the question of how a 1:1
lever can have forces on it in a 2:1 ratio yet be in equilbrium.
no, reconsider the avid disk caliper i mention. one pad is completely
fixed, but braking force is applied equally from both pads because the
disk floats. rims do the same.
The one-side-fixed caliper is not a valid analogy: a 1:1 lever
between the pad and cable clamp is not a fixed stop. If the Y arm were a
fixed stop, then it would not rotate on its pivot, and we're left with a
single-pivot brake. What is under discussion is dual-pivot brakes.
but luns, with respect, if the y-arm is fixed, you have exactly the same
braking as with the avid disk brake.
IF the y-arm is fixed, then I agree with the avid brake as a
model. However, you yourself have claimed that the Y arm is free to
pivot, independently of the C arm at that.
it can be compressed independently of the c-arm.


What makes the Y arm, that
is otherwise free to pivot, into a fixed stop?
application of pressure from the brake cable.

That is NOT a fixed stop.

it is relative to the rim. hence equilibrium is established.

A freely pivoting 1:1 lever transmits
force from the pad through to force at the cable in a 1:1 ratio. So I
ask you one more time, with 100N of cable tension, if things are as
you say, how does 200N at the pads constitute an equilibrium?

see above. re-read the posts of myself and joe riel - repetition is
getting boring.

Yes, it is getting boring, however I repeat my question because
despite having been asked it over half a dozen times, you have yet
to give any sort of answer that is consistent with the fundamentals
of mechanics. A freely pivoting 1:1 lever has forces on its ends
in a 1:1 ratio, but you seem to believe that it can support a 2:1
ratio instead. If you actually had a consistent picture of how the
calipier works, you could tell us what forces each arm experiences,
and also show that these forces agree with the fundamentals of
mechanics. Instead, you just offer a non-statement using the word
'equilibrium' as though it were synonymous with 'abracadabra'.

So far as Joe Riel's posts, I don't see how anything he's said
supports your assertions at all, nor do I imagine he appreciates your
trying to claim that they do, but I will let him speak for himself.

Believe what you want - at this point, I believe it's clear
to everybody else that you do not present a consistent story with
your claim of a 2:1 caliper ratio, nor of the centering linkage being
uninvolved.

-Luns


.

Relevant Pages

  • Re: rear rim seems to rub
    ... jim beam wrote: ... force being transmitted across the rim is 200N. ... side of the Y arm, vs. 200N on the pad side of the Y arm an equilibrium? ...
    (rec.bicycles.tech)
  • Re: rear rim seems to rub
    ... jim beam wrote: ... side of the Y arm, vs. 200N on the pad side of the Y arm an equilibrium? ... braking as with the avid disk brake. ...
    (rec.bicycles.tech)
  • Re: rear rim seems to rub
    ... The cable does not pull at a right angle from the line from pivot ... What you measure here is the ratio for one arm of the caliper, ... ratio of cable tension to pad force is not 2:1 - you have to account ...
    (rec.bicycles.tech)
  • Re: rear rim seems to rub
    ... jim beam wrote: ... in a 1:1 ratio, but you seem to believe that it can support a 2:1 ... beam balance, and a 20kg weight on the other, the two are ... for in asking you how you think the Y arm can be in equilibrium. ...
    (rec.bicycles.tech)
  • Re: rear rim seems to rub
    ... there being nothing else acting on the arm ... after the cable and pad have been accounted for. ... Nobody has claimed anything about lowest ratio prevailing. ... However, if the contact point were at the center pivot, then the lower ...
    (rec.bicycles.tech)