[email protected] wrote:
> On Nov 9, 10:22 am, Tim McNamara <[email protected]> wrote:
>
>> [email protected] wrote:
>>
>>> On Nov 9, 12:47 am, jim beam <[email protected]> wrote:
>>>
>>>> for the skeptics.
>>>>
>>>> http://www.flickr.com/photos/38636024@N00/1928128941/
>>>>
>>>> http://www.flickr.com/photos/38636024@N00/1928128939/
>>>>
>>>> http://www.flickr.com/photos/38636024@N00/1928128923/
>>>>
>>> What about a picture from the side? If the pads aren't parallel
>>> to the mounting bolt, this proves absolutely nothing.
>>
>> It's difficult to tell from the photos, but it appears that there
>> is an eccentric motion to the pad on the right. As the brake
>> closes, the right pad not only moves towards the other pad but also
>> forward (down, in the photo). This could be explained by the
>> pivots not being parallel to each other.
>
> That's the great thing about orbital pad adjustment. You can make it
> look like all kinds of neat things are happening if you only took at
> the brake from one direction. Square the pads up like they would be
> on a bike (where some of us use our brakes) and the eccentricity
> goes away. It's interesting that jim isn't even trying to show a
> front brake doing the opposite.
Far be it from me to accept anything from "jim beam" at face value,
however I am not at all certain that the orientation of the pad would
produce the apparent effect shown in the photos. The apparent movement
is about 1/8". The sweep of the ends of the pads would be the same
regardless of their orientation.
The problem with the photo is that the brake is lying on an open book
rather than mounted firmly. If "jim beam" really wants to demonstrate
his point, he'd do better to mount the brake on a flat surface (e.g.,
drill a mounting hole through a board and mount the brake to it), which
would provide a plane reference surface against which to judge the
movement. I don't own a dual pivot brake or I'd do it myself.
Unfortunately, "jim beam" won't accept my suggestion simply because it
comes from me, so the point will remain moot.
If the eccentric motion is real, the likelier explanation is that the
pivot axes are not parallel.
(And what's up with Google Groups's removal of newlines from quoted
material? What a pain in the ass to have to keep fixing. That's 90%
of the legibility problem in these long threads. Google must fear the
whitespace. Jeez, I wish people would use real newsreaders.)