Joe Bender-Zanoni wrote:
>" I have a problem with this objection to powerful brakes as being pretty
>theoretical. In the first place I can't think of many situations that
>exagerate "grabbiness" in some sort of negative sense. Maybe glue or rosin
>on the rim."
I wasn't referring to overly powerful brakes here, but rather the increase in variability that comes with a self-energizing design. Thus, the variability in friction, often due to damp air (increasing friction) or rain (decreasing friction) is *exponentially* exaggerated by a self-energizing design. A self-de-energizing design, OTOH, decreases the net effect of these variables. It's much like the grab that a grinding wheel exerts (or not) on a metal part that's held at the wrong angle to the wheel surface. I don't have any problem with too much power as the lever force increases and the pads warm up, but the initial grab can be disconcerting and could be worse under the "right" conditions, like in a group, on a slick surface or with new (non-machined, of course) rims. Perhaps that's what CR encountered, as it did affect my bike for a good while when I added urethane pads and the Module-E rim sidewalls were still shiny. A worn-in rim surface is less grabby.
J B-Z:
> "I have used the Pedersen self energizing brakes on my tandem and liked
> them. I'll let people know what I think of the CLBs when I try them. I
> will say that I just thought of one factor that would significantly change
> the self-energizing brake equation. Add high friction shoes like
> Mathauser at your own risk because this will exagerate the servo feedback
> of the brake and the modulation may be trickier than expected. "
That's specifically what I was referring to, but at least with a tandem it's
much less noticeable up until the point where serious fade sets in. I don't
ride tandems, but I've heard one's hand can get tired and cables stretch
more, etc, especially with the older parts.
>
David Snyder
Auburn, CA USA
> ----- Original Message -----
> From: dddd <dddd@pacbell.net>
>> I am wary of any self-energizing brake design as they are doubly
>> affected by
>> water or any conditions such as humidity that can exaggerate
>> grabbiness.
>> I think an arguement could be made for a self-de-energizing design,
>> provided
>> the necessary leverage was present.
>>
>> A tendem is less affected by grabbiness because of the extra weight
>> and
>> wheelbase, hence their being a reasonable application for S.E. brakes.
>>
>> David Snyder