Re: [CR]Centerpull Calipers

> 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
>
> ----- Original Message -----
> From: <joebz@optonline.net>
> Subject: Re: [CR]Centerpull Calipers
>
>
> > CLB made a very fancy and innovative high end set of centerpulls.
> The
> > pivots are angled so the brakes are self energizing. The center
> "cable"
> > is a solid wire integrated with the springs. I have a set but I
> haven't
> > used them yet. Rare and hard to find.
> >
> > I think that you will find that the Campagnolo Delta, Wienmann,
> Modolo
> > aero type are poorly suited for a sports tourer in term of length
> and
> > clearance, give poor performance and are a headache to set up.
> >
> > I would also consider an ordinary set of Wienmanns or Mafacs with
> good
> > shoes. Mafac Tigers baby- now why the heck did they stop making
> that
> > brake with beefier calipers and fancy shoe adjustability?
> >
> > Joe Bender-Zanoni
> > Great Notch, NJ
> >
>
> _______________________________________________
> The Cliff Notes is that one persons grabby brake is another's failure to modulate a capable brake.

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 have a problem with the notion of "grabby" (ie. powerful) brakes being a problem in general. I guess I will be hard nosed and say that getting pitched over the front of the bike is the result of a lack of technique in controlling your CG, allowing your weight to pitch forward and incorrectly modulating the brakes. I will admit that that I have taken a sideways fall due to a front wheel skid caused by cantilever brakes, Mathauser pads, wet Fall leaves and a steep turn. Once only, and I was just going too fast for the conditions. I'd rather have a powerful brake to modulate and make the error than run out of braking power.

I remember Consumer Reports in 1972 saying that some bike had too much propensity to pitch people over the front and we all had a good laugh at the shop.

I don't buy the argument for a self-deenergizing design "provided the necessary leverage was present" for bicycles. In actuality, a first element for the performance of any braking system is getting the necessary leverage present. Almost all brake systems are self de-energizing under hard use. During hard braking the shoes start to melt on bikes or just fade on more sophisticated brakes that get beyond melting brake shoes. De-energizing brakes is a tricky deal and I don't see a need for anti-lock brakes on bicycles (let alone retrofits on classics).

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.

Joe Bender-Zanoni
Great Notch, NJ