Steve and all,
Apparently, many European pro racers combined Campi levers with Mafac calipers after Mafac centerpulls came out. I suspect that their use of Campi levers with the Mafac calipers was sponsorship-related, but the combo must have worked OK.
Has anyone else out there duplicated this, or used other hybrid lever- caliper combinations that they have found successful and effective?
Thanks,
Jon Spangler back in Alameda, California USA
On Jan 22, 2009, at 3:48 PM, <classicrendezvous-request@bikelist.org>
<classicrendezvous-request@bikelist.org> wrote:
>
> Message: 6
> Date: Thu, 22 Jan 2009 13:27:50 -0800
> From: Steve Maas <bikestuff@nonlintec.com>
> Subject: Re: [CR] Who has trouble stopping with vintage sidepulls?
> To: <classicrendezvous@bikelist.org>
> Message-ID: <4978E4D6.8090300@nonlintec.com>
> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed
>
> Thought I'd dive into this.
>
> Bicycle brakes are designed for a mechanical advantage of about 4
> to 5.
> That means moving one unit of distance between the pads requires about
> 4-5 units at the lever, the point where your hand touches it. If this
> number is much larger, you get a soft feel and the brakes tend to
> grab;
> much less, and they feel hard and it takes a lot of hand force to
> stop.
>
> I experimented with this some time ago, using road levers with
> cantilever brakes and vice versa. It was pretty scary. The "hard"
> brake
> required quite a bit of force to stop, in fact, my full strength; the
> "soft" one was so hard to control that I wouldn't leave the driveway
> with it.
>
> There is some room for adjustment of this effect in certain kinds of
> brakes. Especially cantilevers, and perhaps some center pulls, by
> adjusting the length of the straddle cable. All kinds of other things
> affect this as well, such as adjusting the pad position. But that's
> pretty minor.
>
> I suspect that our tendency to mix different kinds of levers and
> calipers (even unmatched sets from the same maker) has a strong effect
> on the kind of braking effects people are reporting. Other things that
> affect the hardness of the brakes' feel are the degree of toe-in at
> the
> pads, the amount of looseness in assembly--some looseness is necessary
> so they move at all--and the tendency of cable sheaths to squirm as
> longitudinal force is placed on them. (After all, there IS a reason
> why
> gear cable sheath is different!) Of course, it is possible that some
> calipers are so flimsy they're actually noticeably flexible (e.g.,
> modern department-store bikes).
>
> Furthermore, there are at least minor differences in the frictional
> coefficients and hardness of pad materials, especially if you include
> things like sintered metal pads in the evaluation. Of course, rims are
> part of the system too, and rim materials have an effect. Chromed-
> steel
> rims, for example, make most brakes "grabby" when dry and ineffective
> when wet.
>
> Steve Maas
> Long Beach, CA
>
>
> ------------------------------
Jon Spangler
Writer/Editor
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