Re: [CR] who has trouble stopping with vintage sidepulls?

(Example: Framebuilders:Masi)

From: "Rudy Norvelle" <rudy43norvelle@comcast.net>
To: <classicrendezvous@bikelist.org>
References: <mailman.2460.1232668132.55131.classicrendezvous@bikelist.org> <44BA784B-5C5A-42E7-B54A-1E6172C64D16@earthlink.net>
Date: Fri, 23 Jan 2009 11:21:44 -0800
Subject: Re: [CR] who has trouble stopping with vintage sidepulls?


I bought my Cinelli in 1966 before Campagnolo brakes came out and had Weinmann levers with Mafac Top 63 calipers and still have them on the bike. The squeek though and always have.

Rudy Norvelle
In rainy
San Jose, CA
USA


----- Original Message -----
From: Jon Spangler
To: classicrendezvous@bikelist.org
Sent: Friday, January 23, 2009 11:07 AM
Subject: Re: [CR] who has trouble stopping with vintage sidepulls?



> 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
> Linda Hudson Writing
> 510-864-0370/FAX 864-2144
> MOBILE 510-846-5356
> hudsonspangler@earthlink.net