RE: [CR][CR Was: Centerpulls; before: Cantilever Brakes Now: Dual p ivots


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From: themaaslands@comcast.net
To: Classicrendezvous@bikelist.org (Classic Rendezvous)
Subject: RE: [CR][CR Was: Centerpulls; before: Cantilever Brakes Now: Dual p ivots
Date: Sat, 03 Apr 2004 21:03:29 +0000

Janny Heiny (I am taking that is how you like to be addressed seeing as how you take the liberty to change the Campagnolo family name) writes:
> The beauty of the center-pull design (like cantilevers) is that you can
> increase reach without changing mechanical advantage.

This is not true as the longer arms below the pivot point flex more so you lose mechanical advantage. On the cable side of the pivot the mecahnical advantage does remain the same. (I must admit that I don't know where you want to go with this point, perhaps you can explain how this difers from sidepull brakes.)

As for Mafac being comparable to modern brakes, I respectfully disagree, as will anybody with an engineeering background. Mafac brakes simply do not have the measurable mechanical advantage of the newest generation of brakes. This is not an opinion, this is a mechanical fact that can be measured and not subject to personal fancy or preference. They are therefore to be compared to most pre-90's brakes. I agree that the Mafac calipers work better than most pre-90's brake calipers. As for any child being able to stop your Rivendell, you are obviously not using stock 1960's Mafac levers as no average pre-teen child could activate the levers while riding on the hoods and would have difficulty reaching them from the drops. The distance of Mafac levers from handlebars is notoriously long reach (just like the original Campagnolo, who however quickly learned and remedied with shorter reach levers). The curvature of the lever also requires longer finger/hand reach to activate from the hoods than Campagnolo, Modolo, Universal, Shimano, Dia-Compe... My gripes about Mafac brakesets are that until the mid-70's, the levers were simply not functional for all but those with larger hands, their very poor quality control (overly generous production tolerances led to all the brakes that squeal as the squeal is not inherent to the design) and their lack of a quick release mechanism in the case of broken spokes or such. Campagnolo NR/SR brakes, while far from perfect, do not suffer from any of these deficiencies. By siding with Mafac, you have determined that these deficiencies are not relevant to you. I would not have any qualms whatsoever to use Mafac calipers (and have done so on my own bikes), but apart from the most recent levers

--
Steven Maasland
Moorestown, NJ

> >A Universal mod.39 and mod.68 Super are more similar to one another

> >than is a 1950's Mafac being compared to a late 1970's Mafac.

>

> The only difference between a 1950s Racer and the last is the writing

> and the substitution of brass with plastic bushings. The first ones

> had a slightly different arm shape, but you have to look carefully to

> see the difference. They always had forged arms, and the geometry

> hasn't changed at all. But since I don't know much about Universals,

> it is well possible that the Universals were entirely unchanged, down

> to the patent number, over the years...

>

> >

> >I have a question about Mafac brakes: What are the differences

> >between the 'raid' model and the 'racer' model. Is the raid simply a

> >racer where the bolt-on attachment was simply removed?

>

> Longer reach on the Raid vs. the already long reach on the Racer. >

> >

> >Contrary to what has been said by others recently, I feel that

> >brakes are actually the components that have made perhaps the

> >greatest improvement to overall racing performance. New brakes,

> >including all of the accessory elements like brake pads, cable

> >housing, cables, lever hoods and rim treatments, have greatly

> >improved performance. Without these improvements, none of the old

> >school brakes worked terribly well. With large and strong enough

> >hands, and all these new accessory elements, I agree that you can

> >get old school brakes to brake virtually as well as modern ones, but

> >what is overseen in this is the amount of energy spent and all those

> >people with either small hands or not overly strong hands. Under

> >racing conditions or riding a fully loaded touring bike or tandem,

> >the energy spent braking becomes quite extreme and this is a readily

> >measurable quantity, anybody denying this is simply lying to

> >themselves. The same goes for brake modulation.

>

> I agree if you include the Mafacs as "modern" brakes. When I changed

> from Campy sidepulls to Mafacs on my main bike (before: Marinoni

> Columbus SL with Campy Victory, which in performance are identical to

> NR/SR, various pads including Campy, Dia-Compe, Matthauser, after the

> Rivendell with 1960s NOS Mafac Competitions brazed-on, Matthauser

> pads), I had to get used to braking with one finger instead of the

> full force of my hands. Same cables, older-style non-anodized rims on

> the Rivendell vs. modern Campy and Wolber on the Marinoni.

>

> Even a child with weak hands would have no problem getting the

> Rivendell to stop in no time. I once tried the Campy Delta brakes,

> but my hands weren't strong enough to get good stopping power out of

> them. (Maybe the mechanical advantage is adjustable on these, in

> which case it would be unfair to blame the brake.)

>

> Even set-up as they were originally (my 1965 Cinelli with Mafac Top

> 63 brakes has the original cables, housing, even pads!), the

> centerpulls y work great. Sometimes they may squeal, but they always

> modulate speed well. In fact, they even stop the bike.

>

> When racing with the above-mentioned Campys after the advent of dual

> pivot brakes, it was a bit disconcerting at times, when bikes in

> front of me "modulated speed" so much quicker than I was able to do.

> In fact, even the first-generation Ultegra sidepull brakes were far

> superior in speed modulation, as I noticed when I almost ran into

> Barbara several times. I no longer have this problem, as I use the

> Mafacs on most bikes now.

>

> However, in actual racing (vs. city riding), braking really isn't

> that important, so the inferior speed modulation power wasn't a big

> issue. I think that is what Campy (or maybe it was somebody else

> talking about Campy) was trying to say: In racing, you decrease your

> speed from 45 to 30 mph occasionally, to take a turn. On tight

> switchbacks, you might even decelerate to 25 mph... With the wind

> resistance on your side, that isn't a big task for your brakes. Any

> decent brake will do fine, especially as there are few descents used

> for races that are steeper than 10%. In my experience, the problem

> usually were timid racers who braked more than I anticipated, a

> problem professionals presumably don't face.

>

> Riding in the city, on a 12-14% hill with a stop sign at the bottom

> puts much higher demands on braking performance.

>

> "Braking only slows you down" a Cat. 1/Pro racer once told me as I

> was getting into cycling...

> --

> Jan Heine, Seattle

> Editor/Publisher

> Vintage Bicycle Quarterly

> http://www.mindspring.com/~heine/bikesite/bikesite/