Re: [CR]Mafac two cable brake lever question

(Example: Framebuilding:Norris Lockley)

From: "ternst" <ternst1@cox.net>
To: <sachshm@cox.net>
References: <44D14C8D.3030909@cox.net> <44D1525E.5050506@optonline.net> <000f01c6b6aa$886e1890$0200a8c0@D8XCLL51> <44D27C02.8070009@cox.net>
Subject: Re: [CR]Mafac two cable brake lever question
Date: Thu, 3 Aug 2006 18:27:14 -0700
reply-type=response
cc: g.duke@civenv.unimelb.edu.au
cc: classicrendezvous@bikelist.org
cc: g.duke@civenv.unimelb.edu.au

We still agree, hopefully I didn't intimate that tandems flip over forward easily. That pleasure is overwhelmingly reserved for singles. The point I'm trying to make is that the rear has to drag down first to ease handling and balance. With weight coming forward and too much front wheel brake pressure the back wheel can get "lighter" and maybe wash around, or the front wheel locks or twists, and /or collapses. OUCH! When two people start to feel out of balance and correct against each other then all control is gone. Think of when even under control if you lean into the turn and the rider in back leans out because of fear of falling all control hell breaks loose as you fight to keep your line. Magnify that when the tandem gets unstable and lookout! I've had on a 4 brake tandem both front brakes on one lever and both rears on another. So all teams have to figure out how they ride together to maximize safety and comfort for riding pleasure. This is hardly off topic as in my estimation learning how to ride is as important as correct parts, on our older machines. Perhaps even MORE important because we're dealing with out of production equipment that doesn't always handle as good as the modern stuff does. So riding correctly, adding to longevity of riders and bikes, being safe is on the money for this format. How you get there to achieve your comfort level is not as important as getting there. All these bikes handle differently and what ever you do to ensure safety and pleasure is correct. We ride differently and need different set-ups to achieve that goal. That's all that counts. The main thing is it works!


----- Original Message -----
From: Harvey M Sachs
To: ternst
Cc: Joseph Bender-Zanoni


<g.duke@civenv.unimelb.edu.au>; <classicrendezvous@bikelist.org> Sent: Thursday, August 03, 2006 3:43 PM Subject: Re: [CR]Mafac two cable brake lever question


> Well, Ted, I certainly respect your experience and views, but I'd point
> out some shades of difference of opinion, probably because the dynamics of
> tandems just aren't like those of singles.
>
> The critical point is that tandems with two riders just don't flip over
> with the front wheel as pivot. Too much weight too far back. You may
> have seen or heard about some couple flipping over; I have not. Of
> course, sliding the front wheel isn't a good idea, either, but in practice
> I've often controlled speed with the front brake only on the tandems we've
> owned. Again, I just would emphasize my dislike for operating any two
> brakes with the same lever. On a desirability scale from 1 - 10, I'd put
> it at about minus 1.
>
> harvey sachs
> mcLean va.
> (end of my comments on this topic, since it threatens to veer off topic,
> if not sliding out from under me)
>
> ternst wrote:
>
>> Here's my take: Our old tandem Mary and I rode around on was a Campy
>> equiped Gitane 531 frameset with Clement Strada 66 sew-ups.
>> We rode it for pleasure and not loaded touring.
>> Brakes were Campy Record.Our combined weight was about 270 US pounds.
>> Going about 40 plus on downhills and slower speeds on the flat never gave
>> us a stopping problem with this normal set up.
>> I have set up, repaired, fixed, and fit a lot of couples on their
>> tandems.
>> Whether SINGLE or TANDEM, I would NEVER set the front brake to actuate
>> before the rear when both brakes were on one handle! PERIOD!
>> Your thoughts are nice but your logic is flawed.
>> This is a prime example of counter intuitive mechanical execution.
>> The object of the braking system is to stop without losing control.
>> The front brake stops radically faster than the rear because of weight
>> distribution, cable length, housing compression, etc.
>> Ergo Bibamus. whoops, wrong salon.
>> Ergo: Apply the REAR brake just enough sooner to counteract the front
>> lunge, keep you on the saddle better and prevent wheel / bike sliding
>> possibility by the "drag" action of the rear brake.
>> Many of the tandem riders had to figure out how the steerer and stoker
>> psyche / mentalities complimented each other and arranged the brakes
>> accordingly.
>> Domestic tranquillity sometimes comes with compromising a little.
>> Some couples had two brakes some three and others four.
>> Double caliper, disc, drum or combos with any lever combo, take your pick
>> whatever worked best for the couple so they became a duo and not a duel.
>> Communication was the key.
>> Some of the couples had shift and or brake levers on rear and or front
>> and worked it out.
>> Most couples agreed that riding the brakes all the way downhill was not
>> good, harder slow down , keep speed where it was wanted, let bike roll,
>> apply brakes, and make it easier on hands and equipment.
>> Think about it, on a fixed gear, the front brake only will flip you over
>> if applied too abruptly. So you slide your butt back some and backpedal
>> to keep you balanced.
>> Nez Pas?
>> It's the same on a tandem. The weight on the back holds the bike a little
>> more stable but two riders sliding forward is a negative desired force.
>> so the REAR brake has to brake just a little sooner to maintain better
>> integrity.
>> That's my humble opinion.
>> Ted Ernst
>> Palos Verdes Estates
>> CA USA
>>
>> ----- Original Message -----
>> From: "Joseph Bender-Zanoni" <joebz@optonline.net>
>> To: <sachshm@cox.net>
>> Cc: <fred_rednor@yahoo.com>; <g.duke@civenv.unimelb.edu.au>;
>> <classicrendezvous@bikelist.org>
>> Sent: Wednesday, August 02, 2006 6:33 PM
>> Subject: Re: [CR]Mafac two cable brake lever question
>>
>>
>>> In some contradiction of Harvey, I think it is a good idea to be able to
>>> operate both rear brakes at the same time. Having a drum or disk brake
>>> as a drag brake, to take the heat load on long decents is a good idea if
>>> you ride in any kind of mountains. That being said, I have yet to
>>> implement it. I am thinking of a goofy looking stem shifter as I
>>> already have barcons. I went out on the tandem with my wife two weeks
>>> ago and the two cable front/rear Mafac lever, even though perfectly set
>>> up, just requires too much hand pressure. That's with a Pederson front
>>> and Mathhauser shoes on Mafac cantilevers so I don't know the next
>>> upgrade except my hands.
>>>
>>> Joe Bender-Zanoni
>>> Great Notch, NJ
>>>
>>>
>>> Harvey M Sachs wrote:
>>>
>>>> With all due respect, I've only seen one application where controlling
>>>> two brakes with one lever seemed appropriate. The rider of that bike
>>>> was one-handed.
>>>>
>>>> IMHO, in all other cases there are just too many compromises to be
>>>> made. 1) One lever controlling both rim brakes. Obviously impossible
>>>> to modulate relative force for better control on long grades, curves
>>>> and turns, etc. Since front brake is able to do more speed reduction,
>>>> want it to contact first and exert more force. But, if so set up, will
>>>> wear its pads more quickly, so vigilant and frequent maintenance is
>>>> required. 2) (mostly tandems) One lever controlling front rim brake,
>>>> dual-cable lever controlling both rim brakes. In general, leverage
>>>> (cable take-up) varies between rim brakes and hub brakes, so one or the
>>>> other will do next-to-nill work if actuated by same lever with same
>>>> travel for both.
>>>> If everything is working as you imagined it would, you can get into
>>>> real trouble. One day in Corvallis Oregon on a friends Jack Taylor
>>>> tandem, I got in trouble wrt oncoming car in a right turn situation.
>>>> So, I hit all the brakes (two cantis on dual lever, drum on the other).
>>>> Predictable result in a turn: rear wheel, "benefitting" from two brakes
>>>> and light load, locked up, so rear could slide nicely toward the car.
>>>>
>>>> Our preferred solution is pretty simple: rim brakes separately
>>>> operated by conventional single-wire road levers. Auxiliary (hub)
>>>> brake operated by tourist lever mounted very low on right bar. This
>>>> makes it impossible to operate both rear brakes at the same time, but
>>>> get excellent modulation of rear hub brake by using it while riding on
>>>> the drops.
>>>>
>>>> So, that's personal preference and reasons, I promise not to be a nanny
>>>> if your views differ.
>>>>
>>>> harvey sachs
>>>> mcLean va
>>>>
>>>> Geoff,
>>>> The twin-cable MAFAC levers on my tandem are exactly the
>>>> same shape as an ordinary, single cable lever. So you really
>>>> can only mount them on the "hook" of the handlebar. I suppose
>>>> you could try modifying the actual lever portion of the piece,
>>>> but in that case, I wonder if you would get sufficient leverage
>>>> to properly operate the brakes.
>>>> Best of luck with the project,
>>>> Fred Rednor - Arlington, VA (USA)
>>>>
>>>> --- geoff duke <g.duke@civenv.unimelb.edu.au> wrote:
>>>>
>>>>
>>>>>> I am wondering if anyone can tell me if a Mafac twin cable
>>>>>> tandem brake lever would work if it were placed on the top of the
>>>>>> handlebars.Like a cyclocross lever.Would it be able to work
>>>>>> on the flat section of bar or do they need to be on the bends like
>>>>>> other levers.Thinking about setting up a single speed bike with
>>>>>> canti's front and rear with one lever and considering that there
>>>>>> would be a good place for it.Sorry if this question is a bit clunky
>>>>>> but
>>>>>> hoping for an answer,
>>>>>> Geoff Duke Melbourne Australia