MAFAC Brake Adjustment Notes
Hi Jim,I don't know if this is what you are talking about. I saved it from the iBOB list a while back.
Doug
Date: Thu, 28 Jan 1999 09:07:09 0800
From: Hahn Rossman <hahn@aa.net>
Subject: Re: [BOB] Technical questions
Patrick and/or Judy Moore wrote:
> One: The Mafac centerpulls on my Fuji have a straddle cable that is
> thinner than most brake wire; almost as thin as derailleur cable. Given
> that these brakes must be years old, ought I to change them? I see no rust
> or wear on them.
These are *really* hard to find as replacement parts and the usual fix is to use a derailleur cable. If they aren't frayed I wouldn't worry about it.
> Two: I know this has been discussed before, but refresh my memory: how does
> one get rid of squealing on Mafac centerpulls besides replacing them?
This is much easier to show than explain, but here goes... You need to toe the brakes in as usual but you also need to make the same sort of compensating for the fore to aft deflection, that is raise the back of the brake pad compared to the front. I know this sounds wierd, but if you watch the brake flex as you use it(a somewhat scary event) you will see why this is a good idea. Having said all that, the mafacs are some of my favorite brakes; they have great gobs of reach, they stop well when set up right, and they are usually free. You can also vary the leverage(and thereby the feel) of these brakes by changing the length/angle of the straddle wire.
> Three: I got a 5 speed fw on an old Shimano road hub with an axle spaced to
> 126 OL without any dish in the wheel; I think there even may be room for a
> six. If I went to 130 or 135 spacing, could I make a 7 speed Ultegra hub
> into a dishless wheel? What about an older (7 sp) XT hub?
>
> Four: For a total load plus rider weight of 200 lbs, which is better
> (assuming a dishless wheel in the back): 32 spoke 700C wheels with 14 g
> spokes, or 36 15 or 14/16 butted spokes? Or does it matter?
Jobst Brandt argues quite convincingly that 14-15-14 spokes are in fact stronger or at least more durable than plain gauge spokes, and I believe him. I think plain gauge spokes have two advantages, they are easier to build, and they are less expensive. However if your wheel builder is
competent and you can afford the extra $ the swaged spokes are better. I would strongly advise against the ultra swaged spokes though. By these I mean the DT revolution and Ritchey spokes. They have 17 or 18 gauge middle sections which have almost no torsional stiffness at all and
twist if you even look in their direction, and to paraphrase Jobst again it may not be possible to ever get enough tension on them due to the amount the middle stretches.
Hahn
At 04:23 PM 6/19/00 -0700, you wrote:
iBOBs,
I can't for the life of me remember -where-, but seem to recall reading
online an article about adjusting Mafac Racer brakes (well, centerpulls in
general). I -thought- it was at Sheldon's site, but cannot find it. Any
ideas?
thanks,
-JimG
"I always sneeze in threez."
