I can virtually induce squeal on demand on four of my bikes. All I need
to do is let my hands get a little dirty or greasy and then touch the
rims, or get a stray drop of T9 on the rim while lubricating the chain.
Two of those are centerpulls, one RAID and one Paul Racer; the other two
are cantilever, one classic long arm XT, the other Avid Shorty 4. The
field-expedient cure in all cases is to squirt some water on the pads
and the rims, and then ride for a bit with the brakes on hard. This
wipes the schmutz off the rims.
I've tried that on other people's bikes, too: stopped once to take a
break on the little bridge next to the Eisenhower farm up in Gettysburg
one time and along comes this guy on a rusty old touring bike, brakes
squealing like banshees loosed upon the world, and I stopped him and
said for God's sake let me try to quiet that heeeedious shrieking. A
couple of squirts, rode once down the length of the bridge, and blissful
peace and quiet. So it's not just mine that respond to this.
The comment re: precise location of the braze-on posts is a restatement
of something Jan said in a discussion of the Compass brakes, and why
there is no toe-in adjustment, to the effect that the builder should set
the location of the pad correctly by proper and perfect placement of the
posts while brazing them on. Can't recall where this was, probably on
the iBOB list but possibly here or in the blog, time frame certainly
within the past 30-45 days. Don't have time to hunt for it now.
If I had to do it again, I'd get brazed-on centerpulls on my MAP. That
wasn't on offer when I got it, although evidently a couple of people
that year pleaded and begged and talked Mitch into doing it for their
bikes; subsequently it became a standard feature. I'm not sure if I'd
have done it then had I known, because I had the canti brakes, take-offs
from my Saluki, along with the wheels and the entire drivetrain, and at
that moment I felt as though I had to put a cap on the cost of the
bike. Today, I'd just go for it and let the (financial) chips fall
where they may.
On 06/05/2016 12:45 PM, William deRosset wrote:
re: squeal on brazed-on centerpulls:
Dear Steve,
In my experience, it is related to the amount of slop in the pivot and
how much toe-in is required to offset that slop. Misalignment of the
brakes make setup harder, too.
The MAFAC brakes had a lot of play in their pivots--the plastic
bushings were worse than the brass ones given the deformation under
load, but harder to set up given that you have to offset the extra
deformation when toeing the brakes in.
Once toed-in appropriately they all seem to play well. My Alex Singer
was toed-in by the builder, and never made a peep; my René Herse
brakes howled until I (who assembled the bike) took a crescent wrench
to the arms. My brother's Kelpie (Dia-Compe 610s) required no
modification at all to be silent.
The Paul brakes have a fair bit of play in their adjustable pivots,
and required an exaggerated toe-in to (mostly) eliminate it. The
sticky Salmon pads don't help (but improve ultimate braking capacity).
The Compass brakes have less play in the pivots than do any of the
MAFAC, Paul, or Dia-Compe/Weinmann brakes I've had to mess with, and,
assuming the pivots are properly brazed (the tolerances are tight for
brazed-on centerpulls vs a cantilever brake), they don't squeal. The
two Boulder Bicycle centerpull setups with which I've been directly
involved were silent out of the box, but neither required any work to
get the pads parallel to the rim under hard braking, either. Toe-in
adjustments on any of the historical/repro brakes is a hassle--filing
the mounting washers or cold-setting the arms--but results in a quiet
brake, eventually. I am on the fence whether it is worth it vs a
properly set up cantilever. For short- and medium-reach systems,
they're a (big) improvement. For the long reach brakes, brazed-on
centerpulls are better than their dual-pivot competition, but vs a
cantilever? It is a hard call.
Best Regards,
Will
William M. deRosset
Fort Collins, CO
Best Regards,
Will
On Friday, June 3, 2016 at 7:54:54 PM UTC-6, Steve Palincsar wrote:
On 06/03/2016 09:40 PM, ted wrote:
> Tim,
> Just thought you may want to look into the options, not
recommending a choice.
> The Paul and compass pads/holders are not interchangeable, the
slots in the brake arms are oriented differently. Look at pictures
of the Paul racer m model to see the difference more clearly.
Compass / Raids use what we now know as the smooth-post cantilever
pad
(Mafac originated that design and everybody else copied it) while the
Paul Racers use the thinline threaded V-brake style pad.
> Regarding squeal I've read conflicting reports on the
raid/compass brakes. Some say some say they have lots, others say
not a problem.
> I believe both the Paul and compass brakes have their adherents.
Precise location of brazed-on posts can have a lot to do with whether
the Compass/Raid squeals or not.
--
You received this message because you are subscribed to the Google
Groups "RBW Owners Bunch" group.
To unsubscribe from this group and stop receiving emails from it, send
an email to rbw-owners-bunch+unsubscr...@googlegroups.com
<mailto:rbw-owners-bunch+unsubscr...@googlegroups.com>.
To post to this group, send email to rbw-owners-bunch@googlegroups.com
<mailto:rbw-owners-bunch@googlegroups.com>.
Visit this group at https://groups.google.com/group/rbw-owners-bunch.
For more options, visit https://groups.google.com/d/optout.
--
You received this message because you are subscribed to the Google Groups "RBW
Owners Bunch" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to rbw-owners-bunch+unsubscr...@googlegroups.com.
To post to this group, send email to rbw-owners-bunch@googlegroups.com.
Visit this group at https://groups.google.com/group/rbw-owners-bunch.
For more options, visit https://groups.google.com/d/optout.
