Jan,
I am really enjoying your informative posts on brake technologies and designs. Thanks for enlightening me. (Nothing like hanging out in Dale's garage, talking about bikes with 1600 of my closest friends!)
Your comments about CP and SP brakes staying centered or not below may be correct from a theoretical standpoint, but I have had both types of brakes (CP and SP)"spring" back unevenly and/or asymmetrically due to sticky pivots, springs of unequal strength/wear, and other problems. On-road braking performance depends not only on product design, but on proper setup, good maintenance, and good luck on the road (As in avoiding "hidden" pot holes that can make round, true rims wobbly). The bending required to properly toe in Mafac Racers was very hard for me to get precisely right, and I often ended up with slightly asymmetrical brake pads, no matter how hard I tried.
Learning all the time, I am appreciatively yours,
Jon Spangler (Normally in Alameda but emailing from Redwood City, California USA for the night)
-----Forwarded Message-----
>From: classicrendezvous-request@bikelist.org
>Sent: Jan 21, 2009 12:00 PM
>To: classicrendezvous@bikelist.org
>Subject: Classicrendezvous Digest, Vol 73, Issue 97
>
>Send Classicrendezvous mailing list submissions to
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>
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>CR
>
>Today's Topics:
>
> 1. Re: Who has trouble stopping with vintage sidepulls? (Jan Heine)
> 2. Re: Lugged Viscounts (Alex Schultz)
> 3. Trouble stopping with vintage sidepull brakes and hand
> strength (Tom Sanders)
> 4. Failure to sign off on that last post on brakes (Tom Sanders)
> 5. FS-Stronglight Mod.93 triple crank (twowheels@verizon.net)
> 6. Re: Who has trouble stopping with vintage sidepulls? (Phil Brown)
> 7. Re: Who has trouble stopping with vintage sidepulls?
> (Daniel Artley)
> 8. Re: Lugged Lambert on Ebay (Dickey)
> 9. Re: Grandis decals (Bob Johnson) (globallyoff@s2ki.com)
>
>
>----------------------------------------------------------------------
>
>Message: 1
>Date: Wed, 21 Jan 2009 09:09:10 -0800
>From: Jan Heine <heine94@earthlink.net>
>Subject: Re: [CR] Who has trouble stopping with vintage sidepulls?
>To: <haxixe@gmail.com>
>Cc: classicrendezvous@bikelist.org
>Message-ID: <a0623095ec59cfa6383a9@[192.168.1.33]>
>Content-Type: text/plain; charset="us-ascii"; format=flowed
>
>At 6:15 PM -0800 1/20/09, Kurt Sperry wrote:
>
>>Thus I expect any significant advances in braking power since the '50s
>>to have been either down to lower friction cables/housings, better
>>brake friction pads/rims or simply changes in the lever ratio
>>compromises chosen.
>
>A few things have changed since the 1950s...
>
>- braking has become more important. On gravel roads, the limit is
>the adhesion of the tires on the road, not the power of the brakes.
>You can't let the bike roll on a gravel descent, then apply the
>brakes hard just before reaching a hairpin. (Touring bikes and
>tandems often used drum brakes to allow continuous braking without
>overheating rims.)
>
>- brakes now have shorter reach. In the 1950s, many racing bikes had
>huge clearances even with wide tires and fenders.
>
>- Caliper flex is a real concern. Short-reach brakes work much better
>than long-reach brakes. Disc brakes really are just ultra-short reach
>brakes. (The disc is a second, tinner rim, without tire, that can be
>clamped by a very small caliper.) Long-reach brakes work well if you
>move the pivots to shorten the lower arms.
>
>- Powerful brakes must be strong, as the forces generated are high.
>In the 1940s, numerous brake calipers broke in the Tour de France. I
>suspect this was because they used cast aluminum calipers. Mafac's
>Racer proudly wrote "Dural Forge" ("forged high-strength aluminum")
>on their calipers to show the difference.
>
>- Brake design wasn't always very brilliant. Many makers used the
>same upper arms for short- and long-reach brakes. Of course, the
>long-reach brakes had much less mechanical advantage. Has anybody
>experienced differences in braking power between short-reach and
>long-reach Campagnolo Nuovo/Super Record sidepulls?
>
>- As Kurt pointed out, if you increase the mechanical advantage, you
>have to put the pads closer to the rim. This is OK if your brake arms
>always return to the same spot. If they move over time, as they do on
>a sidepull, you'll have pads rubbing the rims after a short period of
>time. By having the brakes open further, you increase the amount of
>time between having to re-center the brakes. (Dual pivot brakes,
>cantilever and centerpulls return to the same spot every time.)
>
>A slight increase of mechanical advantage as you apply the brakes is
>useful. This is built-in with cantilever and centerpull brakes.
>(Campagnolo's Delta brake had this, too, but it was negated by the
>friction in all those pivots, which required great hand power to
>overcome. Also, I believe the Deltas had too much mechanical
>advantage - they use only a small portion of the available lever
>travel.)
>
>- cable routing is important. Modern handlebars often have very sharp
>bends. With "aero" routing, I suspect you loose significant braking
>power due to friction. (I once had a Bike Friday with a particularly
>tortuous and long cable routing to the rear cantilever brake, which
>had so much friction and compressed so much that the brake had no
>discernible effect - it did not slow the bike down. The same brake on
>the front, with a very clean cable run, was very powerful.)
>
>If all brakes were equal, then why did so many racers switch to Mafac
>centerpulls almost immediately after they were introduced? From what
>I have heard, Mafac did not sponsor anybody, the racers had to buy
>the brakes with their own money...
>
> From that, I conclude that the 1940s sidepull brakes were pretty
>lousy. By the 1960s, when Campagnolo introduced their sidepull,
>shorter brake reach and closer manufacturing tolerances made
>sidepulls competitive again (albeit not as good as centerpulls in my
>experience).
>
>Jan Heine
>Editor
>Bicycle Quarterly
>140 Lakeside Ave #C
>Seattle WA 98122
>http://www.vintagebicyclepress.com
>
>
>------------------------------
>
>Message: 2
>Date: Wed, 21 Jan 2009 09:14:57 -0800
>From: Alex Schultz <toolsparabolix@yahoo.com>
>Subject: [CR] Re: Lugged Viscounts
>To: CR <classicrendezvous@bikelist.org>
>Message-ID: <753078.10514.qm@web52011.mail.re2.yahoo.com>
>Content-Type: text/plain; charset="us-ascii"
>
>Hi there,
>
>I promised Clyde Putnam that I would take some pictures of a bike that I often see in the area. Says Viscount on the down tube, is fully lugged, and looks like it is a cheapo (!!!) bike. I still feel bad for the bike, sitting out there in Chicago winter, as you'll see in the pictures. Poor bicycle....Picture links below
>
>http://img.photobucket.com/albums/v207/parabolix/LuggedViscount001.jpg
>
>http://img.photobucket.com/albums/v207/parabolix/LuggedViscount002.jpg
>
>http://img.photobucket.com/albums/v207/parabolix/LuggedViscount003.jpg
>
>Enjoy! And as always, happy riding,
>Alex Schultz,
>Sick again in Chicago, IL
>
>
>
>
>
>
>
>------------------------------
>
>Message: 3
>Date: Wed, 21 Jan 2009 12:22:45 -0500
>From: Tom Sanders <tesanders@comcast.net>
>Subject: [CR] Trouble stopping with vintage sidepull brakes and hand
> strength
>To: <Classicrendezvous@bikelist.org>
>Message-ID: <001f01c97bec$e1aa6a30$a4ff3e90$@net>
>Content-Type: text/plain; charset="us-ascii"
>
>I have heard hand individual strength mentioned in this thread, but not that
>the effects of differing amount of it may be mitigated by the brake
>adjustment. Having fairly large and strong hands for a little guy I always
>keep the shoes quite close to the rim. This means that more strength is
>required for the brakes, however. If one adjusts them a bit further off,
>the time for the shoes tocontact the rim is only minimally increased and you
>are in the range where less hand strength is required to firmly engage the
>rim. When I read of brakes tests, I always wonder if they are set up
>identically for the tests or if they are just tried on different bikes.
>
>Truth is, I find nearly all vintage brakes adequate when set up well (a
>couple of notable exception do exist.mostly the more exotic looking ones)
>and that some brakes (cantilevers, for instance) can work almost too well.
>Caution must be taken in panic stops with them and judgement and experience
>may be necessary before the risk of an accident due to over braking can be
>ruled out. Nearly all of them are capable of putting you over the bars
>under some circumstances.
>
>In short, if your vintage brakes are not stopping you the way you'd like,
>try some adjustment (or different shoes) before you give up on them. A
>
>
>
>
>
>------------------------------
>
>Message: 4
>Date: Wed, 21 Jan 2009 12:24:46 -0500
>From: Tom Sanders <tesanders@comcast.net>
>Subject: [CR] Failure to sign off on that last post on brakes
>To: <Classicrendezvous@bikelist.org>
>Message-ID: <002401c97bed$28d65310$7a82f930$@net>
>Content-Type: text/plain; charset="us-ascii"
>
>
>
>Sorry for not signing off properly.every so often my darn E-Mail program
>just disappears or sends something all by itself. It did there.
>
>Tom Sanders
>
>Lansing, Mi USA
>
>
>
>
>
>------------------------------
>
>Message: 5
>Date: Wed, 21 Jan 2009 11:22:56 -0600
>From: <twowheels@verizon.net>
>Subject: [CR] FS-Stronglight Mod.93 triple crank
>To: <classicrendezvous@bikelist.org>
>Message-ID:
> <813559856.221340.1232558576859.JavaMail.root@vms226.mailsrvcs.net>
>Content-Type: text/plain
>
>Used Stronglight 93 cranks, 70's vintage, 170mm, 52/46/40 chainrings, 9/16th pedals. 52 and 46 have moderate wear, 40 has heavy wear. The 40 bolts to the 46 so it can be used as a double. Includes crank bolts, washers and original Stronglight dust caps. VG cond., some rub/wear near pedal holes. Asking $40. plus shipping. Shipping is CONUS only and Paypal is preferred. Thanks for looking.Jim AmmiratoW.Newton,MA
>
>
>
>------------------------------
>
>Message: 6
>Date: Wed, 21 Jan 2009 09:36:12 -0800
>From: Phil Brown <philcycles@sbcglobal.net>
>Subject: Re: [CR] Who has trouble stopping with vintage sidepulls?
>To: classic rendezvous <classicrendezvous@bikelist.org>
>Message-ID: <2f0b296c40d362e242a7232ddf3636b7@sbcglobal.net>
>Content-Type: text/plain; charset="US-ASCII"; format=flowed
>
>
>I haven't chimed in on this but what the hey, here I go.
>Flex it the enemy of braking. Older brakes compensated for this in a
>couple of ways but the most important was pad softness. Older pads were
>softer-cf: MAFAC-to follow the rim as the caliper flexed. Weinmann and
>Universal were the same. Remember how fast those pads wore out?
>In comes Campy with about the stiffest calipers made to the time. But
>they paired them with the hardest pads we'd ever seen. Remember how
>every ride was followed by a session picking aluminum flakes out of the
>pads? This was the "speed modulation" theory. Of course those non
>pelotonists among us needed to actually stop and hated picking our rims
>out of the pads so guess what? We switched to Scott Mathauser pads as
>soon as they came out.
>Viola! Braking problems solved.
>The problem is that modern pads are harder than vintage pads. Even if
>they are vintage pads they've hardened over the past 20 or 30 years on
>the bike shop shelf so now we have the worst of all possible worlds:
>flexy calipers with hard pads and poor stopping.
>I hope this brings some new thought to the discussion.
>Phil Brown
>Berkeley, Calif.
>
>
>
>------------------------------
>
>Message: 7
>Date: Wed, 21 Jan 2009 12:40:03 -0500
>From: Daniel Artley <dartley@baltimorecountymd.gov>
>Subject: Re: [CR] Who has trouble stopping with vintage sidepulls?
>To: Classic Rendezvous <classicrendezvous@bikelist.org>
>Message-ID: <497717A3.CB1D.00FE.0@baltimorecountymd.gov>
>Content-Type: text/plain; charset="US-ASCII"
>
>I guess that I'm lucky that I was a child of the seventies when I really
>got into nicer bikes. My first bike w/ caliper brakes was a new 1966
>Schwinn Supersport w/ Schwinn approved Weinmans and I never gave a thought
>about braking. Then my UO-8 w/ Mafac racers and chrome rims, perfectly OK
>till the rims got wet, then a bit scary. Then I moved up.
>
>It's only now that I've gotten the vintage bug and wish to ride authentic
>bikes from before my learning curve. So far I've just got the vintage
>fixed gear on the road that started with a pair of GB Coureur Plus's.
>Good thing I was riding fixed, my speeds weren't high and foot braking
>helped out too. Still a panic stop couldn't come near to what I'd been
>used to. Next the Synchron dual pivots. Better braking, but what a mushy
>feel, and just watching the calipers moving around on those nylon pivots
>... no wonder Mafac racers were such an improvement. The bike now has
>what was a NOS set of long reach Universal calipers that besides being
>more minimal, seem to stop the bike just a bit better. I've got the take
>offs in the bins for my next build, a Carlton International soon to be
>built up with a Sturmey FW. Should be nice for climbing most of the hills
>around here, but I'll be certain to start braking near the top of the
>steeper ones!
>
>Happy trails,
>
>Dan Artley, thinking it would be better to be off work riding on this
>Sunny, cold day in Parkton, Maryland USA
>
>Archive-URL: http://search.bikelist.org/
>vous.10901.1026.eml
>Date: Tue, 20 Jan 2009 14:50:59 -0700
>From: Mitch Harris <mitch.harris(AT)gmail.com>
>Subject: [CR] Who has trouble stopping with vintage sidepulls? ( http://sea
>rch.bikelist.org/query.asp?SearchString=%22Who+has+trouble+stopping+with+
>vintage+sidepulls%3F%22&SearchPrefix=%40msgsubject&SortBy=MsgDa
>te%5Ba%5D )
>
>Curious if anyone has trouble stopping with vintage single pivot
>sidepulls. I read on list here that they don't stop well, or only
>modulate or slow a bike, or are only for racers who merely need to
>moderate speed occasionally.
>
>...Lots of stuff ...
>
>--Mitch Harris
>Little Rock Canyon, Utah, USA
>
>
>
>
>------------------------------
>
>Message: 8
>Date: Wed, 21 Jan 2009 12:52:21 -0600
>From: Dickey <ogreer@bellsouth.net>
>Subject: Re: [CR] Lugged Lambert on Ebay
>To: <classicrendezvous@bikelist.org>
>Message-ID: <FB5FBA90C37E4982856D703B6209FDE8@cpugreer>
>Content-Type: text/plain; charset="iso-8859-1"
>
>That is more like the Lugged Viscount that Pro Mick Bennet used to ride.
>Dickey Greer
>West Monroe,La USA
>
>
>
>------------------------------
>
>Message: 9
>Date: Wed, 21 Jan 2009 13:26:48 -0600
>From: <globallyoff@s2ki.com>
>Subject: Re: [CR] Grandis decals (Bob Johnson)
>To: Johnsons <thejohnsons2@ntlworld.com>
>Cc: classicrendezvous@bikelist.org
>Message-ID: 1213.75.65.254.166.1232566008.squirrel@www.s2ki.com
>Content-Type: text/plain; charset="iso-8859-1"
>
>Jim Cunningham at Cycleart should still have the design. They had to make
>some for mine back in 2001. They worked from an article in High Times
>magazine from the mid 70's that had lots of pictures of a Grandis. The
>edition was called "Dealers Wheels" (I did not surscribe to High Times
>btw)...lol. They also kept some 1980s decals that I sent them. Reference
>my bike on the CR webpage. They did a great job. Maybe Cycleart will
>chime in.
>
>Keith Kessel
>Shreveport, La.
>USA
>
>
>On Wed, January 21, 2009 3:14 am, Johnsons wrote:
>> Hi
>> Can anyone help in my quest for a complete set of late 70?s/early 80?s
>> Grandis transfers?
>> I have tried the usual suspects, Giorgio at Vintage Transfers in Italy and
>> Greg at Cyclomondo in Australia to no avail.
>> Thanks
>> --
>> Bob Johnson
>> London UK
>>
>>
>>
>>
>
>_______________________________________________
>
>
>End of Classicrendezvous Digest, Vol 73, Issue 97
>*************************************************