Interbike

In article <[email hidden]>, Paul Hobson

Quoted message said:

To both of y'all...I've put 700x32 tires on my fixie that I ride around
in the city. It is pretty awesome. I think I can tell that they're a
little slower than narrower tires, but the comfort is great. Also, I
would feel better about riding on hard-packed dirt trails with these tires.

That many pre-1980s framesets featured horizontal dropouts and
fender/rack braze-ons is not the only reason that recommended them for
fixed gear conversions: often they were spec'ed for 27 inch (630mm
standard) wheels. Once outfitted with 700c (622mm) hoops the bike could
accommodate a great variety of tire sizes with full fenders installed,
maximizing the bike's use as an all-round, all-season ride.

The likes of Tektro and Shimano adding 47-57mm reach calipers to their
lines (though, IIRC Shimano never did drop their longer reach RX-100
model), is, hopefully, a welcome affirmation of the versatility of the
older standard. Sometimes going back to the future is the way to go.

Luke

Robin,
Have you tried either the Mitsuobota Trimline or Panaracer Col de la
Vie 650B (584mm) x 38 at 50psi?

Robin asks:

<What is it that makes a 650B tire "cushy"? >

What makes 650B tires "cushy" is the fact that the Mitsuboshi Trimeline
or Panaracer Col de la Vie are fat 38mm wide tires. Runned at 50psi and
you get that ride that feels like you're riding on "fast marshmellows."
You need to try these tires....

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Ed Sullivan <[email hidden]> writes:

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Further, Tektro is coming out with a new high tech CENTERPULL brake
that will make even the most geekish of you drool over:

http://kogswell.com/images/tek725.jpg

Quoted message said:

Are you sure that is a "centerpull" brake? It doesn't pull from the
center like my Dia-Compes, rather it pulls from the side like a V
brake.

Just as the V-brake is a cantilever, being mounted on cantilevered
posts on the fork, this is a centerpull with the cable re-routed out
the side. It's geometry is the same as centerpull brakes of old,
having a bridge with pivots on both ends and pads that climb into the
tire with wear. It appears designers of such brakes have a fetish
about symmetry without functional reason.

I wonder what your suggestion for the design of a brake suitable for a
frame and fork without cantilever bosses and with quite long reach
might be. The symmetrical pivots on the bridge ot the brake posted at
least allow for relatively short and thus potentially stiff arms. My
experiences with sidepull brakes with something like 70mm reach are
very bad. Even as dual pivot versions they are just too flexible to
work satisfactory. Most of them are very cheap units also, which makes
comparision to today's road and MTB brakes a bit unfair. On the other
hand, despite being extremely light, my 55mm C.L.B. sidepull brakes
work nicely. But then they would most certainly work better with
shorter arms. With even longer reach they might well be quite useless
unless one would add lots of flesh to all parts.

Guenther

G?nther Schwarz said:

Quoted message said:

Quoted message said:

> Further, Tektro is coming out with a new high tech CENTERPULL
> brake that will make even the most geekish of you drool over:

http://kogswell.com/images/tek725.jpg

Quoted message said:

Quoted message said:

Quoted message said:

Are you sure that is a "centerpull" brake? It doesn't pull from
the center like my Dia-Compes, rather it pulls from the side like
a V brake.

Quoted message said:

Quoted message said:

Just as the V-brake is a cantilever, being mounted on cantilevered
posts on the fork, this is a centerpull with the cable re-routed
out the side. It's geometry is the same as centerpull brakes of
old, having a bridge with pivots on both ends and pads that climb
into the tire with wear. It appears designers of such brakes have
a fetish about symmetry without functional reason.

Quoted message said:

I wonder what your suggestion for the design of a brake suitable for
a frame and fork without cantilever bosses and with quite long reach
might be. The symmetrical pivots on the bridge to the brake posted
at least allow for relatively short and thus potentially stiff arms.
My experiences with sidepull brakes with something like 70mm reach
are very bad. Even as dual pivot versions they are just too
flexible to work satisfactory. Most of them are very cheap units
also, which makes comparison to today's road and MTB brakes a bit
unfair. On the other hand, despite being extremely light, my 55mm
C.L.B. sidepull brakes work nicely. But then they would most
certainly work better with shorter arms. With even longer reach
they might well be quite useless unless one would add lots of flesh
to all parts.

Flexibility of the pictured brake is entirely dependent on the reach
and the thickness of the elements. The reach is from the center bolt
to the brake pads, whether sidepull or centerpull with just as much
bending length either way. I see no benefits in the centerpull that
has an awkward cable pull while pivoting its brake pads in an inclined
arc from outboard pivots. If your sidepulls won't make it then a
centerpull won't either. Get a good sidepull.

Jobst Brandt

When using 650B (584mm) wheels, one of the main problems, besides
availability of tires, is the fact that you need longer reach brakes
than what is currently available with sidepulls. What Grant Petersen
found was that Centerpull brakes come with reach from 62-78mm long.
The Dia Compe 750 sold by Rivendell solves this problem. The new Tektro
ones are suppose to have a longer reach too. Its my understanding that
there is no sidepull currently available with a reach longer than 57mm
or 59mm.

bfd said:

When using 650B (584mm) wheels, one of the main problems, besides
availability of tires, is the fact that you need longer reach brakes
than what is currently available with sidepulls. What Grant Petersen
found was that Centerpull brakes come with reach from 62-78mm long.
The Dia Compe 750 sold by Rivendell solves this problem. The new Tektro
ones are suppose to have a longer reach too. Its my understanding that
there is no sidepull currently available with a reach longer than 57mm
or 59mm.

Kogswell claims the calipers they sell will reach to 64mm:
http://kogswell.com/brakeDESC.html

Many BMX sidepull brakes are very long reach- up to 100mm or so, I
think:
http://harriscyclery.net/site/page.cfm?PageID=49&SKU=BR7266

Jeff

Quoted message said:

G?nther Schwarz said:

Quoted message said:

>> Further, Tektro is coming out with a new high tech CENTERPULL
>> brake that will make even the most geekish of you drool over:

http://kogswell.com/images/tek725.jpg

Quoted message said:

Quoted message said:

Quoted message said:

It appears designers of such brakes have
a fetish about symmetry without functional reason.

Quoted message said:

I wonder what your suggestion for the design of a brake suitable for
a frame and fork without cantilever bosses and with quite long reach
might be. The symmetrical pivots on the bridge to the brake posted
at least allow for relatively short and thus potentially stiff arms.
My experiences with sidepull brakes with something like 70mm reach
are very bad. Even as dual pivot versions they are just too
flexible to work satisfactory. Most of them are very cheap units
also, which makes comparison to today's road and MTB brakes a bit
unfair. On the other hand, despite being extremely light, my 55mm
C.L.B. sidepull brakes work nicely. But then they would most
certainly work better with shorter arms. With even longer reach
they might well be quite useless unless one would add lots of flesh
to all parts.

Flexibility of the pictured brake is entirely dependent on the reach
and the thickness of the elements. The reach is from the center bolt
to the brake pads, whether sidepull or centerpull with just as much
bending length either way.

I agree. However, comparing existing designs for both types I find that
sidepull brakes tend to be lighter and, as a consequence, more
flexible. The C.L.B. I mentioned pushes that to the extreme being one
of the lightest brakes ever made.

Quoted message said:

I see no benefits in the centerpull that
has an awkward cable pull while pivoting its brake pads in an inclined
arc from outboard pivots. If your sidepulls won't make it then a
centerpull won't either. Get a good sidepull.

Most fortunately I do not need one at the moment. The ones I am aware of
are way lighter and therefor potentially more flexible than the Tektro
pictured. I might have a hard time finding a well made sidepull brake
for long reach. But then I asked for your suggestion for a design and
not for an available product.

Günther

G?nther Schwarz said:

Quoted message said:

I see no benefits in the centerpull that has an awkward cable pull
while pivoting its brake pads in an inclined arc from outboard
pivots. If your sidepulls won't make it then a centerpull won't
either. Get a good sidepull.

Quoted message said:

Most fortunately I do not need one at the moment. The ones I am
aware of are way lighter and therefor potentially more flexible than
the Tektro pictured. I might have a hard time finding a well made
sidepull brake for long reach. But then I asked for your suggestion
for a design and not for an available product.

I would build a sidepull caliper identical to the Campagnolo Record
brake of old, but with a concentric return spring to get over the poor
centering of those brakes after their sliding return springs get
dirty. I like my brakes except for that feature and have used them
since the 1960's when they were introduced.

Jobst Brandt