archive research: bags, racks, brakes (LONG)

***snipped from the surly LHT owner's group, on racks:

When it comes to racks, something that most people tend to forget about is
"triangulation", which provides for a much stronger rack.

Tubus racks has triangulation built into them; that's why they see to rock
solid. Triangulation helps prevent the rack from swaying side to side, which
is what you need when it is carrying fully loaded panniers.

How to tell if your rack has triangulation built into the design? Stand back
and look at it straight on from the rear. Do the sides slope inwards from
bottom to top? If so, it has triangulation built into the design, which
makes for a stronger rack.

I own a Tubus Logo rear, and a Tubus Duo front. the Logo is designed to keep
the panniers a bit higher, and more towards the rear, and the deck is about
an inch or so higher than the rails that the panniers will hang on to, which
I find very convenient for whenever I need to remove my Arkel Tailrider
trunk bag; easier to get at the tabs that way. The Duo is a very simple, yet
strong design for the front, which is what I wanted to end up with. The Nice
rack looks really skookum, but it also appears too bulky for my liking.

***on canti bosses:

Last night, in a posting about canti bosses I wrote.

"Then I stick the whole thing together with 56% silver, including the bolt."

In case there is anyone on the list that wasn't here for the previous
discussion on using silver for canti bosses;
This is a very critical safety area. Unless you are extremely confident in
your ability to get a perfect bond with silver, stick to brass.

Mark Stonich;
BikeSmith Design & Fabrication LLC

***on canti boss jigs:
> Does anyone have plan for a jig for cantilever brazeons?

A bar with two holes works great.

Just looked at Sheldons; way too much work and too many parts in my opinion.

Here's what I did. I had a scrap chuck of aluminum maybe 3/4" thick from
school metal shop. Everyone machines things in aluminum all the time so
should be easy to come by.
I measured the width of a current mtb's cantilever's. Look at / measure
more then one, also look at your own bike's stay/fork blade width. Want to
get a width where the brakes will work and can get a good braze joint.
Drill two holes (i think 3/8" drill) with a drill press (work up to a 3/8"
and hold securely !, Use a sharp, new drill to make sure the holes go
straight and perpindicular). If you screw up the width, just drill new
holes in same chuck of aluminum. Push in bosses (they should just fit snug)
and also hold them with boss bolts, line up little spring holes, and round
file boss bottoms until both profiled for nice fit onto stay tubes or fork
blades. Obviously you'll first need measure carefully from axle to make sure
you get the bosses in the correct spot and profiled for that spot. You have
some adjustabiliy with the brakes but obviously want to try to get in the
center of that adjustability. I would also double check the bike that is
your "master" to make sure the brakes are not at one extreme or another of
their adjustability. Finally once you get the filing done hold the bosses
in place with a c-clamp and another bar (I use a flexible thin almost sheet
metal bar) so that stays or fork blades are sandwiched. Measure. Tap to
move. Eye ball. Stand back and eye ball. Re measure. Then braze away.
Piece o cake and o so cheap. Kind Regards, John

***on brass vs. silver for braze-ons:

I was advised (AT)60 pair of bosses ago by a much more
experienced brazer than myself that silver didn't have
enough strength for the shear forces that cantilever
brakes endure. It also has worked out that most cast
or machined bosses absorb most of the heat and that
it's possible to get 1/16" brass to flow with minimal
reddening of the seatstay tubes.
David Feldman
--- t rodi <t_rodi(AT)> wrote:
> I prefer the speed of silver...that extra time to
> get the stay up to brass
> temp is just too much!!!
> (seriously, I just prefer the feel of the 50N versus
> brass)
> Tom

***canti boss brazing

I use Welco 17 for canti bosses. Have never had one come off,
no matter the circumstance. Silver would probably work, but

More important I think, than what you use to stick the cantis
oin, is how you do it. Canti bosses are EZ to misalign, and it
is easy to spot misaligned canti mounts on a finished frame.
Especially with V-brakes. Take your time and put them on the
right place the first time. If you miss, leave them where they
are, 'cause taking them off you'll likely cook a stay.

just my 2 cents


***another opinion
At 5:25 PM -0500 5/28/03, goodrichbikes wrote:
>I have a question for the builders that choose silver over brass for
>putting on cantis- why? Sure the higher melting point of brass
>takes a little out of the seat stay but do people think this matters
>given the stay is mostly under compression? Inquiring minds want to

Since you've asked I'll tell ya. I've always used silver because
that was what I was told makes for better braking because the silver
makes for a firmer joint than brass and you were less likely to
overheat the stay. I was also taught that you need to move as quick
as you can and make sure you have full coverage. I got my start out
in the alley behind The Bikesmith in Seattle brazing canti-bosses
onto old frames to make cyclocross conversions. We mostly used the
AVA bosses and a fixture made from a small piece of channel iron.
Before I could do them for customers I first had to try and destroy a
pair of bosses. This was done by brazing some on a junk frame and
then trying to rip them off with a BFC. The boss itself would tear
apart or the stay dimple and crumple before the joint came apart.
The next test was to do it to your own bike (old Lambert with a 27"
Bianchi fork) and try to destroy them. I was never able to and I
gave the frame to someone a few years back and he raced it with no
problems either and now it's a beater commuter.

I've been told the same thing about the strength of a silver brazed
canti-boss of brass brazed by a few other people over the years and
have never heard anything to the contrary until now. I think brass
would work just fine too if you're quick about it. I also think most
modern tubing is more forgivable as far as high temperature ranges.
I do like the idea of a larger radius joint you get with brass
filler. In the end I think they both will work fine if brazed
correctly. The only canti-boss I've ever seen fail in the joint on a
steel bike was one that was TIG welded, but I think the joint itself
was contaminated and there was little weld penetration in the stay.
Hope this answers some of your questions.
Missing the feeling of a torch
in his hand in Santa Barbara, CA.

***canti pivot spacing

I'm working from the 1999 Shimano book. The spacing between canti posts
depends a little on rim width. basically it's 77-85 mm, but on a road
bike you could probably go down to 75 and be fine..

I use 80 for mountain bikes and 85 for BMXers and bikes that are gonna
run V-brakes and wide rims.

Different V-brakes will have different tire clearances. This may not be
an issue with cantis.

Good luck


***nice specs
John Clay asked-
Do any of ya'll have a list of the industry standard dimensions of the radii
for locating canti bosses for common rim sizes (and 650b) that you would be
willing to share?

My reply-
700C(622) = 283mm
26"(559) = 253.5mm
650B(584) = 265mm
A post center to post center measurement of 80mm works best for most canti &
v brakes.

Curt Goodrich
Minneapolis, MN

***another view
I have used 45 or 50N for canti bosses on every frame I have built with
zero failures in 9 years. Both give you good penetration and a nice small
fillet without applying too much heat to the tubes.


Courtney Custom Cycles

***from fred parr
>From Freddy,
>I still use the Allstate 11 on the front fork and 45 or 56% on the rear,
>never had a bosse come off,
>but in the 60's they were all just yellow brass and they stayed on too..???
>only the old ones that were two pieces and needed to be sweated thru with
>brass were ever a problem.
>What Brandon is trying to relate is the condition of the mother steel is
>not effected by the silver solders like 56% and on a real thin frame could
>make a vibrating canti brake with high temp brass do to the softening of
>the steel, that was then this is now.. just not going to happen on bikes ..
>unless you want canti's on your time trail bike..
>Also note the Richards bike hold together for Champions day after day and
>He is one of the most careful and successful builders of all time..
>Brass is stronger but weakens steel in my opinion and careful fitting
>-skill and practice -and working clean make silver a safe and sane if not
>better choice.
>As I said, I worry so I use the Nickel silver on parts that pull during
>use, that is just me and I can sleep at night.

***rear hub spacing
If he buys pre-built road wheels, they will be 130. Its rare to have
a 700c with a 135mm axle (latest mtb spacing), likewise no non-custom
recent spec mtb wheel will use a 130mm axle. (however I own examples
of both pairings)

***more canti specs
The last time I asked about canti spacing, the number I got was 80mm
center to center, apparently from the literature of the big S. I
expect it should depend on the rim width, but they didn't mention a
correction. As to distance from axle, I was told 25mm less than the
bead seat diameter, which worked fine for the canti's I used.
(happened to be scott self energizing -- pre linear pull style.)

***brass vs. silver from the issimo
"Most people that learn to braze first have more problems
with silver than people that learn to silver first."

i agree. i learned to braze and build w brass but switched to
silver content rods about 5 years in. when you go through the
learning curve w brass as your chosen filler rod, you learn
more about heat, heating cycles, capillary action, and a whole
host of other topics that will help you troubleshoot down the road.
too often, 'brazing w silver' has this cache attached to it as though
you can do no wrong by dint of the lower amount of heat used. i
see that as a major problem and tangential to this thread about
canti post brazing.
it's hard 'to unring the bell', but if you're a silver content rod user,
trying turning up the oxygen, or using a bigger tip, or having some
doobage the next time your near the torch. the biggest crime you
can commit is being so careful that you assume that the rod will
do the work for you. when freddy says things like 'flow the joint'
(no pun intended...) i think it's great advice. get it hotter. work
faster. use 3 x more flux. it'll work out fine, trust me.
Richard Sachs Cycles

***more from issimo
i do all my cantis w 56% silver and lay up
a little fillet. no problems - that i know of!

the strength issue is irrelevent. it's cost.
it's more economical to use brass; once the joints
have cooled, that's it. use of silver alloyed rods is
a boutique-y thing, not an indicator of an improvement
or a quality establish-er.
the "skillful hands" part is the most germaine.
the skill is more important than the filler.

***whi is good for what
Brass- Loose fitting lugs, that will see a second brazing on top of them
(seat lug, ST/BB socket), Steerer/crowns, canti bosses, most bridges, rack
or fender eyelets which extend from the frame, drop out to stays/blades,
large dents or any area where I'm concerned about the strength VS surface
area or project where cost is an issue.

Silver- Close fitting lugs, Seat Stay to seat lug or tube, DT and CS to BB
sockets, blades into crown sockets, most braze ons, small dents (yes they do
happen), head tube "S", or any area where heat or minimal fillet size
matters and where cost is not a concern.

I do like silver's easier clean up and lower heat. I like brass's tolerance
of loose fit up and greater fillet ability. Brass flows better when the prep
is less then ideal. Brass costs less. Silver adds a "value" to the marketing
to most customers. I find myself trying to use brass more and more for my
own frames but still use silver for most braze ons.

Hope this helps. Andy S.

***on seatstay/seat cluster brazing from the big TP
> I always silver braze my seat stays to a silver brazed seat lug. Yes, I do
> get a crevice forming at the top where the line between the seat tube and
> seat lug can be seen. To take care of this problem, I apply a little extra
> flux to that area to keep it clean and then drop a tiny drop of silver in
> that crevice on each side of the lug. If you're skillful with the torch,
> that drop is so small that clean up never amounts to much.
> I have several tricks to attain maximum contact area between the seat
> stays and the seat lug.
> 1. Sometimes I file a groove into each side of the seat lug with about a
> 10 or 12 inch round file. This allows the stay to lay in a small furrow on
> the side of the lug which increases surface area.
> 2. I often use semi wrap around caps on the stays and curve them around
> the upper part of the lug. Just leave extra cap material extending beyond
> the top of the stay. Then shape it into a nice point that extends about 6
> or 7 mm beyond the top of the stay and bend it cold so it wraps over the
> contour of the lug. This provides lots of surface area for silver to
> gather under.
> 3. Full wrap around seat stays provide a generous amount of surface area.
> I do full wraps the same way I do partiel wrap arounds except I make them
> much longer and have them touch in the middle.
> 4. By properly positioning the frame during brazing and being gentle with
> the flame, I can depend on surface tension to hold a fairly large fillet
> between the seat stay and the seat lug.
> 5. I oftentimes attach the cap to the top of the seatstay with brass. This
> prevents the sub-assembly from melting when the stays are connected to the
> sides of the seat lug.
> Sincerely,
> Tim Paterek

***on silver brazing from fred parr
Dear James,
Yes the Nic is the tinning element, Here is the rest of the story..
The old silver 45% had Cadmium in it to enhance the flow, but still =
allow it to be plastic enough to fill small gaps..
Well with no Cad it is a lot more static about bonding.. the 50n is =
quicker to tin the parts and you may find it easier to make the tiny =
fillets you want?

56% is not acceptable to me for this work, I have seen it let go on =
beginners frames where they did not provide for enough contact area.. =
but many of the current builders use it in their proven designs, with no =

If I make an intricate seat stay hook up, I almost always pin it =
somehow, to make sure it can't work loose. I have also pretinned with =
56% in hard to reach areas where the heating is uneven and then flow 45% =
over it.

The old Eutectic 45% was a lot stronger than anything we have today, It =
I saw some failures on sprint bikes that required re thinking the =
contact areas myself-- of course that was over thirty years ago.

Just remember a little common nail is stronger than the rest of the =
sliver joint and can prevent a seat stay from popping loose during an =
impact such as a pot hole at speed.

Unless some has has more problems with the 50n that I don't know about I =
can see no reason not to use it?

It still is going to depend on what you find for results under you torch =

Good Luck

***the issimo on alignment
i drive all the pins through all the holes while everything
is fixtured. sometimes, not always, i'll tack the headlugs
on the front area. but that's it. the pins, and the setup that
is yielded from the fixture, ensures that the geometry mimics
the blueprint. alignment issues are just that-seperate issues.
they are dealt with viv-a-vis the alignment table.

***freddy parr on flux and rod
To All,
Pre placed flux or jet flux is most effective. a flux coated rod is fine to
use ,but will often not clean long enough or deep enough for lugs.
This is old knowledge.. real old.
Allstate 11fc is for fast constuction of mild steel bike frames such as
Huffys.. but used with welco 17 or allstate 11 paste flux - will make a fine
strong joint comparable to any.
I still use 45% silver on the entire lug type bike and I have bikes out
there that have been ridden hard for over 35 years.
Hank's lugs are so close to perfect that 56% is fine -but when in doubt, use
a stronger one such as 45%.
The seat stays will be fine if they are bedded with a little care and have
at least 5/8 of an inch of fillet on the lateral (on the side ones)
I have known Hank since He first cast some fork crowns and His products are
able to speak for themselves. To flow silver into a good tight lug requires
cleanliness and heat control, having flux on the rod is not going to do
anything but leave the operator with more flux to clean off.

Freddy Parr

***seat cluster brazing
Warning: this is from an amateur currently working on
frame #'s 14 and 15. I pin seatstay plugs to the lug,
flux the whole area generously, and try to keep 90% of
the flame on the plug/seatstay. On the three frames
where I have put a real cap on the seatstay, I have
brass-brazed the cap. Four other frames of mine have
seat lugs that were brass-brazed for exactly this
reason. My luck has held so far in not overheating a
seat tube and only getting that little bulge below the
bottom edge of the seat lug once; that was with a
Genius MTB seat tube and a big, heavy-walled Haden
David Feldman--- goodrichbikes

***practice stuff, kinda old
From: "Jon Kendziera" <jkendzie(AT)>
Subject: RE: [Frame] Another lurker, looking to buy junk lugs / tubes for
Date: Wed, 9 Mar 2005 18:53:17 -0600

Kris and anyone else interested,

I have lots of extra/spare tubing lugs, etc that I won't ever get around
to using.

1" top tubes, double butted (9/6/9 ...maybe?)

22.2 Round chainstay's (1.0 at the BB end)

14mm (at the top end) seat stays

Oval fork blades (1.0?)

Tons of pressed BB shells (classic size tubing 1 1/8" st and dt, 22.2
round cs)

Extra rusty brake bridges and dt shifter mounts (a bit of emery will
make them work)

A few reject fork crowns (good for practice)

Seat stays

And actually some nice Tange cast head lugs:

All the tubing is unknown manufacture and I don't really know exact
thicknesses...but its on the thicker side of things. All in good shape
w/little to no rust. Great practice stuff.

I've been doing $20 + 6 shipping for a box full of two each of all the
tubing (that's two pairs of cs, fb and ss). Some BB shells, a fork
crown, some shift mounts, and some brake bridges. If you want other
quantities let me know. Some BB shells and a fork crown.

Tange head lugs=$10/set. They are actually nice and I plan on building
some frames w/them myself.


***vent hole drilling
This brings up another one of my early mistakes

when I got a can of FrameSaver, I realized that I didn't have enough
holes in my frame. While i left one hole in each ture for air pressure
relief, i didn't leave two holes. From now on I i will be using two good
holes in each tube, and at least one on each tube I plan to make the
lowest point- somehow for drip drying.

I discovered that while really cool, having the one breather hole of the
seat stays inside the brake bridge leads to much annoyance getting all
the water out. bad idea #473.

I just hope that soon I run out of bad ideas.....

ed westhead

***a window in to issimo's build sequence
>if you're asking how/when i file the drpoouts??
>the main triangle is made.
>i braze the dropouts into the chainstay at the proper confluence.
>i file them.
>i mock up the rear wheelbase w the main triangle.
>i cut seatstays to length.
>i pin the chainstays to the bb.
>i pin the seatstays to the seatlug and dropouts.
>i remove it all from the fixture.
>i braze the seatstays to the dropouts.
>i un-pin all the un-used pins.
>i file the dropouts into the seatstays.
>i re-pin the left and right stay assemblies
> into the bb and seatlug.
>i braze the chainstays into the bb and the
> seatstays onto the seatlug - w'o using
> a fixture. the pins are my locaters.
the main triangle is built and
completely finished/filed/machined, etc before
i do any of the stuff i noted earlier re the
rear stays.

***issimo on pinning
the pins hold all the parts in the proper angles
because they are wdged in air-tight. the entire
rear assembly remains pinned to the finished front
triangle. the two seatstay tops are pinned to the
seat lug, the finished chianstay/dropout assys are
pinned into the bb, and the seatstay bottoms are pinned
to the dropouts. i use a surrogate axle to space the
dropouts and a clip to keep the seatstays close together.
after i braze the setastays to the dropouts and then file
them up, all angles and dimensions remain true to the
fixture. after the right and left sides are done, i re-
pin them into the seat lug and the bb and braze those
areas. no fixture. just pins.

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