Tech Specifications

[Charles Lathe]

Campagnolo seems to do a good job of providing framebuilders with specifications on their website, but I can't find much information for Shimano or Sram. Paul tells you where their centerpull brakes want their studs, but they don't say anything about where their inline or cantilever brakes want their studs.

I have a document here that says the Shimano specification for cantilever studs is 253.5 mm from the axle, but I can't find the source of this spec. If that spec is right, then I'm guessing Shimano also has an idea about how far apart the studs should be for v-brakes, but I sure can't find it on their website and it sure doesn't come with their brakes.

If Shimano and Sram publish specifications and you know where they publish them, please tell me. I brazed on a set of studs for some Avid Single Digit 7s and I sure wish I'd used some studs that were a little closer together on the back, but I couldn't find any info when it was time to melt silver.

Regards, Chuck Lathe
Franklinville, NC

[suspectdevice]

Shimano USA has a big and beautiful 3-ring binder with every conceivable specification and dimension you may need for their products. Call them and tell them you are a framebuilder, and they'll put you in touch with the right guy.

[suhacycles]

I have a document here that says the Shimano specification for cantilever studs is 253.5 mm from the axle, but I can't find the source of this spec. If that spec is right, then I'm guessing Shimano also has an idea about how far apart the studs should be for v-brakes, but I sure can't find it on their website and it sure doesn't come with their brakes.

Huh... I heard the spec was 285mm from the axle... yeah, confirmation would be nice!

[Dave Porter]

Doesn't Sutherland's shop manual still have all that info?

[steve garro]

Campagnolo seems to do a good job of providing framebuilders with specifications on their website, but I can't find much information for Shimano or Sram. Paul tells you where their centerpull brakes want their studs, but they don't say anything about where their inline or cantilever brakes want their studs.

I have a document here that says the Shimano specification for cantilever studs is 253.5 mm from the axle, but I can't find the source of this spec. If that spec is right, then I'm guessing Shimano also has an idea about how far apart the studs should be for v-brakes, but I sure can't find it on their website and it sure doesn't come with their brakes.

If Shimano and Sram publish specifications and you know where they publish them, please tell me. I brazed on a set of studs for some Avid Single Digit 7s and I sure wish I'd used some studs that were a little closer together on the back, but I couldn't find any info when it was time to melt silver.

Regards, Chuck Lathe
Franklinville, NC

253mm is the canti/V measurement for 26". 283mm is the 700c measurement {generic}. Paul brakes differ from others. - have them there. post-to-post changes with brake model & rim width, but 70mm is pretty safe, 65mm-ish for narrow rims. this is the stuff you write on the walls........also, put those spigots on with brass :}. yes, i have seen silvered ones come off. Garro.

[marten]

it needs some updating, but here's the list from my wall:
pdf

[Chauncey Matthews]

Lot's of good Shimano tech here http://pvdwiki.com/index.php?title=S...mebuilder_Info from Peter Verdone. He does a great job of recording his research and framebuilding experiments.
But like Steve says, it varies from brake to brake,the rim width, and depending on application. For instance, I've found 253 to be a bit high when using horizontal dropouts.

[Charles Lathe]

Thank you Chauncey. I will give that site a good looking over. I have a Shimano book with a lot of specs in it, but I don't think it's the one Mickey writes about. and it looks like this webpage has a lot more than my book. Campy does such a good job of putting this stuff out there on the web where it is easy to find, I don't understand why the others don't try to do as well.

Regards, Chuck

[Charles Lathe]

also, put those spigots on with brass :}. yes, i have seen silvered ones come off. Garro.

If silver brazed brake studs come off, they weren't properly brazed on. Check the literature. Properly done, silver brazing is several times stronger than brass. Brass is plenty strong enough for brake studs, though.

Regards, Chuck

[e-RICHIE]

If silver brazed brake studs come off, they weren't properly brazed on. Check the literature. Properly done, silver brazing is several times stronger than brass. Brass is plenty strong enough for brake studs, though.

Regards, Chuck

you don't need/want the strength atmo.
ductility is your friend.
brass...

[Curt Goodrich]

Brass has a higher tensile strength than silver so if all other variables are the same the brass brazed joint is stronger. But the brass brazing temps reduce the tensile strength of the surrounding tubes where the silver brazing doesn't affect the tensile strength of the surrounding tubes. Chuck- I think that's where you're confused. Like Garro, I've seen silver brazed pivots break off but only only when bad things happen. When those same bad things happen the brass brazed pivots stay put. I think of it this way. Brake pivots see a pretty big load (as opposed to a split stop) and they're small. So ultimately there's not that much filler holding them on. Given that, I opt for a stronger filler like brass. Still there's times when I end up silver brazing the pivots on if I'm really close to the crown like on Paul Racers but then I make sure to use a bit extra silver.

Shimano recommends a pivot center to center measurement around 80mm +/- 3mm for their cantilevers and V-brakes. I put the Paul ones there too and they work great. I hate when pivots are too close together.

[e-RICHIE]

Still there's times when I end up silver brazing the pivots on if I'm really close to the crown like on Paul Racers but then I make sure to use a bit extra silver.

when i do those i brass braze the studs to the blades first and then reassemble the fork parts and build it normally.
if the blades are cut to length it's easy to locate the canti hash marks and then add the posts atmo.

[Charles Lathe]

This is from the American Welding society:

"Brazing with a silver-containing filler is one of the most versatile methods of metal joining in use today, for a number of reasons.

It is cost-effective. There is very little braze alloy required to produce a brazed joint. With properly designed joints, this kind of brazing will compare favorably with any other metal joining method.

The joints produced are strong. Engineers and designers frequently request strength data of brazing filler metals, making the assumption the brazed joint will only be as strong as the brazing filler metal itself. Surprisingly, depending on the base material, properly made brazed joints will exhibit tensile strengths far greater than the filler metal. Typically, braze-joint strength is closer to the yield strength of the base metal being joined. As an example, the filler metal BAg-1 has a tensile strength of 50 ksi. As
shown in Fig. 1, 18-8 stainless steel joints brazed with BAg-1 have tensile strengths in excess of 120 ksi, far greater than the filler metal itself.

The joints produced are ductile, able to withstand considerable shock and vibration.

The joints are generally produced easily and quickly.

It can join dissimilar metals well. You can easily join metals with widely different melting points.

It can join metals with vastly different cross sections. For example, joining 0.005-in.-thick copper foil to a 1-in.-thick steel plate would be a challenge to weld, but relatively easy to braze.

Joints have excellent stress distribution and heat transfer. The braze fillet formed is ideally shaped to resist fatigue. It is highly adaptable to automation. Typical automation methods include torch, furnace, induction and resistance heating.

It is essentially a one-operation process. There is seldom any need for grinding, filing or mechanical finishing after the joint is completed. This is particularly beneficial for assemblies to be plated.

The joints virtually make themselves by capillary action, so complex geometries are as easy to join as simple geometries."

From Harris about Safety-Silv 56 : "Ductility is high."

From Canada Metals about the benefits of silver brazing: "DUCTILE Joints will withstand considerable vibration, expansion, contraction or shock."

I don't have any stake in this and I am not at all opposed to using brass. I just don't like that silver brazing gets a bad rap on framebuilder forums. In the rest of the metal assembly world it is held in high regard.

Regards, Chuck

[marten]

Check the literature. Properly done, silver brazing is several times stronger than brass. Brass is plenty strong enough for brake studs, though.

Regards, Chuck

Specs are woderfull, but only valid for a very specific set of circumstance ie a very narrow gap. The moment you start filletbrazing it's a whole new ballgame, and then silver has a rather poor peelstrenght. Silver is usually strong enough untill you encounter that large tree crossing the road, and then I'd rather have assembly of 11 bent tubes to discuss, than something with joints which came apart.

[Eric Estlund]

I'm not going to tell anyone how to build their bikes, but after doing several thousand of these in bronze (thousands of which were single operation with no clean up) I don't see a benefit for me to do them any other way.

Back on topic- I generally build to Shimano spec, but for brakes I haven't used before I'll hold them up with the pads positioned how I like them and take note of any surprises. I generally don't like locking a customer in to a single brake option unless they ask for that, so if a particular unit doesn't allow pad adjustment or a different brand replacement it warrants a conversation. SRAM and Campy have similar spec sheets to the Shimano one, just give the head offices a call and they are good about getting you an official copy or just answering it so you can write it on the wall. Same with the boutique folks.

[Curt Goodrich]

I don't see in any of these replies where silver brazing is getting a bad rap. What I see is people with real world experience sharing real information. Industry uses many different brazing fillers other than silver. Why? Because different fillers have different properties. They're just tools and like any tool, it's up to the operator to choose the right one and use it properly. What is absolutely true is making bicycles doesn't resemble what the rest of the brazing industry deals with.

[abbeyQ]

i took me almost 18 months to finally get a copy of the shimano spec book. but then i was going thru a local rep and i think that was 17.5 months of the problem. I thought I knew a lot about bicycles until i really started reading that book, their are specs in their for things that never even crossed my mind. Even though I have the book i still like to double check things with real parts to make sure it is going to work, but that probably has to do with my level of experience and the shoe string i operate on.

[steve garro]

This is from the American Welding society:

.



It can join metals with vastly different cross sections. For example, joining 0.005-in.-thick copper foil to a 1-in.-thick steel plate would be a challenge to weld, but relatively easy to braze.





Regards, Chuck

the AWS also states that 4130 is not join-able by bronze welding.........also, brazing a piecs of .005" foil to a 1" block is easy? i don't care what you do, but: just join two spigots to a piece of 5/8" scrap - one with silver, one with brass & reef on em'. we are just trying to help - really. cranking on a little fillet with a full canti arm is allot of torque.... Garro.

[EricKeller]

I assume Mr. Lathe is talking about using a silver filler that builds a fillet. In which case I'm pretty sure there's nothing wrong with using it on canti posts. However, I do think that the quote from AWS is talking about using silver on something like a lugged joint, a thin layer over a large surface area. Silver is quite strong if the tolerances are tight.

[Charles Lathe]

Shimano USA has a big and beautiful 3-ring binder with every conceivable specification and dimension you may need for their products. Call them and tell them you are a framebuilder, and they'll put you in touch with the right guy.

Thanks Mickey,

I found the guy, Chad, and got the binder.

Chuck