Types of Schwinn frame construction

[Schwinn Sales West]

Did Schwinn discontinue using brazing or was it used through out there time in some capacity? Would there always be the ability to add brazing to a weld?

Welding joins metal by "actually melting the two surfaces" together. The heat necessary can be supplied several ways, but a flame or electrical resistance is the most common source.

Brazing is a low temperature process that joins the steel at a much lower temperature, the best way to explain it is, it is a process much like Soldering but using brass as the joining product. You can Braze over a (steel) weld, but you cannot weld over a Brazed joint. It's very difficult to clean (grind) all of the Brazing off.

John

 

[SirMike1983]

It's amazing how newer forms of welding, particularly on aluminum frames, revolutionized bicycle manufacturing. It took welding from something you did with thick-walled, heavy steel tubes to something you could reliably with light material on a huge scale. Welded steel frames with thick-wall tubes became obsolete and lugged/brazed bikes became boutique in some cases (or obsolete in many other cases).

 

[AS-1]

The 92 GT Zaskar, 6061 Aircraft aluminum, you can pick the frame up with one finger. Schwinn tried to chase GT when they brought out the Homegrown but it was really DOA...by then every kid on the block was a Hans Rey wannabe.

 

[AS-1]

The 1991 GT Xizang, Titanium, lighter than the Zaskar, controlled welding. Magnificent bike!

 

[AS-1]

1983 Specialized Stumpjumper, first generation lugs. Beside this bike, the Sidewinder looked like a miscarriage. The writing was on the wall. Goliath was spending millions of dollars of money he had to borrow and Mike Sinyard was paying cash for finished bikes.

 

[Grey Ghost]

Did Schwinn discontinue using brazing or was it used through out there time in some capacity? Would there always be the ability to add brazing to a weld?

Lugged frames, such as those used on most European racing bikes at the time were joined using brass, or occasionally silver, filler. Later, lugged frames were glued together. Many early aluminum frames such as Vitus were glued using lugs. These lugs weren’t as fancy as the high end steel frame makers like Masi or Colnago used, they were simple round joints with no fancy filigree.

A few titanium and CF frames tried glued lug frames, but, by then, companies like Teledyne, and later LiteSpeed, had learned how to weld titanium tubing together. GT and others followed suit. Cannondale was mastering aluminum frame welding several years before Kestrel, and later, Trek, began tthe OCLV process of CF frames, thus, bypassing lugs, braising, and welding altogether.

Surprised nobody has mention butted tubing, that’s another aspect of frame building that allowed thinner, higher tensile strength, steel to be joined together using lugs and braising. Those steels didnt like being welded.Columbus, Reynolds’s, Tange, Ishiwata were the main butted tubing manufacturers.Tru-Temper blew them out of the water towards the end.

I think Tru-Temper welded their awesome Olympic winning steel frames but by then the steel frame era had run its course. Too bad, that was some incredible material. Too bad Nelson Vales ruined his racing career shoving white stuff up his nose after those Olympic wins, dude had some legs.

 

[Schwinn Sales West]

Lugged frames, such as those used on most European racing bikes at the time were joined using brass, or occasionally silver, filler. Later, lugged frames were glued together. Many early aluminum frames such as Vitus were glued using lugs. These lugs weren’t as fancy as the high end steel frame makers like Masi or Colnago used, they were simple round joints with no fancy filigree.

A few titanium and CF frames tried glued lug frames, but, by then, companies like Teledyne, and later LiteSpeed, had learned how to weld titanium tubing together. GT and others followed suit. Cannondale was mastering aluminum frame welding several years before Kestrel, and later, Trek, began tthe OCLV process of CF frames, thus, bypassing lugs, braising, and welding altogether.

Surprised nobody has mention butted tubing, that’s another aspect of frame building that allowed thinner, higher tensile strength, steel to be joined together using lugs and braising. Those steels didnt like being welded.Columbus, Reynolds’s, Tange, Ishiwata were the main butted tubing manufacturers.Tru-Temper blew them out of the water towards the end.

I think Tru-Temper welded their awesome Olympic winning steel frames but by then the steel frame era had run its course. Too bad, that was some incredible material. Too bad Nelson Vales ruined his racing career shoving white stuff up his nose after those Olympic wins, dude had some legs.

I did not know True Temper built bicycle frames? True Temper was one of Schwinn's vendor's for frame tubing.

John

 

[AS-1]

butted tubing,

The Schwinn Cimarron (Greenville, late 80's) butted the head tube ends of the top and down tubes. The other ends were lugged. John knows a lot about the actual process and saw it being worked. I hope he adds that info here. It makes a pretty joint and in the case of the Cimarron, it's a bit unique

 

[Schwinn Sales West]

The Schwinn Cimarron (Greenville, late 80's) butted the head tube ends of the top and down tubes. The other ends were lugged. John knows a lot about the actual process and saw it being worked. I hope he adds that info here. It makes a pretty joint and in the case of the Cimarron, it's a bit unique

I don't have any Cimarron specific stuff.

But consider this. When we talk about quality bicycle frames that are built with Double Butted tubing, it's only the top and down tubes that were "double butted". The seat tube is only a "single butted tube". The thicker end is at the bottom bracket, and the thinner end is to fit the seat post diameter. Forks, chain stays, seat stays on the better frames were all tapered tubes. Thicker at the fork ends, and thinner at the large ends.

I never had the chance to visit the Greenville factory. My boss, and everyday carpool buddy Dave Staub visited Greenville twice and relayed to me his observations. I did get a chance to visit the Chicago Factory in the late 1950's, the Waterford Cycles factory, and the CCI Kestrel Factory. One of the coolest factories I visited was the Skyway wheel factory in Redding, CA. This is where they made the plastic and carbon fiber Tuff Wheels for the BMX era. The dies come together, they squirt in molten plastic, and out pops a "smoking hot" BMX wheel like magic.

John

 

[AS-1]

I don't have any Cimarron specific stuff.

But consider this. When we talk about quality bicycle frames that are built with Double Butted tubing, it's only the top and down tubes that were "double butted". The seat tube is only a "single butted tube". The thicker end is at the bottom bracket, and the thinner end is to fit the seat post diameter. Forks, chain stays, seat stays on the better frames were all tapered tubes. Thicker at the fork ends, and thinner at the large ends.

I never had the chance to visit the Greenville factory. My boss, and everyday carpool buddy Dave Staub visited Greenville twice and relayed to me his observations. I did get a chance to visit the Chicago Factory in the late 1950's, the Waterford Cycles factory, and the CCI Kestrel Factory. One of the coolest factories I visited was the Skyway wheel factory in Redding, CA. This is where they made the plastic and carbon fiber Tuff Wheels for the BMX era. The dies come together, they squirt in molten plastic, and out pops a "smoking hot" BMX wheel like magic.

John

I guess the "modern" steel framed bike has been around for +/- 150 years. Isn't it cool how far we've come but how some things are really just about the same. Those Ol' Dudes were pretty sharp.