whaaaa??? prior to Reynolds 501 Cr-Mo was "straight pipe"?
Is this your spirit guide talking again
You better tell him to check with Columbus, Tange, Ishiwata, Miyata, Vitus, etc.
And then have him check with Peugeot about how much 501 tubing was TiG welded...

Concur! Thanks T-Mar!

""Prior to that CrMo was straight pipe (lugs not only join tubes but are exterior butting;"

That second sentence has been edited.

Accles & Pollock was making seamless cold-drawn double-butted chromium-molybdenum tubing in the early 1930s.

I don't see what relationship Reynolds 501 has with the introduction of TIG welding. 501 was introduced circa 1983 and all the early 501 frames that I'm aware of were lugged, with the notable excpetion of Peugeot's internally brazed model.

Likewise, the ecomonics of TIG welding itself were secondary. The prime reason for the for the adoption of TIG welding was the flexibility it provides in frame design, when not restricted by lugs. Developing lugs is very expensive and eliminating them provides great flexibility in both angles and tubing diameter and shapes.

The initial move to TIG was driven by ATBs. Originally, the slacker fangles favoured on ATBs forced many manufacturers to employ laborious and costly fillet brazing until appropriate lugs were developed. Then, in the mid 1980s, Rocky Mountain popularized the sloping top tube with their Blizzard model. The advantages of the extra crotch clearance was not lost on manufacturers and sloping top tubes became a standard ATB feature. However, rather than develop new lugs, TIG welding was employed to accommodate the non-standard angles. Manufacturers like Ritchey and Fisher also realized that, without the constraints of lugs, they could do things like laterally stiffen the bottom bracket by ovalizing the bottom of the seat tube.

Meanwhile, road bicycles primarily hung onto their lugs. The move to TIG welding on road frames occured as a result of another non-strandard design, the introduction of oversize steel tubing to increase ridgidity without increasing weight. In the very late 1980s, steel's reputation was begining to suffer at the hands of aluminum, carbon fibre and titanium, which were generally considered to be more advanced. Steel manufacturers fought back and one method was by taking the lesson learned from Kein's and Cannondale's oversized tubes. Rather than developing oversized lugs, TIG welding was employed, as most manufacturer's had experience from manufacturing ATB frames. The first major move came in 1990 with the introduction of the Diamnod Back's Expert TG and Master TG.

TIG certainly has added advantages in cost and weight but the prime motivator in its adoption was non-standard frame design, both in terms of geometry and tubing. It's outside my area of expertise but I wouldn't be at all surprised if the the original employment of TIG welding in bicycle frames dates to the late 1970s BMX explosion. Certainly, they had the rationale with their non-standard angles and gusseting. However, if so, there appears to be a rather large gap between its use there and it's adoption for ATBs and later road bicycles. Perhaps a forum member knowledgeable in BMX could enlighten us?

T-Mar, wow!

Have you ever considered writing a book on bicycle technical history, at least that to which you've had inside exposure? You seem to have the subject pretty well covered, going by your extremely knowledgable and detailed contributions to threads like this.

Thxs for the compliment. The subject has been raised before. I've considered it and have a few projects which I'm considering but will probably not come to fruitioin. So far, I've been content supplying technical and historical information for other people's books and websites (both credit and uncredited) and, of course, posting here.

Yes, I tried to edit out that sentence, right after I posted it, but you were too fast!

Good observation that cromo frames started appearing in just-above-bottom-level bikes in the 80's. However, they were about as heavy as bottom rank bikes, so the advantage seems questionable. Take something with the same strength-to-weight ratio as cheap stuff, and use the same amount of it. What's the result? I think it's something that's stronger than a cheap frame, but in general, the cheap frame was strong enough. So I think most of what it gives you is bragging rights.

T-Mar, please write a book! It's great to read this stuff.

This is what happens when one presumes too much. First, I have always been intrigued with my 1985 Peugeot PH 501. From the Peugeot catalog.

Until now lugless racing bicycles made with high quality lightweight tubing were produced on by a few very talented craftsman and priced way beyond the budget of most riders. Once again Peugeot has been the innovator making the first lugless bicycle using Reynolds 501 chromoly tubing. The result is out lightweight and affordable PH 501.

While I am highly skeptical of catalog hype, the bike was relatively light (23 lbs with pedals) and lugless. Since 501 was Reynolds butted version of their 500 CrMo it made sense that a lugless butted frame could be made as well as a lugged frame, as the lugs work as external butting. The mistaken post was meant to say the prior to 501, "Reynolds" CrMo frames were plain gauge or "straight pipe", instead I made the blanket statement that all bike frames prior to 501 were straight pipe, which was obviously wrong; but you quoted me before I could edit that out; you are very fast!

Anyway my post should have been Peugeot specific, but it certainly resulted in a plethora of information from T-Mar; not the result I was hoping for, but it turned out not to be a total loss.

Maybe we should have a sticky with T-Mar's collected posts.

Junkers also built corrugated metal aircraft with metal frames in the First War (as early as 1915), but I doubt they were Cro Mo or anything like that. I think they were "electrical" steel or the like at first, then switched to duralum.

Tom, I'm going to have to respectfully disagree. Many tubing manufacturers offered seamed, butted, CrMo tubesets that used the same wall thickness and butt lengths as their seamless tubesets, resulting in comparable weights. The introductions of these seamed tubesets, in conjunction with component technology trickle down, allowed bicycle manufacturers to offer sub $300 bicycles in the mid-1980s that weighed around 25 lbs.

That's about a 3lb weight reduction with only a doubling of price over what was being offered a decade earlier. While some of it can be attributed to the components, notably the widespread adoption of aluminum rims and aluminum cotterless cranks, the deduction in frame weight is not inconsequenttial. Entry level frames with seamed, butted CrMo main tubes and hi-tensile stays were running around 5 lbs in a 23" size.

Making the post Peugeot specific would not have precluded any issue, as the Peugeot PH501 was not TIG welded as you suggest. These frames were internally brazed using doughnuts of brazing material that were inserted into the ends of the mitred tubes. When heated using a ring torch, the brazing material material reflowed and some was sucked through to the outside of the tube by capillary action. The resulting joint had a large fillet on the inside with a smaller fillet on the outside. One of the major benefits of this method was that it allowed for visual inspection of joint quality. The presence of the fillet on the outside indicated the quality of the reflow via the size of the fillet and the amount and size of voids.

Here's an illustration from an early eighties Peugeot catalog showing the type of lugless "internally brazed" joint T-Mar refers to.

Of course, Peugeot managed to ignore the mass produced and affordable Lambert/Viscount lugless chrome-moly frames that were on the market a full decade before the PH 501...

The protoype Junkers all-metal aircraft reportedly used frames constructed from steel angle channel and I-beams. While I've seen nothing on the alloy designation, I suspect it was similar to what Fokker was using. The production model that served in the Great War used primarily aluminum tubing for the frame and a corrugated aluminum skin, though they did use a 5mm "chrome-nickel" steel sheet on the forward fusealge for engine and crew protection. I've seen the sole surving sample which resides in the National Aviation Museum in Ottawa.

You know as wrong as I was about all this, I never would have known the real story without posting. While I don't necessarily want to air my ignorance in this area, I certainly learned a lot. I don't plan on making a habit of this, but the "internally brazed" joint was something I actually saw in "How It's Made" one time, I just didn't know it was what Peugeot used also.

As apoint of interest, that How It's Made segment was actually filmed at a Peugeot manufacturing facility. It's the Procycle factory in Saint-Georges Quebec. Procycle had been manufacturing internally brazed Peugeot for the Canadian market since 1988, then took over the internally brazed manufacturing for the USA market in 1990. By then the process had been named DBS (Direct Brazing System). The video was made just about the time that Procycle's Peugeot license would have expired, circa 2000/2001. Consequently, the video features CCM bicycles, a brand that Procycle bought in 1983. Regardless, those are the actual manufacturing processes that would have been used to build many of the North American Peugeot.

You are a bike frame knowledge god!

I love that show!
and have learned so much about how hockey sticks, skates, gloves and snow-blowers are made...Oh, Canada!

really, I do love that show!

I am relieved this thread has not dug up the tired and misleading old debate between Columbus/CrMo and Reynolds 531/MnMo fans. (Of course my 531-tubed Capo is "soft" and my Columbus tre tubi Bianchi is "stiff," but look at the difference in frame geometry, reflecting a 20-year evolution in European road surfaces and road bicycle frame design philosophy.)

American Eagle bikes were built by Kawamura circa 1970, with the top-of-the-line Semi-Pro and Road Compe models using an Ishiwata double-butted CrMo with extremely disappointing ride quality (heavy and soft -- been there, done that, even had a Nishiki t-shirt). Japanese tubing quality improved markedly during the 1970s, such that the higher-end Nishikis were world class by the end of the decade.

Okay, so, I read the comments related to my additional questions connected to the original posters questions. I agree with T-Mar's remarks to Tom's comments. 4130 Chromoly (aka bike tube chromoly) is 1.75 times stronger than 1020 high tensile (aka bike tube hi-ten). So, in theory, a frame made from chromoly could end up being 60% lighter. Chances are though, the difference is less. For one, standardized tube diameters and standardized tube wall thicknesses mean that you probably couldn't get EXACTLY the tubing dimensions that would be ideal. For instance, your calculations may say that the perfect seat tube (with a chosen wall thickness of .08") would have a diameter of .83467 inches. Well, .83467 isn't standard, so you would probably be forced to round up to the nearest standard diameter, say .875". Also, a lot of frames used chromoly tubing for the main tubes (which have approximately 1" diameter) but hi-ten stays (where, because of the comparatively smaller cross-sectional area of the tube, the weight savings would be more diminished, and the cost not worth the weight savings). I would like to know a comparative weight of a 23" size frame made with hi-ten tubing, anyone know? Plus, I have a KHS Classic bike, made with Tange #5 tubing (which I believe to be seamless) that has components with a 1981 manufacturing date. I assume that it was fairly "entry level" for it's era, with it's components being fairly closely matched to my 1977 Schwinn LeTour II (definitely near entry level specimen for it's day). So, I question whether the ability to create seamed chromoly tubesets was the driving factor for the reasoning as to why chromoly tubing became so affordable and widespread in the eighties. It seems to me, since Tange seamed chromoly tubing (like Tange 1000) showed up AFTER it's other tubing offerings (like Tange #3, which is quite similar in size/strength as Tange 1000, but seamless). So seamed chromoly tubing did provide lower pricing, but it did so after seamed chromoly tubing had already shown up. Any arguments to refute my claims (more like guesses than claims really)?

Be careful, guesses can really get you into trouble around here