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How does a lugged steel frame compared to weld?

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88K views 134 replies 38 participants last post by  froze  
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#1 ·
I've always wonder about this. See I have a '93 Casati and people tell me it's Columbus steel, and to be more specific, it's probably 4130 thin tube chromoly steel. But I notice that the joints are not welded at the bottom bracket area, but it's lugged.

And I see that custom bike builders today like to build frames that use lugs, and the bike style they build are similar to those classic Italian 80s & 90s steel frame. Aside, from nostalgia and the desire to ride something classic, is there an advantage or disadvantage of any sort in using lugs over welding? I would imagine quality lugs are more expensive to make than to just weld it?

I don't see the big names making lugged frames, only the custom ones. So I can only assume that lugged frames are either expensive to make or not as stiff or both? Would like to know a little more info.
 
#2 ·
Welding of frames became popular with MTB's in the late 80's. Welding has a lower cost than lugs and brazing and tubesets were made for tig welding. There's nothing wrong with either method, both will produce a strong joint, a welded frame can be lighter, but it all comes down to the tubeset used and the construction. I have three steel frames, a welded Pegoretti, lugged Merckx, and a fillet brazed custom. All three have excellent rides.

If you're a steel fan, check out R&A Cycles, they have a large inventory of NOS steel frames.
 
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#3 ·
Lugged construction limits the geometries a bit. You can build a frame with either construction type and still get the same/similar ride qualities. It can be welded, fillet brazed, or brazed with lugs. Most custom builders do lugged or fillet brazed or welded. I suggest you do a little more looking around, as there is a wealth of information around about the various construction types.

All tubing used in the construction of steel bikes (other than stainless) is a type of 4130 chromoly. 4130 is a general class of steels, based on the content of the alloying elements. The different types of alloys allow for higher strengths, allowing for thinner tubing and incrementally lighter frames in the right hands.
 
#8 ·
Cbookman said:
All tubing used in the construction of steel bikes (other than stainless) is a type of 4130 chromoly. 4130 is a general class of steels, based on the content of the alloying elements. The different types of alloys allow for higher strengths, allowing for thinner tubing and incrementally lighter frames in the right hands.
Click to expand...
This is simply not true. 4130 is a very specific alloy of steel, different from even 4140 and other chrome-moly steels. Reynolds 531 and 753 steels are manga-moly. And none of the air hardening steels (Ox, 853, S3, 631), nor the micro alloyed niobium or Nivachrom is chromoly.

Lugs allow generally lighter tubing and lower temperatures to have less impact on heat treated tubing. Generally, a lugged frame of fairly normal gauge tubing will be slightly lighter than the equivalent frame of TIG'd steel. It is a more involved building process than TIG.

I think lugs and fillet brazing are more elegant ways to join steel.
 
D
#5 ·
I've got one of each - an English built Bob Jackson, lugged, full custom geo in Reynolds 853 OS and a welded steel Gunnar - stock geo, tubing unknown.

The Gunnar is a softer, easier ride, which is hardly surprising, but it still handles very well. Have never bothered to weigh either, and the Gunnar tends to have 'stuff' hanging off it whereas the BJ is more 'delusionally' rigged.

Lugs can be 'fudged' a little - mine had the top tube raised one cm at the front and dropped one cm at its rear end. Which caused no eyebrow raising at BJ's.

Ultimately, go with a builder you like, who specialises in whichever technique you fancy. Despite fashion, I still have the odd urge for a Waterford RS33 in their lightest welded steel - painted black with minimal decals, it would look like a plastic frame in the right light ;). Getting your geometry right comes first, followed by your aesthetics needs.

Good luck with your choices

D
 
#11 ·
Infidels!

The only thing you need to know is that lugged is BALLLLLLLERRRRRR
 
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#12 ·
Bike frames used to be lugged because of the technology of the era. Tubesets were thin, and difficult to weld without compromising the heat treatment of the tube at the weld zone. It was easier to control the quality of the frame, and the builder made less scrap frames by using lugs and brazing the tubes together. The lug was a neccessity.

Modern tubesets, and modern tig welders offer more consistency than before, and frames can be produced more cost effectively by welding them together nowadays. You just put the tubeset in a frame jig, and hit the "go" button on the robotic welder, and a frame is welded when you come back from your coffee break. Custom builders can weld with much more reliabiltiy than before, with the improvements in modern tig welders too.
Some of the special steel alloys still require low-heat brazing to manufacture them, to insure the strength and quality of the tubeset. So, the lugs still have a legit purpose for some frames. Builders can create some awesome looking lugs these days with the popularity of waterjet cutting, and it creates a very distinctive look on the finished bike that sets it apart from all the clone looking welded frames. Fillet brazing looks sweet, because the frame looks naked, and the joints of the frame look seamless.

I still drool over a nice, Columbus SLX tubed frame, with chromed lugs and chainstays. My 1st couple of bikes were Italian Columbus SL and SLX frames, and I loved them.
 
#13 ·
+1......... I still drool over old steel De Rosas, Olmos, Benottos and of course, Nagos (to name a few) with their well-crafted lug work and superb tubing. Even the Japanese bike companies and many American companies (Paramount, Medici and Specialized come to mind) had some bikes with well-designed, sculpted lugwork. All were absolutely gorgeous no matter how you define beauty. The attention to detail that was given to those old steeds was second to none. While I love my modern carbon and aluminum bikes, they don't evoke the same feelings as those vintage steel racers from decades ago.
 
C
#14 ·
Well, I just had a chat with a customer about this.
I think it is less about construction method than it is about geometry, tube selection and build quality.
But generally, lugs are a tad heavier, and (barely) stronger, and brazed can be built a bit lighter.
Looks are a personal thing...I really dig the new Fondriest we just got in, but the Alchemy steel project we are working on will be brazed, for light weight raciness ;)
Image
 
#35 ·
CippoForLife said:
I really dig the new Fondriest we just got in, but the Alchemy steel project we are working on will be brazed, for light weight raciness ;)
Image
Click to expand...
Is that from the new Fondriest company? I never saw a lugged frame from the original Fondriest. Man, that is nice looking! What steel and how much? Paint options?
 
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#20 ·
I love the look of lugs, I'm a sucker for lugs, therefore I really like lugs.

I agree with Tom as well at: Spectrum Cycles | Materials

But this is more detailed, and if you read far enough it was proven at the University of Davis that lug constructed bikes were stronger then welded...universities can sometimes have their heads up their arses! But here's the site: A
 
#29 ·
While we are on the subject, has anyone here ever dealt with Rivendell Bicycle Works ?........I'm aware of Grant's history with Bridgestone, etc. but was wondering more about customer service/satisfaction.........Not that I could afford one at the moment, and I am certainly considering alot of different bikes, but I've always been curious about Riv bikes.........
 
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#30 ·
Rivendell is local, and Grant has lots of fans around here. Although I've never owned one, I've never heard anything but good things about the quality of Rivendell products and customer service. I'm sure there are dissatisfied customers somewhere, though; you can't please everybody. Grant is opinionated and gets flack for some of his opinions, but he usually has persuasive arguments to defend his points of view.
 
#32 ·
I have a friend who weighs 240 pounds of muscle. Back in the 80's he bought a Vitus AL and broke 2 of those frames in 2 or 3 years, then he bought a Klien and broke 2 of those within 4 years, then a Cannondale and broke broke 1 of those in 5 years. Then he decided to try steel so he bought a Rivendell. My friend explained his weight and he had broke those bikes frames and he wanted to tour across the US on a bike. Grant listened, had a Rivendell built and after 9 years of touring every year for 3 to 4 months at a time the bike is still going strong. 9 years is the longest my friend ever had a bike last! That bike is an actual Rivendell not a Atlantis or whatever other names they carry.

I almost bought an Atlantis 4 years ago but decided instead on a Mercian because they had a lot more options I could have done to the frame that Grant couldn't do; plus I was taking a trip to England that year anyway so went to Derby and they custom measured me and built it and sent to my home 3 months later. Mercian builds their frames the real old school way, they heat the frame tubes in hearths before silver brazing them supposedly maintains the steels strength better along the whole tube. I don't much about that stuff but it sounded cool!!

I think there were lots of old school production bikes made in the late 70's and through the 80's that are every equal to a Rivendell frame or probably even the Mercian. I bought a 85 Schwinn LeTour Luxe for $100 used with only 250 miles on it in 2010 and that bike is every much the equal to the Mercian except the Schwinn weighs 3 pounds more, but when loaded for touring the Schwinn rides a bit better. Schwinn made a Voyager too that was fantastic; Trek 620 and 720 were fantastic; Bridgestone RB1 (a Grant design), Miyata 1000 and others were great bikes that one could find use today for a lot less money then Rivendell or Mercian, and those bikes were very well known reliable world travelers.
 
#34 ·
cry lion,

That's a lot of information. Here's what I attempted to reduce it to:

The "stupidity" here is that 853 and Ox are advertised as "air hardening" as are other steels, like A series. But you are saying that True Temper and Reynolds are actually selling a steel well known as an oil hardening steel, and labeling it "air hardening". Is that correct?

A9 is a medium carbon steel that can be used without tempering. Does that also shatter like glass?

I also have a knife made of A2. Did the companies that make such knives do something wrong using A2 for a cutting blade?

Where can I also view the alloys of 853 and Ox Plat? Or read where Reynolds and True Temper refer to 4340?

Can we successfully sue both companies for claiming to have modified an aerospace steel grade, when they are secretly selling common 4340 oil quenching steel?
 
#36 · (Edited)
Lets just say they have a different definition of what air hardening really is.
As you plobably know A2 stands for Air2 and all O-series oil, W-series water, but this all depends on thickness, preferably you cool all steels as aggressive as possible without it cracking in the process. So A, W, O are only "guidelines" and those definitions were implemented at least 50 years ago.

Many steels can be used without tempering. It depends on carbon content, quench method, 'alloy content, what alloying elements and hardenability.

If you were to take a steel like 1084 or something similar thats regarded as a waterhardening steel because you would need to get under the Ms (where martensite formations starts) line within 7 or 8 seconds or so, sure you could quench in oil, but then you would not get full hardness, forced air could do that too, now it goes even softer "as quenched". Now maybe you can get away without tempering it, maybe. Suboptimal yes, in many ways but yeah you can do it. Doesn't mean you should though, it means there are better alternatives for this type of use and you should use that instead.

A2 would make a very good blade, very tough (only compared to most other steels used in knives, including all hardenable stainless steels) and can reach 60hrc, whats not to like. If you have a knife made out of this steel it was tempered after hardening, probably twice, so its not brittle as glass any longer.

But making a bike out of A2, thats well, I wont say impossible but its kind of stupid, first its not even weldable at room temp, then after welding at extremely elevated temperature it would need normalizing, austenizing, and tempering (twice). And the end result would be worse than 4340/4130 because those 2 are much tougher (and weaker), I don't know but possibly 10 times as tough and half only as strong, just as stiff. Not a good tradeoff.

A9 contains 0.5% C, (this is very low carbon content for hardenable steels) 0.5% Mn, 0.95–1.15% Si, 4.75–5.00% Cr, 1.25–1.75% Ni, 1.3–1.8% Mo, 0.8–1.4% V

So its almost weldable at room temp had it not been for the extremely high alloying content.. You could probably get away with not tempering it (for a comparatively really shitty and very expensive result no matter what it was supposed to do in the end), but what a waste when you can insted just ditch the 4% Cr, all Si, most of the Mo, and all but 0.2% V (for grain refinement), and have something more suitable for a bike that is.

What would you sue them for? They are selling a product, tubes which they have welded and butted and whatever they do, they can call it whatever they want. Doesn't change the fact though. Do you know what it takes to develop custom non standardized alloys? I do.

And I'd say the chance is very slim this is the case, its much easier to just go with the best you can find and then maybe add 1 element which you know wont do anything but good, for example Vanadium or Niobium, no risk involved at all but it will be better, and more expensive.
 
#37 ·
When you are making something out of steel, you never use more expensive steel than necessary, the things that cost money is alloying content and the heat treatment.

Lets say you need a tool that only needs be hard (resist compression) lets say 40hrc, there are many ways to get there, at least 500 alloys will get there and you can heat treat them all in several different ways to get there, however this does not say anything about stain resistance, toughness, creep resistance etc etc.

Selecting the right steel for the application is the game, if you need medium stain resistance and only 40hrc there are many steel to choose from, usually you choose the toughest one (lowest carbon content) and one that only has enough Cr to make it somewhat resistant to rust. Done, best choice. In this case you are aiming for a steel that is 45hrc as quenched (the most aggressive quench) and then taken it down to 40 with the tempering, this will give you a much better product than a steel that is 60hrc quenched which you need to temper down to 40, its rediculous to do that, and its cost much more money, and the HT is much more complex. AND its not even needed, its actually really stupid. AND will give you a worse over all product in the end, you just don't do it.

If you need 2hrc more you choose a higher alloyed steel and HT that as good as you can, or push the limits (but this takes extensive knowledge and you can not mass produce these parts in a very rapid pace) with the one you have. If you need 2 hrc lower, then you choose a lower carbon lower alloyed steel and save money and energy while HT'ing it. Thats the wiggle room. No one in the entire world would choose something thats designed for 60hrc and use it at 40 because you can get a much tougher (higher performing) steel if you only need 40 to being with. The higher the carbon content the more brittle, the higher the alloying content the more brittle. And thats it. This is how it works.

At a certain temperature all steels becomes brittle. High alloys steel might have this point at 0C and low alloys ones at -40C but there always somewhere where the steel becomes significally more berittle so low carbon content is highest priority for almost everything. Up the carbon = more brittle (and extreme brittleness starts at a higher temp), up the alloys over a certain point (element dependent) = more brittle (and extreme brittleness starts at a higher temp).

There is no sane reason why one would choose any of the A-series of steels for a frame, they are all very inappropriate for this application, and expensive both in purchase and HT. However 41/43-series, yes sir, very good and very appropriate, very cheap too, high workabilty/plastic deformation due to low carbon and alloying content, and weldable!

I strongly suggest you start working on those books, they contain this type of info and much much more. And I wouldn't have to write all this crap saving me lots of time. Win-win!
 
#40 ·
This has been extremely enlightening, absolutely the most knowledgeable series of posts I've ever read, thanks for sharing your knowledge with us. It may not be directly related to lugs but I thought that was ok, so lets try to redirect back to lugs.

So if you put all this info together, would assembling steel bikes be better using lugs or welding? I know some steels either cannot be lugged and must be welded to gain strength...at least that's what we're told. What is your opinion on using lugs?

Also a fun question, is your forum handle Cryon stand for Cryogenic's? If so, I assume you're involved in cryo processing of steel. How would this sort of treatment if done to steel used in a bike effect the durability? and would it enable lighter steel bikes to be made?
 
7
#41 ·
My custom road bike was built lugless. Got it in 1998, in England. The builder has to be exceptionally skillful to braze the tubes w/o lugs. This configuration offers a slight weight reduction, but the big advantage is that the frame is more lively. It absorbs road shock better.

Stiffness at the crank is largely a function of the bottom bracket, so having lugs has little effect on the power transmission. I'm an old guy, so I like the soft ride and didn't want to get a Titanium frame. My tubing set is Columbus EL OS. Superb metallurgy. Maker was Charles Roberts of London.
 
#45 ·
I am far from an expert in frame building so I'm not saying something I think I know a lot about! But I read somewhere that lug constructed frames vs filet brazed frames of equal dimensions and tube material like 531c for example, the weight is the same, because they have to use thicker butts in a filet brazed tubeset so the frame will be strong enough at the unions, vs using thinner butts and joining them with lugs. But the lugs makes for a stronger frame due to lugs being one piece. Any thoughts on this?

By the way, an older guy too, 58 years old to be exact, all I own is steel lugged bikes but my next new bike will be a TI frame because they absorb road shock better the CF or steel, and it plenty light enough, plus TI is almost indestructible both in impact and rust or corrosion...except the CF fork is not! but I would rather replace a fork then a frame in the unlikely event of an accident.
 
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#43 ·
Crylion,
I gotta say I'm liking your divulge of info. I've only had 1 year of college general chemistry (a requirement for me to take), and while I don't understand know most of the types of metal & their associated manipulation methods, I do understand most of what you said conceptually. All your info on atomic structure, alloying, heating & cooling, expansion... all do make sense to me!

Sadly I'm in computer science now!
 
#48 ·
I'm glad you liked and understood it. To understand most things you really have to go down to the deepest level, to really understand the mechanisms at work, then its all easy. I try to explain things so even 5 year olds understand. The mechanisms are not hard to understand if someone can distill and explain them properly. Now you're a bit smarter and know quite a lot (at least more than 99.99% of all people) about high performance steel and it heat treatment, because the high performance part usually comes from the heat treatment, not the material per se. Well to an extent.

froze said:
This has been extremely enlightening, absolutely the most knowledgeable series of posts I've ever read, thanks for sharing your knowledge with us. It may not be directly related to lugs but I thought that was ok, so lets try to redirect back to lugs.

So if you put all this info together, would assembling steel bikes be better using lugs or welding? I know some steels either cannot be lugged and must be welded to gain strength...at least that's what we're told. What is your opinion on using lugs?

Also a fun question, is your forum handle Cryon stand for Cryogenic's? If so, I assume you're involved in cryo processing of steel. How would this sort of treatment if done to steel used in a bike effect the durability? and would it enable lighter steel bikes to be made?
Click to expand...
Personally lugs makes sense to me, its thick at the joints and thin in the middle of the tube. But I'm no weight weenie, I'm more like a durability weenie, but I don't like stuff that is heavy but offer no extra durability/strength/stiffness whatsoever, that just bad engineering and bad design imo.

However like most things in life there is a difference between a conceptual idea and the actual manufactured part/frame. I mean the execution of the concept, or the skill and knowledge of the maker if you like. I have a feeling this is what it all boils down to. A really good welder/frame builder can probably TIG weld a stronger and more durable frame than 90% of all lugged and fillet brazed ones out there. If I'm getting a custom steel frame my least favorite option would be TIG welded (too abrupt interface between the tubes imo), followed by fillet brazed and the most desired would be lugged, if the lugging is good that is, otherwise the order will be different of course.

No i don't work with crying of steel but I know "enough" about it. Basically cry works like this: In high alloyed steel the martensite finish point MS (the temperature when all steel is turned into martensite) is way below 0 deg C like -150C or similar, then you have to freeze the steel to get a full transformation, otherwise you will something called retained austenite in the steel, and this in not especially strong nor hard.

Usually with high alloyed steel like hss and stainless tool steels you harden them at very high temp, and high temp automatically gives you lots and lots of retained austenite, like 30-40% in some cases. Most high alloyed steels require a high temperature (550+ C degrees) tempering to convert the retained austenite to hard carbides and untempered martensite. and you need to do it several times. At least twice. Long soak time too.

So for most high alloyed steels cryo doesn't matter since they are going to be tempered in a high temperature anyway afterwards.

Also a cryo treatment needs to be done pretty much immediately when the steel has reached room temperature after hardening otherwise the phases stabilize and then it doesn't matter anyway since you can't affect it anymore. Cryo also needs be done immediately after the first tempering cycle. After that treatment you have a substantially better steel, since you can harden it much harder from the get go (like 3 hrc points, which would only be wasted if the result would be 10% more retained austenite in the end product), and temper it in a higher temperature (but lower than 550 degrees) so it gets tougher (you release more internal stress).

Basically you can either get harder and stronger steel, or tougher steel with no negative effects, in the order of 3 hrc both ways. But only some steels can benefit from this treatment.

However some rifle barrels are cryoed, long time after production too, and users report double and better life out of those. But this in only anecdotal at best. Good rifle barrels are usually made from 4130. However rifle barrels are not hardened at all, instead they are stress relieved and annealed in many cycles throughout production to eliminate any stress or tension that might warp or slightly bend the barrel when it heats up with use.
I think it has some effect on barrel life. Why it works is not currently known, scientifically.
This is a material that shouldn't be affected by this treatment whatsoever, but still many people report benefits.

But on a bike? Well I'm not spending a dime on it at least so thats my stance on cryo for bikes, the result if any would be microscopic.



I see that I wrote that the eutectic point for a carbon/iron material is 0.73%, this is wrong, its of course 0.83%, sorry. I was probaably a little drunk or something when I wrote that :D

Also I would like to thank those that enjoyed the read and gave me good feedback.
 
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#44 ·
And now that I examined my bike (1993 Casati with Columbus steel) closer, due to this thread,
it appears that my bike has braze at 2 points
1) the head tube aread
2) where the seat tube, top tube, & seat stays meet

It has lugs at 1 point: where the down tube & seat tube meet (at the bottom bracket shell area).

So it appears my bike is not fully lugged, but it's a combo of lugs and braze. It's a piece of art. Shame that it was crashed and had to be repaired with a plate :((
 
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