Bam42685

Why don't modern bikes have them? I'm not talking about carbon fiber or other super lightweights, but the few modern steel bikes I've come accross are just welded like old huffys. Is there something new and different with modern welding that makes it superior to lugs, did they go out of style, or am I just seeing the wrong frames?

cyclotoine

Yes welding is lighter and faster and cheeper and stronger, you can produce a wider range of frame geometries and used a variety of tube shapes.

people will argue that it is not NECESSARILY stronger and they may be correct but unless you file your lugs very thin and do a very good job brazing it will be weaker in theory because of the stress points on the lugs, of course that doesn't tend to matter too much.

the important parts are lighter weight, cheeper and faster to make.

StanSeven

Yes. I got an 853 Waterford about 18 years ago with lugs. I didn't know until a couple years later 853 is stronger with welds than with lugs. Waterford just used lugs for tradition.

noglider 

It's because there was some breakthrough that made welding good for bikes. I don't remember the breakthrough. It's a method of welding, though.

dokydoky

It is worth noting that lugs still do have their applications in carbon fiber. Colnago, for example produces lugged carbon frames in addition to using monocoque construction.

TIG (Tungsten inert gas) welding, by the way, is the technique used on most contemporary production steel frames, but I don't know much more than that.

andy e

don't lugs make replacing a damaged tube more feasible?

johnknappcc

You see the options list for a Waterford? Holy, *#@!*#, just for lugs!!!! BTW, I like lugs. But yeah, if it can be done cheaper, it will be done cheaper.

tatfiend 

Theoretically yes though to get the original tube out of lugs normallly will require unbrazing at least two lugs so the new tube can be inserted w/o bending other tubes I believe. A job for a custom frame maker with a frame alignment jig which means it is expensive if it is to be done correctly. Not too many frames are normally worth the expense.

I suspect not much easier than cutting out a damaged welded in tube on a current steel frame and welding in a replacement for the original if done by a frame maker who knows what he is doing. IIRC some of the best custom steel frames used fillet brazing rather than lugs even during the time when most frames were lugged and brazed construction. A lot of pretty horrible frames were lugged construction too.

BTW I do like the looks of lugged frames and just bought a Steelwool Tweed frame which is lugged except for the bottom bracket area.

unworthy1

TiG welding combined with the development of steel alloy tubes (like Reynolds 853) that are much less prone to damage caused by the higher and more concentrated heat of welding. Lugless construction was always an option in olden times (see fillet-brazed), but required more skillful brazers than lugged construction did. Now that there has been a generation of TiG welders in Taiwan becoming highly skilled at mass producing aluminum frames, and that skill has been passed on to PRC Chinese welders, the only people using lugs (still available, BTW) are artisan builders and the occasional mass-produced "experimentals". Lugs are not for Giant factories and robots, and the highest output/highest margins they demand.
I'm not a frame builder, but I'd guess that any brazed frame (lugged or fillet-brazed) would be more repairable than a welded frame: you can heat the bronze or silver alloy and "un-glue" it, but a weld is a weld.

cudak888 

What happened to lugs?

Fuji Connoisseur
De Rosa Primato
Ciocc Mod. San Cristobal & Ciocc Mod. Replica

-Kurt

Mike Mills

I think the change happened over time in a step-wise fashion.

Aluminum frames came on the scene. At first, they were lugged just like steel (ALAN, 1972). Then titanium came on - TIG (?) welded. Then aluminum went welded, again TIG welding. Once welding gained market acceptance from the consumer and was the production process on the floor in the bike factories, people began to weld steel, too. Welding a steel frame was possible ($) in part because you can TIG weld without the problems of old-fashioned arc welding (embrittlement, contamination).

Well, that's the way it seemed from my perspective. The industry insiders will know better than I.

Scooper

+1

The development of air-hardening steels like 853, S3, and OX Platinum have made the tubing far less susceptable to weakening in the HAZ (heat affected zone) at the TIG welded tubing joints than older alloys. In fact, air-hardening steels actually gain strength from the heat in the welding process. Brazing, whether fillet brazing or brazed lugs, is done at much lower temperatures than welding, so until the air-hardening alloys were developed, brazing was the preferred joining method; the strength of the steel wasn't compromised by the high welding temperatures in the HAZ around the tube joints where the stresses are highest.

Another advantage of TIG welding is that framebuilders aren't limited to the angles of lugs; joints can be welded at any angle.

Sixty Fiver

A high quality lugged frame is about as good as it gets and the primary reason modern frames are tig welded and not brazed is because it is cheaper, faster, and an excellent product can still be produced on a mass produced scale.

I am about to acquire a Ron Cooper lugged road frame... I expect this to be the crown jewel in my collection as I can't imagine owning a nicer built frame.

Scratcher33

The Soma Delancey and Soma Speedster are mass-produced lugged frames.

Veloria

Modern welding techniques are cheaper, but whether they are "better" is highly debatable. There are manufacturers that still make lugged steel frames, including "Dutch style" bicycles by Pashley, Gazelle, Velorbis, Batavus, and even the US Biria, and road bikes by Soma. Of course there are also bespoke and semi-bespoke options like Rivendell and ANT.

A nice article from Rivendell: "Why Lugs Are Good"

Exit.

On a vaguely related note, has anyone ever seen/heard of a lugged Ti frame? I've seen lugged carbon, but never lugged titanium...

Veloria

I have tried to research this, because I cannot stomach anything without lugs, yet I like titanium.

You probably know this better than I do, but titanium cannot be brazed as well as steel, which is why we do not see lugged Ti frames.

Having said that, have a look at this:
https://www.bgcycles.com/NAHBS08.html

Exit.

Hot damn! The lugwork on that looks amazing...too bad about the compact geometry though.

Veloria

Yes, the lugs are quite nice! I like everything except for the shape of the fork, which seems to lack elegance compared to the exquisiteness of the rest of the bike. Amazing job though, and deserving of the prize.

tcs

Lugged frames can indeed be mass produced economically, as anyone who was riding 30+ years ago can afirm.

tcs

JohnDThompson 

Automated TIG welding. Saves a lot of money and works fine.

But welded joints also create stress risers, and poorly welded joints can undercut the tubing making it much weaker.

Picchio Special

There are more options for lugged frames now than there have been for a long time, maybe ever (at least in the US). But it's a relatively costly niche area of production.

unterhausen

consumer acceptance of welded high $ frames was also very important in relegating lugs to mostly high end custom frames. I blame cannondale. If you look at the difference in price for someone like to build a lugged frame vs. a tig welded or fillet brazed frame, it's on the order of $150. May not sound like much, but it starts adding up.

vjp

I love beautiful hand filed lugs on many vintage and newer custom built bikes but I would take a tigged custom such as a Waterford or IF over any of the current production lugged bikes such as the Soma or Kona. They are just done for fashion sake and really are plug and play mediocrity.

vjp

Scooper

I came across this thread a while back and was so impressed by the opinions of several well-known framebuilders in the U.S., that I saved it. They make some interesting points.

******************

Froze --

Peter you’re incorrect about the heat zone being less in TIG welding. Here is a quote from Airborne Bicycles concerning what you said:

"How you weld a standard metal frame together is very important. For steel you can use lugs, TIG welding, or fillet brazing. Lugs add weight, TIG welding is good on weight but it actually melts the tubes that are being put together and creates a heat affected zone (HAZ) in the tubes that may eventually lead to a failure. The fillet brazing uses a brass-silver “glue” that gets melted in to hold the tubes together. This is actually the best system, since the tubes don’t form this HAZ, and the braze is strong enough to hold it all together. For aluminum, the most common practice is TIG welding, and most Aluminum frames will fail at the welds due to the HAZ in the tubes. Ti is also TIG welded, and has the same problems as Aluminum. However, especially in Ti 6-4 you can find frames that are welded with commercially pure Ti (CP) instead of Ti 6-4, and therefore this acts like a fillet braze”. In theory these frames are stronger since the HAZ is smaller in the Ti tubes as the CP Ti brazing material melts at a lower temperature than the 6-4 Ti tubes, so the tubes are never melted in the welding process."

Then there's the following from Rivendell:

"Methods of construction: Brazing a frame with lugs is the most time-consuming way to make a frame, and is the least popular, and generally least sought-after way. So those who do it are either fools or have good reasons. A properly designed and built lugged steel frame is the strongest and most beautiful. It ought to also be the most expensive by far, but often isn’t.

Brazed, with lugs: Pro: Makes the strongest joints. Simplifies tube replacement, so a crashed frame needn't be thrown away. Arguably the most interesting joints, since lugs are available in a variety of styles, and offer the craftsman more creative options.

Con: It's takes more time, therefore it costs more; and there's a shortage of good brazers. The lugs have to more or less match the joints, and many modern "high tech downhill" style bikes have joints that nobody makes lugs for.

TIG-welded: Pro: Fast, economical, strong, and versatile. Any tube configuration can be TIG-welded, because there are no lugs to deal with.

Con: High heat levels are concentrated at the most stressed area of the frame. Melts the underlying tube, making tube replacement impractical-to-impossible.

What is a lug? A sleeve of metal that surrounds the frame tube at the joint, strengthening the joint. Most modern frames don't have them.

2. How come? They're more expensive to build with; and from a strictly practical point of view, they're unnecessary.

3. What does a lug do? It strengthens the joint by adding material to the stressed areas, and distributes the stresses over a large area. And it adds an artistic element to the frame joint. And it allows tubes to be joined by brazing, rather than welding.

4. Why brazing rather than welding? Less heat, mainly, and one of the benefits is that the tubes themselves are not melted. So, if you crash and bend a top tube, for instance, it can be replaced and the frame made good as new.

5. Are all lugs alike? No. Some are well-designed to eliminate stresses. Others cause stresses. Some are thick, some are thin. Some fit the tubes well, others don't. Some are rather plain, some are rather ostentatious. Some are generic and available for purchase by anybody, others are proprietary and unique to one brand of bike. Some are hand-cut and one-of-a-kind. In addition, lugs can be made by any of several methods, including but not limited to investment casting, stamping and welding, die casting, and machining.

6. Is there any reason to get a lugged frame over a glued or TIG-welded frame? Well, it depends. From strictly a functional perspective, in the short-term life of a bicycle, it makes no difference whether the frame is lugged or not. And, if you plan to get a new frame every couple of years, then the long-term benefits of a lugged frame (durability and the ability to replace bent/crashed tubes) don't work for you. Likewise, if you prefer the appearance of TIG-welds, then you won't be talked into lugs, no matter what."

Then there's this from Henry James:

"Steel is the only metal that can economically and technically be used with lugs. These simple sockets at each frame tube joint reinforce the joint to improve strength, reliability and (fatigue) life. Silver or brass brazing completes the structure with minimal metallurgical damage (unlike welding which must melt the metal under essentially uncontrolled conditions). The hype put out by aluminum and titanium makers is that welding is stronger, lighter, the latest technology, and magically better. In fact, they can't use lugs and have no choice but to weld, and so they turn to hype..."

Then there's this from Kirk Frames:

"Kirk frames are made exclusively of brazed steel. I use steel because it offers many advantages, including: Ride quality, Fatigue resistance, availability of tubes with a wide variety of specs, Cost and Reparability. Steel's combination of stiffness and fatigue resistance allows smaller diameter tubing compared to titanium or aluminum. Tubing diameter is one of the main factors that influences ride quality. For example, aluminum tubing needs to be large in diameter due to its poor fatigue resistance. Titanium, on the other hand, is much more flexible than steel so it needs to be large in diameter to be stiff enough to handle properly and transfer energy. Steel tubing offers a balance of a supple ride and durability that make it a choice building material.

Brazing: Traditional brazed joints are the choice for Kirk frames. Some advantages of brazed joints are: Lower heat compared to welded joints, Smaller heat-affected zone, Allows for the use of thinner tubing and Aesthetic qualities. Brazing heats the steel to about 1,800 degrees F - just hot enough to allow the brass or silver to melt and flow into the joint. Welding, by contrast, heats the tubing to its melting point (around 3,500 degrees F). At this temperature annealing occurs in most tubing, causing a weakened area adjacent to the joint. Brazing allows for a much smaller heat-affected zone than welding. The use of lugs or fillets spreads the load over a larger area than a welded joint. This can allow the builder to use thinner tubing for a given size rider, without risking failure."

And there's Spectrum Cycles:

"Our steel frames are lugged for two reasons. Lugs are stronger and lugs are beautiful. Did we mention that lugs are stronger? Almost all mass-production steel frames produced today utilize cost-effective TIG welding to join tubes. This prompts a question: why do we still use silver soldered lugged joining? Because properly fitted and soldered lugged joints are considerably stronger than joints created any other way.

On Strength: In the late '80s, a team of scientists in the UC Davis engineering department undertook an in-depth look at the relative strengths of various steel joining techniques at the request of "Bicycle Guide" magazine. The three top frame builders associated with the three primary joining techniques were asked to supply joining samples using tubing supplied to the builders from the same mill run. Tom Ritchie provided the fillet-brazed samples, TIG-welding was done by Gary Helfrich, and the silver soldered lugged samples were done by Spectrum's Jeff Duser. The samples were fatigue tested, in some cases to failure. In most cases, the joints did not fail. More often, the tubes failed at or near the joint. The team's study involved microscopic analysis of the crystal structure of joining zones, heat effected zones and failure sites. They concluded that all three joining techniques, done properly, are clearly of sufficient strength for the purpose of bicycle frame construction. The different results obtained from the samples resulted primarily in the heat-affected areas of the tubes themselves. Not surprisingly, the tubes that were soldered turned out to be stronger than the tubes that were welded or brazed. So, what does this mean in the real world? Frames built with silver soldered lugs will last longer than those that are fillet brazed and considerably longer than those that are welded. However, for most of our customers, the real practical difference is that lugged frames hold up in crashes better, and when it becomes necessary, they are much easier to repair. On Modern Air Hardening Tubing: The latest generation of air-hardening steel tubing used by top quality welding frame builders was not available at the time of the UC Davis study. We at Spectrum expect that this tubing, when in the hands of master builders, is more reliable than the welded joints and tubes tested at UC Davis but still less strong than lugged joints.

Then let's not forget the master Richard Sachs:

"Most of the racing bikes you see today use mass-produced frames made out of carbon fiber (light, but extremely delicate), aluminum (light, but delicate and brittle to ride) and titanium (light and durable, but aesthetically crude). Because of economic reasons, the handmade lugged steel bicycle frame has become practically extinct. In the long run it's much less labor intensive to create molded carbon fiber frames or TIG welded aluminum frames than it is to join steel tubes together with a 56% silver brazing compound and a set of lugs.

Amazing how most of America's best frame builders still swear by lugs and brazing...why? Because they’re locked in the past? Refuse to grow up with the technology? Stubborn refusal to comply? NO!!! Their reputations are on the line for all the bikes they make, and if they felt welding was superior they would ALL be doing it!!!!!

Dave Kirk –

This is an interesting thread and got me to thinking (scary I know). What is the real weight difference between lugged and TIGged. It of course matters what lugs are being used (some are lighter than others) and the tubes and such.

Well I went into the vast "Kirk Frameworks center of weights and measures" and broke out the kitchen scale and came up with some interesting numbers. My idea was to weigh the frame components that differ when building a lugged versus TIG bike. They are-

Seat tube - on a lug bike it needs a seat lug of course but it doesn't need an externally butted seat tube (reinforced with a heavier wall at the top to handle the clamping duties). The TIG bike also needs a slip on clamping collar.

Bottom bracket - both types use a bb shell of course but the lugged shell has more to it so the weight differs.

Head tube - a lugged bike has....head lugs while a TIG bike does not. But the TIG bike has a heaver walled tube to deal with the loads and headset stress.

TIG welding rod versus brazing rod - a really tough one to estimate. I'm calling it a wash. I'm sure there is of course a difference but it can't amount to much. I'd guess that the brazing rod is a bit heavier and for the academic exercise of it all I'm going to research into this and find out some real numbers. But as stated above it can't amount to much as neither rod weighs much to begin with.

The measurements were taken on Reynolds 725 tubes that were the same length. The lugs are standard Richie Sachs lugs. Weight is in grams.


TIG

seat tube - 350
BB shell - 100
head tube - 175
seat tube clamp - 25

total 650


LUG

seat tube 275
long shen BB shell 140
HT and lugs 180
seat tube clamp N/A 0

total 595



Now I can here the screaming out there (sssshhh!). I fully understand that my kitchen scale is not the most accurate device known to man but it's fine for a comparison I think. I fully recognize that this is a bit crude and that the brazing rod might add a few grams the lug side of the equation but anyway you cut it the weight difference between a TIG and lug bike is minimal and might even favor the lugs bike by a few grams.

I think that this is in line with what we see available out there.....a good steel frame weighs about 3.5 to 3.75lbs no matter how you put it together.

Let the flaming begin!

Dave