fogrider

to answer the question, lugs allow lower heat. this is important in when steel would become very weak with the higher temps of welding. the lugs also reinforce the area of the connection. many tig welded tubes are double butted tubes to bring the weight down. I don't want to get into what is better...

Nessism

Have to agree with Botto on this one, lugs are about the "look".

Brazing is performed at lower temperature than welding (TIG) but modern tubes don't care either way so this is not relevant unless you are using an old tubeset like 753.

Lugged frame repair is more difficult than TIG repair because of the nature of the lugged socket - more of the frame must be pulled apart before the new tube can fit in.

Lugs can be bent so as to accommodate a fairly wide range of angles. It's more work to do this type of adjustment thus lugged frames are more labor intensive, thus the higher price.

botto 

wrong thread.

schnee

It didn't used to be that way. Early on, the steel used lost a lot of tensile strength when heated, and since brazing requires far lower temperatures than welding, the tubes and butting could be a lot thinner on lugged frames. Steel has come a long way since then though, so the differences aren't nearly as pronounced.

bbattle

Links to lovely lugness:

https://bikeforums.net/showthread.php...highlight=lugs

https://bikeforums.net/showthread.php?t=358074

https://bikeforums.net/showthread.php...highlight=lugs


Freakin' Sweet Hetchins Lugs
https://www.hetchins.org/504xc1.htm

bbattle

carbon tubing with titanium lugs

Mooo

Umm, 4130 is still 4130. And has been since at least the 20's or 30's. You can get it lugged or welded today. For that matter, weren't the penny farthings welded?

Reynolds 531, OTOH, I understand did not lend itself well to welding.

But... Pretty sure the answer is economics. If you can source 3 welded frame sizes to fit the biggest chunk of the market, and get some differentiation by using a slightly different size tube, why go lugged? Large diameter tubes are what people expect from a road bike. Sloping top tubes too. Part of the side benefit is disposable components. If there is no standard size of anything to bolt to, derailleurs, shifters, and other components can be changed more easily year to year forcing the old stuff to be dumped. Solves lots of problems.

I'll betcha low spoke count wheels have an origin in economics too ("if we can save $0.75 cost in spokes on say 200,000 wheels a year and the quality doesn't totally tank, isn't that good enough?").

schnee

You're absolutely correct, but completely missing my point. The original statement was about weight. All I'm saying is that lugged bikes are not necessarily heavier due to other factors. Here's a link that explains it better than I did.

Nessism

The lightest steel frames are TIG'ed since they use killer thin, super large diameter tubes for which lugs are not available - S3 and EOM16.5 for example.

If we are talking about apples to apples such as to compare regular OS tubed frames both with lugs and without, the lugged frame will be slightly heavier. There is just no getting away from the fact that the lugs have metal in them. One good offset in favor of lugs is that the head tube can be thinner and there is no need for a collar or butted seat tube with extra thickness at the top (which is typically used for TIG frames).

Don't get me wrong, I like lugs and my frames have them. I couldn't care less if the frame is 100 grams heavier, since I like they way they look.

ridethecliche

The peugeot ph501 I just sold had a 59 cm top tube and it was still lighter than the trek 760 I just bought that's a size 56cm top tube.
The lugs are sweet though

kill.cactus

HAHAHA

I thought the title of the thread was "what's so great about lungs"

Mooo

You are absolutely correct; I completely missed your point. Oh well