Why are lugged frames better

You may have heard of a lugged frame. Lugged frames were once considered a work of art. Cyclists waited months or longer for a custom, lugged frame from a master builder. Contemporary lugged frames are found primarily on quality, hand made bicycles that remain true to the art, design and strength of hand-crafted bike frames.

A lug is a jacket, sleeve or fitting that joins two tubes together — think of PVC pipe fittings. Lugs can be found on almost any type of frame material including carbon. Lugs can be almost any shape, as long as they do the job of joining tubes together.

Custom bike builders often make their own, but lugs can also be purchased generically. Carbon lugs are glued on. Steel and other metal lugs are typically brazed on.

Lugs offer several advantages to a bike frame. They strengthen the joint by adding material to the stressed areas, and distributes the stress over a large area. Since steel lugs can be brazed on at lower temperatures than welding requires, frames have more integrity. Lugs also have distractions as well. They must fit perfectly. The diameter of the lug must match the diameter of the tube. Loose play is not acceptable, and purchasing generic lugs for generic tubes may not always work out.

Most modern frames don't have them. How come? They're more expensive to build with; and from a strictly practical point of view, they're unnecessary.

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. Why brazing rather than welding?

Less heat, mainly. 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. It comes down to this: Good lugged frames are 10x as nice to look at as welded frames are, and they're much easier to repair. Is a lug a lug? No more than a knife is a knife. Some are well-designed to eliminate stresses; others accentuate stresses.

Some are thick, some are thin. Some fit the tubes well, others don't.