Llewellyn – Custodian Lug Set

By Darrell McCulloch (Lewellyn Bikes)

The Llewellyn “Custodian” lug set is the culmination of my long-time desire to create a traditional road bike level top-tube OS lug set with functional details to meet today’s requirements at the workbench. I envisioned this set as the keeper of the craft, the guardian of tradition and knowledge, allowing frame builders to build traditional level top-tube OS frames with well-designed lugs that meet contemporary build requirements. Released in February 2009, these are the sixth Design and Form by Llewellyn, the forth lug set.

The lug set sits along side the Llewellyn OS Compact lug set, so a builder can design frames with a either a level or sloping top tube using OS tube sizes.



There are many OS lug sets on the market, and I was using many other brands of lugs before I designed the Custodian set. However there were issues in each of these lug sets that I wanted to avoid in my style of frame building. Therefore, the Llewellyn Custodian lug set has many important features and versatility the other designs can lack.

This lug set had to have all the desired features such as:

  • Accomodation for a stainless steel M6 cap head seat binder bolt (which is the strongest and readily available),
  • Key hole slot with a shape to avoid damaging carbon seat posts,
  • Cast M5 gear with spring counter bore bosses on the DT lug to keep the paint tidy,
  • Lots of seat tube skirt to allow the builder to trim to fit their desired seat stay attachment style.
  • Lots of stack height on the top head lug that can be trimmed to suit the required frame design.

For the stainless steel version of the seat lug there is a shelf in top of the lug that sits on top of the seat tube. This avoids the exposed braze line between seat lug and seat tube and also removes the need to make a small piece of stainless tube to sit on top of and inside the seat lug to avoid the otherwise exposed rusty top edge of the seat tube.


No detail in the design is left out.

These lugs are also similar in shape to the OS Compact set but with a few tweaks to sate my desire for a curvy but simple lug shoreline that can be left as they are, or modification and or elaboration if so desired by the builder.


These lugs made their debut to the world in a polished lug Llewellyn Custodian frame painted by Joe Cosgrove that won the Best Paint award at the 2010 North American Hand Built Show.