Our newest S and S Coupling with internal lugs (the ends fit inside the frame tubes)
For the couplings listed below, the area that forms the internal lug needs to
be machined to fit the inside of
For production runs, we manufacture the lug diameter to fit the tube being used.
These photos of a Surly Trucker Deluxe, built with our new BTC2 Couplings, were provided by Surly
Frame Tube Diameter Tube Wall thickness Coupling Weight*
1 1/8" 28.6 mm .020" to .040" 4.51 oz. 128 grams 1 1/4" 31.7 mm .020" to .040" 5.11 oz. 145 grams 1 3/8" 34.9 mm .020" to .040" 5.57 oz. 158 gramsThe BTC2 Couplings listed here are our "zero" wall type meaning that they are designed to work with tubes with a wall thickness of .020" minimum to .040 maximum. The lug portion of the coupling must be machined (turned down) by the framebuilder to suit the inside diameter of the tube being used. BTC2 Couplings are suitable for new frames or retrofits. We can also do production runs to fit specific tubes however we don't stock them.
Mechanical Properties of Materials