S and S Machine
Bicycle Torque Couplings (BTCs)
Your Travel Bike........Your Only Bike!

Stainless Steel BTC2™ Specifications


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 the tube.
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

Coupling Size and Weight (only 3 sizes being offered)

 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 grams
The 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.

*Important: to calculate the weight increase resulting from adding couplings to a frame, subtract the weight of the piece of tube removed for each coupling added. The length of tube that is replaced by the coupling is about 1.750" long.


Mechanical Properties of Materials

                            Heat    Hard.  UTS    .2% YS   Elong
Part Name       Material    treat   Rc     ksi    ksi      % in 2"

Coupling Lugs  17-4 PH SS   H1150   c33    145    125      19
Coupling Nut    17-4 PH SS   H900    c44    200    185      14

Data shown above is believed to be representative but should not be used for design or application selection purposes. Specifications are subject to change without notice.

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S and S Machine, 9334 Viking Place, Roseville, CA. 95747
TEL. 916-771-0235 FAX 771-0397
e-mail: sns.info@sandsmachine.com