Yikes is right !!!!!!!! That is a titanium coupler correct? Any large impacts that you know of? At least it's a warrantty repair if that's any consolation. Any idea what the discoloration is?
Are they stainless and rusted on the inside?
Please let us know what it is like when you replace the stainless nut.
That rubber mallet thing is troubling; ref. the User's Guide:
When you screw the coupling together or take it apart, be sure to align the frame in a manner that allows the nut to turn easily by hand. Turning the nut with the wrench should only be necessary for about the last 1/4 turn when tightening and the first 1/4 turn when loosening. Careful alignment will minimize thread wear.
Inspect the couplings frequently for wear or damage.
Tighten the nut with the spanner wrench to at least 35 foot pounds of torque. That requires at least 70 pounds force against the end of a 6" wrench. I typically tighten the nut as tight as I can get it (I don't think it's possible to over tighten the nut with our 6" wrench). Remember, the 35 foot pounds of torque is a minimum value and your cycle may require a higher torque value to keep the nuts tight.
Be sure to apply the force at 90 degrees to the wrench.
A doubled over cycling glove laid over the wrench will allow more pressure to be applied to the wrench. Without the glove, the narrow wrench may hurt your hand.
Since a maximum torque value isn't provided, that may be the "out" vice the description provided.
Anyway, complete and honest disclosure from me to S&S and they are not looking for an out, they are being totally nice and sending me a replacement and didn't even take offered credit card details for shipping. They are also very interested in taking a look at the failed nut, which I will send back to them in short order and if anything interesting comes out of that I'll update this thread. Sounds like maybe they wanted to confirm that nut was heat treated, which maybe you can detect visually via orange coloration on the inside of the nut.
Last edited by mburchard; 07-18-13 at 12:52 PM.
Keep us posted; something interesting always comes from these discoveries.