2016 Trek Domane SL 4.5, Ultegra components, carbon frame.
Riding yesterday and this part broke 5 miles into a 50 mile ride (zip ties to the rescue!). Not sure the name, but it's on the bottom bracket holding the rear derailleur cable. I'd call it a rear derailleur cable stop, but what do I know. As you can see, it's where the sheath end cap is secured. Looks like aluminum that just snapped. 2 problems:
1. I don't know what this part is called, so can't really search for it. No luck on the trek site.
2. I can't tell how it's fastened. LBS told me 2.5mm allen key, but doesn't look like it to me. Looks like it's riveted?

Any help appreciated!

Aluminum Alloy Bike Frame Small Parts Double Single Cable Stopper Cable Hamger Carbon Bicycle Accessories Brake Shift Cable Seat - AliExpress
try googling riveted bicycle cable stop.

tried to copy the link but didn't work. In any case the source isn't encouraging but they're out there.
I'm interested as I have a titanium frame that uses them ( with tiny screws) and would like some spares.

Yes it’s a cable stop - maybe add « rear derailleur cable stop » or « drive-side chainstay cable stop » for more search specificity. It certainly looks to be riveted in place. If this were a metal frame I’d simply drill out the old rivet and install a replacement fitting with another rivet. However, I don’t know what the appropriate approach would be with carbon. Probably the same. A bike shop should be able to do this easily - if you want to do it yourself, you’ll need a drill or dremel, the appropriate stop fitting (doesn’t have to be identical or Trek-specific - it’s just a basic cable stop with a rivet hole), a rivet and the tool to install it. You can also get clamp-on stops, just put some wrap or tape under it so it doesn’t gouge into the carbon

That cable looks might dry-

Yes, that certainly looks like the part

My normal LBS didn't know (nor did a couple of mechanics that were set up during the ride), but I guess the chief mechanic wasn't in, said maybe come back on Monday. I've never seen a blind rivet that small, and didn't know if riveting to a carbon frame was common practice. Interested in the clamp on stop. Drilling out the old and replacing with something like that should be pretty easy. I didn't want to try drill out a threaded screw without realizing it and bugger up the threads.

https://www.aliexpress.com/item/1005010274712754.html or similar. It is fastened with pop rivets.

As it should be?

No. That looks like damage from something like road salt or unrinsed caustic cleaning products.

So after looking around some more:
1. That Ali express part seems to be the only one available. A few sources but same likely generic part.
2. Clamp on stops aren't plentiful. One basic hinged aluminum design (origen8 brand and knock offs) but for a round frame and wrong size
3. Definitely looks riveted, and I don't see another good way to fasten it. Putting a rivet into the carbon doesn't excite me.
4. Many examples of people doing various conversions that don't use the stop and just fasten a longer length of the sheath to the bb. Using zip ties
4a. A worm clamp around the end cap would probably work great but look lousy and might dig into the frame over time. Trying to think of something else along those lines, preferably plastic

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