So I've recently upgraded the groupset on my cannondale caad8 to the 11spd 105 5800 group.
Everything is working great but I've ended up without a barrel adjuster for my front mech as the gear cables are now routed under the bar tape where as the external routing on my old setup had the adjuster at the shifter end of the cable.
Its a bit annoying as I now have to readjust the front mech by undoing the pinch bolt to re-tension the cable and cant really fine tune it.

I'm looking for advice around adding a new barrel adjuster to this setup.
The downtube boss for the cable is non threaded and the cable ferrule is held in by the cable tension.

I've had a look online and seen people talking about threading this boss to install a threaded adjuster and other solutions that require splitting of the cable outers to install an inline adjuster as part of the cable outer.
Id prefer something simple that I can simply install into the current cable boss but I'm not really sure what my options are.

Anyone else been in this situation before and have some advice?

Check out "RJ the bike guy" on YouTube. Seems to me he recently did a video on just that problem.

If it has a shift lever boss the piece you put over it has been made to do that.

If it doesn't an inline cable adjuster can go in the housing Run ..

Can't you get a barrel to add where the frame boss captures the housing?

Shouldn't you have one for each side (front and rear adjusters) that adjust tension on the cable housing? Would have been included with the shifter cables.

You can do inline but I don't understand why you should have to.

Do a web search for downtube cable adjuster, you'll find more information than you bargained for. They're common and standard on new bikes that have under the tape cabling.

Yeah, I kinda wanted to avoid the inline thing. I'd prefer to get one that slots into the frame as it seems like a cleaner approach.
Only thing is that I'm unsure whats compatible, a lot of the parts that ive seen have people commenting in the reviews saying that it wont fit the cable stop bit so I'm not sure what will work in my situation.

I was calling this cable stop bit of the frame a boss but maybe I've confused my terminology here :-)
I'm attaching an image to give you an idea of what I'm talking about.