2018 Trek FX3
 

Wonder what's up with Trek moving the cables back outside the frame ? I thought internal cabling was an upgrade ?

Depends how one looks at it. To my mind, internal cabling is all well and good, provided the frame is constructed with internal guides that make cable replacement straightforward. Common now in carbon frames, not so much with metal.

Given a choice between internal cabling that requires 'fishing', and good ol' external guides, I'd choose the latter every time. Replacing external cables (inner/outer) is easy; internal w/o guides, not so much.

Oh I thoroughly agree ! I was pleasantly surprised when I found out after having to order a 2018 since there were no large frame 2017’s to be had !

Trek goes back and forth and has done that in recent years. You will even find some higher end model road bikes with external cables... like really?

I'm not a fan of internal cabling on my aluminum Norco either. It looks like it's been haphazardly done and quite a bit of housing rattle, at least in my mind.

I’ve heard about internal routed cables making noise. I glad to find out my new FX3 is external !

No. It's not an upgrade or downgrade. It's just a way to run the cables. I prefer internal myself for a cleaner looking bike.

Some of my bikes use external routing, and some use internal routing. Those with internal routing for some of the cabling include a 2006 Trek 7100, a 2015 Trek Verve, and a 2015 Raleigh Alysa. None of them have any cable rattle, and I do appreciate the cleaner look it offers.

There are some opportunities missed in some areas, though. My 2015 Trek, for example, routes both derailleur cables through the down tube, but they exit out just upstream of the bottom bracket into two cable stops, and then bare cables run across a conventional cable guide. The look is clean, and there's no paint wear on the head tube from cable housings as with conventional external cabling on the down tube, but the cables are still subject to debris kick-up from the front tire under the bottom bracket shell.

I wish Trek did this like they did it on the 2006 7100 that my wife rides -- the cable housings exit the down tube through a "slit" at the bottom and continue under the bottom bracket shell as individual housings. The front cable wraps under the bottom bracket shell and to a cable stop that points up at the derailleur. The rear cable continues past the bottom bracket shell and into a cable stop at the front of the right side chain stay, just aft of the kickstand mounting pad. I prefer that because the cables stay in their housings and don't get any kick-up from the front tire.

I guess the cable routing I prefer above all else is the top tube method. That is, the rear brake cable and both derailleur cables run along the top of the top tube, exposed (or not). The rear brake cable veers off to the left side of the seat post, the rear derailleur cable veers to the right of the seat post and travels down the right side seat stay, and the front derailleur cable veers to the right of the seat post and curves down to a top-pull front derailleur. I think that keeps the down tube area looking clean and keeps the cables as clean as possible, without the potential for internal cable rattle and without the need for any special tools or techniques to replace internal housing.

The '14-'17 FX bikes with internal routing have guides in the frame and don't rattle. Zero problems with mine after 3 years.

On some bikes there is a rattle, on some there isn't. I have internally routed cables on my 2015 trek fx 7.4 and that bike is absolutely silent when i ride it. and as others have mentioned it makes the bike look super clean.

admittedly, I don't ride often but each time i take the bike out, i am always surprised at how silently the bike performs.