In my search for a new bike, I've run across a couple that have the cables (or at least one anyway) routed through the top tube. It was rather nice to pick up a bike and not have my palm or fingers encounter cables...

Some frames are a PITA to run cables through- some are only annoying until you figure out the trick. I like my frames with traditional exterior routing just for simplicity's sake.

The problem is if you break a cable and have to re-thread it. Happened to me once in 7 years of having an internal cable in the top tube.

If the old cable is intact, you just slide some liner over it before you pull it out, then slide the new cable through the lining - then pull the lining back out.

There are different ways of creating the internal routing on the frame though, and some are better than others when it comes to cable drag.

True. The better independent framebuilders use tubing inside the main frame tube to guide the cable. No threading issues, negligible drag. As for the mass-market frames, it's anybody's guess. I'd be very surprised though if they made it a PITA to change the cable.

You could always ask the mechanics at the LBS where you saw it how easy it is to rethread the cables on that bike if one were to break. Out of curiosity, I did some checking. Some frames make it real easy, with others it's trickier but not ridiculously so. There's an old thread in the mechanics forum with a bunch of tips.

One interesting one for a difficult frame involved taping over all the holes in the frame except for the entry/exit holes for the cable you wish to thread. Run some string into the entry hole and use a vacuum at the exit to suck the string out. Another option was sort of the reverse, - use an air compressor with the regulator set at about 10 psi to blow into the entry hole. The string will magically appear at the exit hole.

Other people used things like spokes to fish a string through. Another guy said that many frames that appeared to be very difficult to thread cables through suddenly got very easy once you removed the seat post.

I'd personally like internal cable routing but I'm fine with external too.

Well, at the price point I'm currently shopping at, the routing varies. The Specialized Sirrus appears to have the rear brake cable routed internally, and I know from looking at them yesterday that two cables run along the exterior of the downtube. GT Traffic looks like the rear brake cable is exposed, and at least one of the shift cables is routed through the down tube.

In the past ive used products like this https://www.harborfreight.com/3-16-in...rce=googlebase
I for years rode a specialized Fatboy bmx that had the simple holes cut in tube and i just fished it through with one of those it wasn't too big a deal, im mean sure its more of a pain than external wires but not impossible.

A friend has a 20 yr old Italian racing frame w/ internal cable routing, it is gorgeous

my tommasini has an internal rear brake cable but has a small tube that guides the cable all the way back.

You can always fish a cable through a hole with a small gauge wire bent into a U at end (in the case where there's no carrier or through-housing). It's a simple job.

Another trick is to start with sewing thread and use a vacuum cleaner to suck it through

Dunno, but if it's anything like my BMC it's a PITA to route a cable. ALL it's cables are routed internally.

My BMC's brake cable was really easy to route. I assume they have a tube for it. The downtube cables were a pain in the ass, though, like you say. I should have soldered or glued the ends before trying to fish them through because one of them started fraying.

I think the real question is whether you're going to do your own work on the bike, or if you'll bring it to a bike shop when it needs some TLC?

In my short time of actually collecting bikes (and selling half of them off ), I've learned that they're a lot easier to maintain than people think. The PITA internal cables on my BMC were still easier and quicker to finish than a battery relocation kit on my car, for example.

IMNSHO, a bike commuter should be able to nearly tear down & rebuild a bike to its bare frame and back. I'd be satisfied with knowing all the work that can be done with screwdrivers and some Allen wrenches (which is most of what can be done on a modern bike anyway).

As far as internal vs external cable routing goes, one option would be to choose a frame with its cable(s) routed on top of the top tube. My commuter's rear brake cable is like that, so lifting it up isn't hard on the cable at all.

Yeah, mine's a TT frame so they made it doubly hard!

Personally? Initially, the LBS will be doing most of the work- I will take up the slack as tools and knowledge is accumulated.

The main point of the question, I guess, was is there a real benefit of having the cables routed internally? And if there is a real benefit, then why aren't there more frames that route them internally?

magnets are good for fishing. if you are replacing existing cables, slide some small diameter tubing over the old cable to use as a guide.

I suppose there's some minimal aerodynamic benefit. There's a benefit in having the cables less exposed to the elements and less likely to get snagged on something. A lot of it I think is just aesthetics.

For me internal vs. external is very unlikely to be a deciding factor between two bikes but all else being equal I like the cleaner look of internal cable routing.

I've got two bikes currently with internal routed cables and I've previously owned others. Internal routing is nice because it looks cleaner and the cables don't get in the way if you ever use a car-mounted bike rack to carry your bike. Also, external cable mounts tend to get paint chips that eventually allow rust to form. Many older frames with external mounts have rust around the mounts, if you ever shop for older bikes.

If your bike is maintained by a LBS, internal routing seems like a no-brainer, all things being equal. Most Italian or European steel frames seem to have come standard with internal routing over the past decade or so. However, if you are buying a new custom frame, internal routing will definitely add to the cost. I probably wouldn't be willing to pay for internal routing if buying a new custom frame because they are so expensive anyway, but I would look for that feature if buying a used or NOS steel frame.

+1

Beyond what you mention, it's a lot easier to clean and wax the frame without the cables getting in the way. It's not something I do often but it's part of my routine to prepare the winter bike for use. Things like frame bags are easier to get on and off if you don't have to feed any straps under cables.

I think being able to do away with these minor inconveniences probably makes up for the challenges of running new cables, -which would only be done once every few years at most.