Old reliable no more

Shifting problems barely existed before the invention of indexed shifting. Now they're a regular annoyance for riders in all categories.

In my private war to eliminate 4-millimeter shift housing, inline cable adjusters have been a reliable ally. But the bike industry has finally figured out how to mess that up.

For years, 4mm housing used thick-walled ferrules that made the ends fit into the 5mm cable stops commonly in use. Because of this, it was easy to substitute 5mm housing to reduce friction in a system that was getting erratic.

Because mechanical indexed shifting relies on perfect cable tension, shifting systems included fine tuners in the form of barrel adjusters somewhere in the cable run for all rear -- and most front -- derailleurs. Lately, barrel adjusters have become a necessity for front shifting because the indexing requires higher tension than you can get just by pulling on the cable as hard as you can when you hook it up.

At the same time as shifting systems have evolved a need for super high tension, the trend to run all the cables inside the frame has led to systems that can only use 4mm housing, because the cable stops are holes built into the frame and do not accommodate -- or need -- a ferrule. However, with inline adjusters I could reduce the 4mm section to the bare minimum needed to enter the frame, and put 5mm from the shifter to the adjuster. With ferrules on the housing, 4mm could go in one end, and 5mm in the other. So the bike industry introduced 4mm adjusters that take naked housing with no ferrule. But they still made the 5mm adjusters as they did before. I could sub in a whole new adjuster.

Not anymore. The last 5mm adjusters I ordered in blissful confidence were sized for 5mm housing without ferrules.

Linear-wire shift housing has always needed a strong ferrule on each end to keep the stiff wires from poking through under the pressure of the shift cable tightening. We used to see ferrule failure a lot in the cheesy plastic ferrules on 4mm housing. The extruding wires would burrow into the shifter, making shifting maddeningly inconsistent, and sometimes even damaging the mechanism. That has gradually faded away as we see more metal 4mm ferrules and perhaps some reformulated plastic that is less prone to punch through. But that does not do away with the problem of drag from the skinny housing. The skinny housing is often applied over thicker cables with coatings that are supposed to make them slide better, but usually end up turning into lint in there.

The answer has always been 5mm housing and a 1.1mm stainless slick shift wire with no coatings of any kind. That's it. No secret formulas, no chemical agents, just the largest available housing with the skinniest available cable. And now you can't have it. As cassettes get more crowded and spacing between cogs gets smaller, smaller deviations make a noticeable difference. The bike industry once again makes riding less convenient and more expensive.

Internal cable routing is better

Bike frames are built to withstand pedaling forces, cornering forces, and road shock. These all impact the structure in sort of broad, general ways. Cable forces put point loads on very small areas of the frame. They're not huge forces, but the strength required to hold up to them is quite different from the more distributed stress of being a bicycle. 

Internal cable routing may seem like a needlessly complicated answer to a relatively trivial problem of air drag -- because it is -- but it also strikes me as a better way to load the carbon fiber frame, compared to attaching external cable stops. Because I don't build my life around the latest technology, I may have missed a memo on this. I focus on the annoyance of working on things that I can't see and can't reach. Belatedly I realized that it's probably easier and stronger to make reinforced entry and exit holes than it is so attach external anchor points.

A few years ago, Specialized road bikes even came with instructions not to pull on the external cables to seat the housings as we would with metal frames with welded cable stops. The stops on these carbon frames could pop off if pulled outward. External stops on all carbon bikes displayed various ways to reinforce the bond, including little pop rivets.

It's still a pain in the ass. If it went away I would not miss it.

On metal frames, holes may be a liability. Back in the 1990s I found cracks in an aluminum Klein frame at the entry hole for an internally routed brake cable. Aluminum being aluminum, this represented a potentially terminal condition. There seemed to be no good way to stop the crack from spreading in the thin metal, at least not with the skills and equipment available in our shop. The owner seemed angry at us for finding it. But to know is to be responsible. We couldn't just let him ride on it without knowing his risk.

Not every shop agrees. A customer brought in a Dahon folding bike to get a flat tire fixed. He complained that he had taken the bike to a shop where he lives, to get tuned up and have the tubes replaced. The shop did the tuneup, but didn't do the tires. As he went on at some length, he mentioned that the other shop had told him there was a hairline crack in the head tube. Without explaining the dangers of abrupt catastrophic failure in aluminum, they took his money for the tuneup and told him to "keep an eye on it."

The bike had been fitted with a very tall stem riser, atop a very short head tube.

Leverage is an amazing thing. The "hairline" crack was not hard to find.

We refused to work on his bike and advised him to junk it. Considering that we left him with the flat tire, he wasn't likely to jump on it soon.

Next up was a brake bleed on a mountain bike. There are two kinds of bleed: the classic removal of air from the line, and the more medieval leeching of excess fluid when someone filled the system without resetting the pistons first, leading to hot-weather lockups. This bike only needed the latter, which was nice. But some idiot somewhere had cut the rear brake line so short that I don't know why the rider hasn't torn it loose just making a tight turn, or in a mild crash that yanks the bars around.

I could go on, but the morning is evaporating quickly, and a long queue of repairs is still piled up at work.