Cable Routing and Other Frustrations
If you’ve been around mountain biking for as long as we have, you’ve seen many, many changes. Both bikes and components have been transformed by advancements in design and technology. Most of the time, it feels like progression. Sometimes it doesn’t.
We build a lot of bikes and we look at a lot of bike porn on the web. It’s cool to see how different bike builders tackle the same simple problem – how to get the cables and hoses to the right parts of the bike in the best way. It may be hard to profess ourselves as experts in this arena as we’ve never attended a clinic or been to the university for a semester of study in Hose Routing 101. However, we have an ex-bike company founder/owner and a couple of amateur framebuilders on hand, so we know what we think sucks, and from time to time we’ll see or work on a bike with cable and hose routing that leaves us scratching our heads and wondering what happened. Sometimes it seems that designers concentrate on swoopy tube shapes and linkage points and then take an extended lunch break while the janitor comes in and configures the location of the cable stops.
We reflect often on our periodic frustration and have come to the realization that normally, what bothers us about annoying cable and hose routing is usually only aesthetic and doesn’t affect the performance of the bike in the least. Usually. Other times we can’t help but think that it could be done a different way and improve performance. Mountain bikes have become a complex thing, and a plethora of rear suspension designs leave bike designers with options for routing -- down tube or top tube, top or bottom of the tubes, even the side. What to do?
That’s a good question. Component manufacturers are all over the board with no real standard for cable or hose entry to derailleurs and brake calipers. For example, top-routed XTR front derailleurs require a cable entry ranging from 20mm left of seat tube center to 55mm right of center depending on bottom or top swing model configuration. What’s a bike builder to do? If you optimize the placement of the cable stop for one, it won’t work well with the other. Then you commit to a derailleur model and hope that Shimano continues to produce it for the foreseeable life of the current bike design. The only problem is that perhaps your customers want to run SRAM gear. Most likely, a top pull option will leave the cable entry point on the other side of the seat tube than a Shimano, as is the case with the low clamp derailleur.
Bike designers must know this, so they try to solve the issue with a middle-of-the-road cable stop location. Remember what Mr. Miyagi said about being in the middle of the road?
Brake calipers are no better. Some have a hose entry on the outside, some on the inside. Some have banjo fittings which allow us to rotate the angle of the hose to accommodate the specific geometry of each bike. Why have a superfluous loop of hose flopping out in space when it can be tucked in nicely along a fork leg or rear stay? Banjo fittings. Anyone hear us out there?
We’d love to see some changes get made. Here are some examples of things to remember -- bike builders take note.
- Curvy bike tubes can be really sexy. We like full length housing on these kinds of bikes. We assume lots of work went into the design and manufacture of the sleek tubing. Why muck it up with split cable housing and straight lines?
- Cross as few tubes as possible. If a brake caliper mounts on a seatstay, then run the hose up the seatstay. Of course, this probably necessitates a top tube routing. No matter what side, inboard or out that the hose enters the caliper, it will lay nicely along the top of that stay.
- Don’t split the derailleur housing just for the sake of splitting it. If the gaps are so short that you can’t slide the housing enough to clean and lube the inner wire effectively, then what’s the freaking point? Run full housing and be done with it, or go back to the drawing board.
- Incorporate hose guides and cable stops into structural components, ex. shock mounts. Remember -- kill two birds with one stone.
- Twisting a hose or cable around a tube looks like shit. Our eyes like parallel lines. If you must ‘clock’ a hose or cable around a tube, run it as straight as you can for as long as possible before making a transition.
- Don’t be stingy with hose guides. A down tube or man-sized top tube needs three hose guides. Two will not do. For that matter, maybe two guides on a rear stay for a brake hose should be the standard.
- SRAM rear derailleurs look awesome with the cable routed down the seatstay. It also works best for Shimano Shadow units and eases the angle of the loop required for normal Shimano derailleurs as well. Why ever put the cable on the chain stay?
- Nothing will shred a pair of jeans faster than a poorly placed and unused rear derailleur cable stop on a single speed dirt jump bike. We like the way standard hose guides are super low profile when not in use. Maybe the best way is to forgo split housing for bikes intended for single/multi speed use.
- There is no worse routing than taking the rear derailleur cable along the long axis of the shock. What’s going to happen to the cable when you cycle through the travel? Hint: if you’re lucky it will only rub a hole through the frame -- worse yet, it might also flop to the outside and rub a hole on the inside of your knee as well.
We’re sure that there may be more cable and hose routing offenses that we can’t think of at the moment. Perhaps later we’ll add to this list. Through this exercise, we’ve remembered a couple other design flaws that we’d like to see go away:
- Why thread main pivot hardware in from the drive side of the bike? With the majority of suspension designs having a pivot near the bottom bracket shell, it is safe to assume they’ll all be obscured by the crank and/or chainrings. Why not make sure that pivot maintenance can be done easily from the accessible left side of the bike? This seems like a no-brainer to us.
- Though we understand that differences exist between shock manufacturers and where they place the damping controls and air valves, we’ve always wondered how a bike gets through design and production without easy access to all these features. We want access to our ProPedal lever and the air valve -- with no wrenches!