Internal Cable Routing and Sluggish Shifting
A version
of this article was originally
published in Triathlete Magazine
I absolutely love the ride of my Guru Crono. My only question is that the shifting does not seem to be as “snappy” as my old road bike. I recently had the derailleurs adjusted and replaced the cables, but it didn’t seem to change it. What else could be going on and do you have any other suggestions?
Tim, via E-mail
Dear Tim,
Your Crono is a really nice riding bike. Like most aero frames, in an effort to maximize aerodynamics and shield the cable from the elements, Guru routes the derailleur cables inside the frame. Internally routing cables through tight areas, like the bottom bracket, can make the shifting feel less crisp as the cable simply has to overcome more friction from the additional turns and tight areas that it routes through. There are a wide range of internally routed frame designs on the market ranging from simple down tube only systems to completely enclosed systems that shield the cable from the shifter all they way to the derailleur. Almost all internal systems are more difficult to keep well lubricated than external systems and some designs have lower friction than others. Your frame size and geometry can play a role in this as well.
While it is unlikely that you will be able to get your internally routed cables to feel as crisp as an externally mounted road bike, internal cable routing should not create unreasonable cable friction. For best results, make sure that the cable is shielded with a plastic cable liner wherever it comes in contact with the frame, that the cables are routed with as few kinks or bends in the housing as possible, and that you lubricate the cables frequently. Some frames can benefit from one of the low friction cable systems like those from Nokon and PowerCordz. Nokon’s aluminum housing/Teflon lined system can help get around tight corners smoothly and requires less frequent lubrication than standard cables, making them helpful for small frames or anything with tight cable routing (www.nokonusa.com). PowerCordz synthetic cables can be used with traditional housing and are low friction, corrosion proof, require less frequent lubrication, and are under half the weight of a standard metal cable (www.powercordz.com).
The Nokon and PowerCordz systems are more expensive than standard cables and housing and installation can be a fair amount more complicated too. Performance with either system will only be maximized if they are installed properly, and improper installation can actually lead to poorer performance than standard cables. The assistance of a skilled technician – not just “the kid at the local bike shop” or your brother who helped you unclog the sink last week – is highly recommended.
Enjoy the ride and train hard and smart!
Ian
Originally published January 2007/Copyright © 2007
