An ounce of prevention is worth a pound of cure. A stitch in time saves nine. Procrastination is the thief of time. Shifter maintenance. Most shifter problems can be prevented long before they become issues. The best thing you can do to preserve your shifters is to replace the cables often and keep your shifters clean and lubricated.
Eventually all cables will fail after a certain number of shifts. This number will be influenced by the shifting force applied by the rider, the design of the shifter, and how much the cable is required to bend inside the shifter. For example: the last generation of Shimano road shifters (where the shifter cable was not run beneath the bar tape) bent the cable close to the head and after time metal fatigue can fray and eventually snap the cable. Pieces of wire can then lodge in the mechanism or the disembodied cable head can get jammed in shifter, effectively destroying it.
It is a good idea to change shifter cables as often as you change chains or at the very least at every other chain replacement. Of course cables should also be replaced when increased effort is required at the shift lever or when shifting becomes sluggish. When I replace a shift cable, irrespective of brand or intended use, I like to give a sprits of Boeshield T-9 aerosol lubricant into the guts of the shifter. This will flush out dirt and loosen up any older lubricants that have started to solidify due to contamination or age. I can’t emphasize how important this is to keeping your shifter working smoothly and precisely. No need to over do it though, just a little half-second spray in two places will do the trick.
I’ve seen many old Shimano road shifters die unnecessarily as a result of failure to do this very simple preventative maintenance. Without proper lubrication the small shifter lever cannot move independently of the larger shifter/brake lever, which makes cable release difficult or impossible. If you have a shifter that is frozen, there are ways to bring it back to life without disassembling it but I will save that discussion for another post. As far as serviceability is concerned amongst road shifters here is the breakdown (pun fully intended):
Sram shifters are rebuildable but I do not recommend doing this unless you are very confident in your abilities and/or apprenticed as a watchmaker or jeweler. If you do rebuild them, I recommend replacing the entire mechanism at one time rather than attempting to replace individual small parts. This is generally how all SRAM products (brakes, forks, etc.) seem to be designed. Internal parts are best replaced as modules or subassemblies. Shimano shifters are officially not rebuildable. However, it can be done but it is extremely difficult and no replacement parts are available. In order to do it you will need donor parts and the skills of a professional watchmaker or jeweler. If you do want to attempt it, instructions can be found here.
Campy shifters are fully rebuildable down to the smallest parts. Many parts are interchangeable from generation to generation making it possible to change a 9 speed shifter to a 10 speed. Campy shifter rebuilds are not all that difficult to do either. All of the replacement parts are available, but they don’t come cheap. Another thing to keep in mind is that Campy shifters need to be overhauled on a regular basis (anywhere from 1-4 times per year depending on use) to keep them working in top condition. For official videos on how to do it, take a look here.
Daniel Slusser is a professional bicycle mechanic with over ten years of experience. He holds a bachelor’s degree in business administration from HSU and a master’s degree in history from Cal Poly University. When he is not riding, wrenching, or writing he enjoys spending time with his wife and two children.