Derailleur Hanger Alignment

In the early days of index shifting when the first systems were 6,7, and 8 speeds, derailleur hanger alignment was important, but not crucial to shifting. Due to the wider spacing between cogs, the derailleur hanger could be bent slightly, and the derailleur might still shift reasonably well. However, with the new 9 speed mountain bike cassettes (10 and now 11 speed for road), proper derailleur hanger alignment is absolutely imperative. Even a slight deviation of the hanger can cause incorrect shifting, and also cause the derailleur to shift into the spokes of the wheel, or jam the chain between the cassette and frame.

Whenever I build a new bicycle, I always check the derailleur hanger for alignment. Without fail, they are slightly bent (or worse) every single time. This cannot be avoided due to the initial fabrication of most frames, transportation, etc. A common mistake made by riders is to think, “I just bought a new hanger, so I will bolt it on and it will be straight.” The logic seems correct, but this does not take into account the fact that surface of the frame where the new hanger attaches is not necessarily aligned (usually it isn’t).

The replaceable derailleur hanger is a relatively new item, but it has saved many frames from the junkyard. In a crash, if the derailleur is near the smallest cogs, the derailleur will become bent severely – causing the hanger to become bent in the process. The replaceable hanger is designed to bend easily or break off in the event of a crash. Steel frames without a replaceable hanger can usually be bent back, unless the threaded hole has become elongated from an extreme bend. Aluminum will fatigue and fail after only a few cycles of bending. In the event that a non-replaceable derailleur hanger on an aluminum frame is bent, extreme care is required when it is aligned. There is a high likelihood that it will snap. Regardless, the hanger will be weakened, and will be more likely to bend in the future.

To achieve proper hanger alignment, a derailleur hanger alignment gauge is used. Using the rear wheel of the bicycle as a reference, the gauge is used to bend the hanger so that the hanger is in the same plane as the wheel. This is not rocket science, but it does take practice to prevent breaking the hanger. Due to the cost of the tool, it is probably best to have the alignment checked by a qualified shop when there is an issue with shifting, or after a crash.

Solving Bicycle Noise Issues

Bicycle noises can be one of the most aggravating problems for cyclists. Although most do not cause any damage to the bicycle, they can make a ride completely miserable. I have seen cracked frames on rare occasions, but the culprit of a noise is normally something simple. There is not one root cause for squeaks or creaks, but they can usually (key word) be found quickly if investigated in a thorough and logical manner. I will not mention torque specifications since the average rider most likely does not own one, and these numbers can vary.

Whenever two metals come in contact with each other (especially dissimilar metals), there is a chance for a noise issue to occur. Application of grease not only allows the threads, spline, etc., to become tighter, but it also acts as a noise insulator in case there is any gap between the metals. Lithium bicycle grease is the most popular.

When trying to eliminate a squeak or a noise, perform one adjustment at a time, then test ride the bicycle. Although the disappearance of the noise is the end goal, nothing is gained by eliminating it without discovering the root cause. Do not wash the bicycle before the problem has been solved - water acts as a lubricant, and will cause the noise to disappear until the water evaporates.

The most common noise is a clicking while pedaling the bike. This is a drivetrain issue. The first thing to investigate is whether the pedal threads have been greased and/or that the pedals are tight. Although greasing threads seems counterintuitive, adding grease to (most) threads on a bicycle can eliminate almost all creaking Remove the pedals, lubricate the threads, and reinstall. Make sure that the pedal is tight, but do not over tighten.

When a creaking noise originates from the crank, it is most likely the left pedal or crank. Why would this be, since we apply the same pressure to both the left and right pedals? The left pedal receives the torque in a binary (on/off) manner — when the crank is pressed down at the top of the stroke. This is then transferred to the bottom bracket in the same position, time after time. The right pedal (drive side) receives torque in a much more distributed manner, since it is being divided over four or five arms on the spider from the chainrings. Of course, with the introduction of two-piece cranks, the loosening of the crank at the bottom bracket spindle is no longer a factor. However, 99% of the time, the left pedal is still the pedal which is creaking.

The next thing to check are the chainring bolts. If I am checking them, I normally remove them and apply grease to threads before tightening. Again, use uniform torque without stripping the threads.

Working backwards from the bike, check anything that the drivetrain might affect — grease the dropout and frame interface as well as the bolts/screws, check the tightness of the quick release skewer (even grease the face of the frame where the skewer attaches), etc.

Creaking seats can be a major problem as well.Often the noise is associated with the drivetrain, but it is actually caused by the rider changing position on the saddle, causing the rails and/or clamp to creak. Try wrenching the saddle back and forth to see if the seat is the problem. If so, remove the bolts and grease the threads, grease the rails, etc. Sometimes the point of attachment at the nose or in the back — spray a teflon lubricant in these areas if greasing the clamp/bolts did not eliminate the problem.

Due to the in-depth nature of suspenion problems, I will discuss this at length in a future article.