Tuesday, January 25, 2011

gear shifting problems

Gear Shifting Problems

Bent derailleur hanger – this is a common problem where transportation, a fall or a knock on your derailleur can cause your derailleur hanger to become bent. All of a sudden some of the gears will not be working properly. Best solution is to replace the hanger, they are designed as replaceable parts, bending it straight is a temporary solution and will not solve the shifting problems.

Worn chain and or cassette – mis-shifts under pedalling tension when pedalling hard or when the drivetrain is dirty are typical symptoms. Check the chain length and condition of the cassette teeth, if either of these are worn they can affect shifting. Ideally the two should be in sync from a wear point of view, so often replacing both is the best option if either is badly worn.

Dirty, rusty or old cables – this is also a common problem, symptoms are lazy shifts where the chain shifts slowly either up or down. It is noticeable when the shifter is hard to operate and when there is a noticeable delay in shifting after clicking the shifter. If in doubt replace the cables, more often than not it will make a difference and make your bike feel much better.

Low cable tension – Symptoms are a lazy first shift or an incomplete last shift. This is easy to detect, when the cable is all the way out (in the high position) with no tension and it is loose and touching the frame, then there is a lack of cable tension. Just tighten the barrel adjuster (turn out or anticlockwise) to take up the cable slack and the problem should be solved.

Ghost shifting - This happens on full suspension bikes where the last section of cable between the frame and the derailleur is too short. As the suspension moves, usually at full compression, the cable is tensioned and initiates a shift. Other problems related to changing chain tension on some full suspension bikes can also affect shifting. So just bear these in mind if you encounter unexplained shifting problems. Sometimes setting up gears of a full suspension bike on a work stand may not be the same as setup on a bike under load.

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