Einstellen der Schaltung: Unterschied zwischen den Versionen

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==Einstellen des Schaltwerks (hinten)==

Before you try to adjust your rear derailer, you should really make sure it isn't bent. The rear derailer is the most fragile and exposed part of a bicycle, and they are always getting bonked.

#*Height<br>        of the front derailer is a principal factor in how well it will shift. Manufacturers commonly recommend 2 mm clearance between the bottom of the outer cage plate and the teeth of the large chainwheel. This is a bit of an oversimplification. Best performance will result from the very lowest position that still just barely keeps the cage from hitting the chainwheel teeth. The lower you can get it, the better it will shift, and the less you will need to trim the front derailer.

#Derailer/Chainwheel Mismatch<br>    To get the front derailer as low as possible, the curvature of the outer cage plate has to match the curvature of the largest chainwheel.<br>    If you use a larger chainring than the derailer was designed for, the rear of the cage will hit the teeth of the big chainring before the front of the cage gets low enough to provide crisp shifting without the need for trimming.<br>    If you use a smaller chainring than the derailer was designed for, it will shift OK, but you'll have to do a fair amount of trimming, due to the rear of the cage being higher than it should be, so that the chain crosses through it farther back.<br>    Lately I've started modifying front derailers for improved shifting with larger rings. I have a Shimano RSX front derailer on a bike with 50/38/28 Biopace (the sweep of a 50 Biopace is comparable to that of a 52 round.) The RSX front derailer works great on its intended 46/36/26 setup, but the cage doesn't match the curve of the larger chainring. In a couple of minutes with a grinding wheel, I removed a good bit of metal from the bottom rear of the outer cage plate, and a bit from the bridge section where the inner and outer cage plates connect at the back. This made the derailer match the curvature of the larger chainwheel, and allowed me to set it low enough to provide good chain control. This setup now works fine with an STI indexed shifter that doesn't permit "trimming" the front derailer.

#Low-gear limit stop.<br>    The low-gear limit stop stops the derailer from shifting past the smallest chainwheel and throwing the chain onto the bottom bracket shell. If the stop is too loose, the chain will fall off when you try to downshift to the small chainwheel. If too tight, you will find it difficult or impossible to shift down to the small chainwheel.<br>    On older front derailers, the low-gear stop is the one closer to the frame. Many newer designs reverse this position for reasons relating to the mechanism used.<br>    The basic adjustment for the low-gear stop is to set it so that the chain just barely clears the inner plate of the cage when the lowest gear (small front, large rear) is selected. This will usually be the best position for double-chainwheel setups, and will permit the use of most or all of the rear sprockets with a minimum of trimming.<br>    For triple chainwheels, it will sometimes be necessary to adjust the low-gear stop a bit looser, so that the outer plate of the derailer can travel far enough to knock the chain off of the middle ring.

#*Anti-derailment devices<br>    In some instances, you may find that one adjustment of the low-gear stop causes the chain to derail past the small chainring, but a tighter setting results in slow downshifting to the small ring.<br>    In such cases, a good, if inelegant, solution is sometimes to install an anti-derailment device that clamps to the seat tube. These products, such as the 3rd Eye Chain Watcher ® and the N-Gear Jump Stop ® set up a barrier preventing the chain from overshooting the small ring, no matter how loose the low-gear stop is set. This allows the low-gear stop to be set to allow the derailer to move farther inboard for faster, more precise shifting, even under some load. These devices can often save the day when extra-wide range gearing is used on a mountain bike or tandem.

#High-gear limit stop<br>    The high-gear limit stop is pretty straightforward. It should be set so that the chain almost rubs on the outside plate of the front derailer cage when the bicycle is in its highest gear (large front/small rear). This will reduce the need for trimming as you shift the rear derailer.<br>    If the shift to the large chainwheel is slow, make sure that you aren't pedaling too hard: front upshifting requires being ready to have the cranks slow down when the shift takes place. If the shift is unreliable even when you are pedaling lightly, you may be able to improve it by loosening the high-gear stop a bit. If you do so, check to make sure that the derailer cage is not moving so far out that it can be struck by the crank as it goes by.<br>    Sometimes front upshifting may be improved by rebending the front edge of the inner cage plate outward a bit. This may be done with an adjustable wrench. This is rarely necessary on modern front derailers, but used to be a very common trick on older, cruder designs.