Originally Posted by
dsbrantjr
Unfortunately, rear derailleurs have a habit of getting bumped, often without the owner's knowledge e.g. parked, so I use them. Chain catcher up front, too. Belt and suspenders work for me.
It takes a whole lot more to bend a derailer hanger than just "getting bumped", especially enough to cause the derailer to shift over into the spokes
Originally Posted by
grizzly59
One time your chain gets wedged into the spokes of your really nice wheel and the dork disc is cool again
Situational awareness is the key. A bent derailer will give some indication that there is something wrong before you shift the bike into the spokes. The shifter and derailer don't shift a crisply as they should or the chain makes noise when a derailer is bent. On the other hand, if you feel the chain slide over into the spokes, you shouldn't mash down on the pedals.
Most of the time that a dork disc is needed is when someone wants to "adjust" their bike because it isn't shifting properly so they get out the screwdriver and start twisting screws without understanding what those screws really do. Once misadjusted, the limits are a bit difficult to set again...especially if you have no idea what you are doing in the first place.
99.99999% of all shifting problems are related to cables and there is one "screw" that should be adjusted to fix that...the barrel adjuster. If bike shops would explain to people that the limit screws don't need to be adjusted or if they came with security heads or were just filed off, it would fix a whole lot of problems.