How do you adjust derailleur gears on a Schwinn ranger mountain bike?

Answer 1

Put the chain on the smallest cog (gear) and tighten the cable snug. The "takeup slack" knob on the front of the derailer cable should be set so that it will only make the cable tighter. This is so that, when we are in the smallest gear (also called the highest gear) shifting the gear will pull it tighter and cause the derailer to push the chain on the larger cogs (or lower gears). With the shifter in it's tightest setting (having pulled the cable as tight as possible) we are in the lowest gear.

In some cases the chain may fall off the smallest gear, or go past the largest gear. This is what the "limiting screws" are for, they limit the range so that we don't go past the outside gears. To discover which screw must be adjusted is easy. Let's say we are going

past the largest gear. The screw that is tight against the end is the one that needs to be loosened a little (because we are pulling the chain past the end of the range of gears). If we were going past the smallest gear then the screw at it's limit wasn't tight enough to stop the chain before it came off.

This adjustment process is basically the same for the front derailer, of course the size of the gears front and back has the opposite effect, but this is not important in how to adjust the range really.

FYI: There are certain gear combinations that are not supported. For example if you put the chain on the largest front gear (chainring) you are saying, "I want to be in the

highest gear", and if you also put the rear of the chain on the largest gear in the back you are saying, "I want to be in the lowest gear". There isn't enough chain length to

effectively be in this position (although it might be possible) so the chain will rattle, in

effect trying to tell you "this isn't a good idea".
Depends on what's wrong with it. www.bicycletutor.com, www.parktool.com and www.sheldonbrown.com are three nice sites to turn to for help
There's a high limit screw, a low-limit screw, an angle adjustment (AKA b-screw) screw, a barrel adjuster on the casing for the shifter cable and a clamp screw for the cable on the derailer.

If it's been shifting OK before but isn't ruinning clean anymore, a few turns of the barrel adjuster will usually do the trick. If it's overshifting off the innermost/outermost sprocket, tweak the limit screw.

I'll add a link which gives more detail.

Answer 2

Release shifter cable by the clamp. Undo the screws at the center of the pulley bearings to open the cage. This'll allow you to remove the chain. Unbolt derailer from hanger. Bolt new derailer to hanger. Open cage, fit the chain. Hook up shifter cable. Adjust shifting. Done!

Keep in mind that not all derailers have the same actuation ratio. Make sure you buy the right one.

Answer 3

Too much to answer here, head over to www.bicycletutor.com, www.parktool.com or www.sheldonbrown.com and I'm sure you'll be able to find an answer there.

Answer 4

Depends on what's wrong with it, which is too much to be covered here. Head over to www.parktool.com/repairs, www.bicycletutor.com or www.sheldonbrown.com to read up on bike faults and fixes.