7S /8S Bicycle Rear Derailleur

How do I check the position of the Bicycle Rear Derailleur and adjust it to ensure it matches the chain?

Checking the position of your Bicycle Rear Derailleur and adjusting it to ensure it matches the chain is an important part of bicycle maintenance and adjustment. Here are the detailed steps to do this:
Check rear derailleur position
Look closely at how the rear derailleur matches the chain. When the chain switches between different cassettes, the rear derailleur should be able to accurately move the chain to the corresponding position, and the appropriate tension should be maintained between the chain and the cassette.
Check whether the rear derailleur deviates from its normal trajectory. If the rear derailleur wobbles or shifts during shifting, it needs to be adjusted.
Adjust rear derailleur position
Use a special adjustment tool, such as a screwdriver or Allen wrench, to adjust the limit screw on the rear derailleur. Limit screws are usually located on either side of the rear derailleur and are used to limit the position of the chain on the largest and smallest cassettes.
Adjust the limit screw as needed to change the rear derailleur's range of motion. If the chain is easy to fall off on the largest flywheel sprocket, you can appropriately increase the tension of the limit screw on the largest flywheel side; conversely, if the chain is easy to get stuck on the smallest flywheel sprocket, you can reduce the tension on the limit screw on the smallest flywheel side.
When adjusting the limit screw, pay attention to maintaining the overall balance and stability of the rear derailleur to avoid deflection or shaking.
Fine-tuning rear derailleur and chain matching
Fine-tune the rear derailleur to chain match by adjusting the tension on the shift cable. The tension of the shift cable can be adjusted using the fine adjustment screw on the derailleur.
Turn the fine-tuning screw counterclockwise to loosen the shift cable tension, allowing the rear derailleur to move toward the small sprocket of the flywheel; turning it clockwise will increase the shift cable tension, causing the rear derailleur to move toward the large sprocket of the flywheel.
During the adjustment process, carefully observe the matching between the chain and the flywheel sprockets to ensure that the chain can smoothly switch to each flywheel sprocket without skipping teeth or chain jamming.
Please note that before making any adjustments, it is best to consult your bike's owner's manual or related maintenance guide for adjustments and precautions for your specific model of bike. If you are not sure how to make adjustments, it is recommended to seek help from a professional bicycle mechanic.
Finally, once adjustments are made, be sure to do a few shifting tests to make sure the rear derailleur is a good match to the chain and the shifting system is working properly. This ensures better shifting and riding experience during riding.