Replaced a Shimano 105 nine speed derailleur worn out after 20 years of all year round commuting and general use as a winter bike. The Sora RD-R3000 has a larger capacity, useful as cassettes have got larger and being older need lower gears! It was a straight swop out of the box, the most time consuming part of the task was cleaning the rest of the drive train. I didn't even need to tweak the cable tension.