Shimano Alivio T4000 - 9 Speed SGS Rear DerailleurShimano Alivio T4000 9 Speed SGS Rear Derailleur The Shimano Alivio RD T4000 is a 9 speed rear derailleur for use on touring bikes. It has a lower profile than its predecessor and, thanks to the pantograph double servo mechanism, ensures optimum shifting with minimal operating forces. The inner and outer cages of the rear derailleur are made of robust steel. RD T4000 is available in silver and black. Quiet, precise, smooth running shifting function