Ultegra 6500 or 6600

[rydeon]

I'm building a 9sp bike (salsa campeon)and budget limits me to an Ultegra rear derailler. Is there much difference (besides $30.) between the 6500 and the 6600 models? I'm using a 105 up front.
Thanks for any experience observations!

 

[capwater]

I'm building a 9sp bike (salsa campeon)and budget limits me to an Ultegra rear derailler. Is there much difference (besides $30.) between the 6500 and the 6600 models? I'm using a 105 up front.
Thanks for any experience observations!

6500 is the 9 speed model, 6600 is the 10 speed. Either will work with 9 or 10 speed drivetrain.

 

[Doctor Morbius]

6500 is the 9 speed model, 6600 is the 10 speed. Either will work with 9 or 10 speed drivetrain.

Agreed. It is the shifter that will determine how many gears the rear Der will use. Why not go with 9 speed 105 if you're on a tight budget? Chances are the 10 speed 105 will cost more than the 9 speed Ultegra.