Tiagra 10 speed

[baggytrousers]

I've got a Defy 2 with Tiagra 9 speed and need to replace the rear derailleur. Will the new 10 speed derailleur still be compatible with my 9 speed shifters and cassette?

 

[Peteaud]

put on a 105

http://www.merlincycles.com/bike-sh...5-5700-rear-derailleur-short-cage-silver.html

or 9 speed tiagrahttp://www.google.co.uk/products/ca...=X&ei=SKrXT9-JN8nj8AOsqrSGAw&ved=0CJIBEPMCMAE