Originally Posted by
Joe G
If you want to lay as little money as possible. If you can get 105 replace it with 105, it's cheap and works well. The last few friends of mine who had Dura Ace and Ultegra 10 speed stuff, were replaced with Tiagra because 105 and up are now 11 speed.
Good Luck
the new Tiagra 10spd shifters don't work with 7900/6700/5700 10speed derailleurs.