Refurbishment help needed (PLEASE)

[ernestevo]

Hello,

Can someone please clarify that I am on the right track regarding my bike restore.

I have a second hand Orbea Carpe that I am in the process of restoring and I need some help to clarify which parts I need to purchase (Bike link below). The previous owner had experienced some troubles during a ride resulting in the rear derailleur and chain being destroyed / twisted. This also damaged the rear break cables. The rear cassette is 9 speed, however the destroyed rear derailleur is a 10 speed. I will also be putting the bike in for a general service to have the rear break cable replaced prior to first ride.

(http://www.orbea.com/img/products/product/large/ZC51TTCC-F4-SIDE-CarpeH40_USA.jpg)

Question: If I purchase a 10 Speed Rear derailleur (Shamano Tiagra RD 4601), a nine speed chain (Shimano Dura Ace or XTR 9 Speed Chain) and leave my nine speed rear cassette, will the following work? Or do I need 9,9,9 rather then 10,9,9?

Destroyed parts:
Chain (112 rivets);
Shimano Tiagra RD 4601 rear derailleur.

Proposed new parts:
Shimano Dura Ace or XTR 9 Speed Chain;
Shimano Tiagra RD 4601 rear derailleur.

I appreciate your time and thanks,

Tom