Is a 10 speed rear mech compatible with 9 speed shifters?

[Tomba]

As per title. Is a 105 5700 (10 Speed) rear mech compatible with Tiagra 4500 (9 Speed) shifters?

I only ask as I saw the 105 rear mech advertised as 8/9/10 speed.

 

[Svendo]

Yes. That is the combination on my commuter bike (except it's a 5600 rear derailleur).

The 9 and 10 speed derailleurs both have the same amount of side to side shifting movement for a given cable movement (pull ratio), and move across the same overall distance. In fact they'll cover a lot wider distance than necessary and it is narrowed to the necessary range by the limit screws. This is to accommodate variations in the lateral position of the derailleur relative to the cassette above it on different frames, and with different wheel hubs.

The difference between 9 and 10 speed is the distance from top gear to bottom gear is divided into 9 steps and 10 steps (or cogs) respectively. The shifters pull the necessary amount of cable, which is a bit more for 9 speed, as there's one less step than 10 speed.

 

[bobones]

Yes, it will work fine. The mech just moves according to the cable pull of the shifters and doesn't care how many clicks there are and a nine speed chain will run though the mech without issue.

 

[Tomba]

Yes. That is the combination on my commuter bike (except it's a 5600 rear derailleur).

The 9 and 10 speed derailleurs both have the same amount of side to side shifting movement for a given cable movement (pull ratio), and move across the same overall distance. In fact they'll cover a lot wider distance than necessary and it is narrowed to the necessary range by the limit screws. This is to accommodate variations in the lateral position of the derailleur relative to the cassette above it on different frames, and with different wheel hubs.

The difference between 9 and 10 speed is the distance from top gear to bottom gear is divided into 9 steps and 10 steps (or cogs) respectively. The shifters pull the necessary amount of cable, which is a bit more for 9 speed, as there's one less step than 10 speed.

Yes, it will work fine. The mech just moves according to the cable pull of the shifters and doesn't care how many clicks there are and a nine speed chain will run though the mech without issue.

Thanks very much guys

 

[User482]

Whilst road 9 and 10 speed is generally compatible, be careful with mtb: a 10 speed shimano mtb rear mech will not work with 9 speed mtb shifters.