How can a rear mech be 8,9 or 10 speed?

[Peteaud]

I know the movement is from the shifter so the rear mech will only move as far as the shifter disctates, but what about the stops?

! have a 9 speed rear mech, but the new one says 8,9 or 10 speed. So how do you set the stops?

It must be even worse for 8 speed.

 

[mcshroom]

The stops are in the same positions pretty much. 9sp mechs work 8sp gears, I have that setup on two different bikes. As Shimano have changed the cable pull for 10sp MTB rear mechs, some tourers are now using 9sp rear mechs with a 10sp setup as well.

 

[Peteaud]

So if i replace my old one (Tiagra) with a new 10 speed tiagra one for my 9 speed (along with new 9 speed chain) all should work.

 

[mcshroom]

Should do

 

[Peteaud]

thanx