Shimano Tiagra rear cassette .

[Doug.]

Hello.
Re. above my bike has the above 10 speed group/chain set.
I wish to change from the present 11 to 28 rear cassette to a 12 to 30.
The big sprocket for easier hill climbing(too many steep hills where I live)
Will I also have to change the rear mechanism ?
I am not sure if the r/mech. is short,medium or long.
Will be very grateful for any advise,thank you.
Doug.

 

[Doug.]

I forgot to mention it has a compact crank.

 

[Peteaud]

You should be able to swap it straight over. The rear mech may need a tweek tho.

Chain length should be ok also.

 

[Cycleops]

Your Tiagra mech is a long cage so you can swap the cassette without any probs. The only thing is the difference is going to be barely perceptible.

 

[Doug.]

Thank you all for the replies.