9 Speed Tiagra RD and cassette range

[ManxJason]

Hello I'd like to fit either a 12-30 or 12-32 cassette to my bike, which currently has a 12-27.

Looking at this photo are you able tell if the 12-32 would fit? I have no idea how to tell what length cage I have.

P.s I can push the deeraileur back with my hand and it frees up a lot more space between it and the cassette

Thanks

 

[smokeysmoo]

The cassette will fit no problem, it's the rear mech that will determine if it can take a 32.

I personally can't tell from that pic what your mech is, but you need a medium cage like THIS one to handle a 32.

 

[ManxJason]

Thanks. Looking at the photo mine looks identical but I guess the only way to tell would be measuring. I'll go for the 32. If the mech doesn't play ball then a RD is pretty cheap anyway. Thanks mate

 

[arch684]

an older bike i owned had 9 speed tiagra shifters and a 105 medium cage rear mech and a 32 cassette worked great

 

[Peteaud]

Depends on the bike (hanger length), most will tale the 30T without issue, 32T some will, most will be at the very limit.

 

[arch684]

medium cage will work fine on a 32 cassette

 

[TheDoctor]

I'd try it and see. A new rear mech isn't that pricey if you end up needing one.
My old 105 rear mech is rated for a 27T sprocket, but works* on a 32T.

*For somewhat noisy values of 'works'

 

[montage]

12-30 works fine on my ultegra short cage.

There is nut you can adjust to move the derailleur back to accommodate if you need to