Bigger big sprocket on Giant road bike

[User]

 

[themosquitoking]

I've got a 12-30 on my defy. 105 mech though.

 

[MikeW-71]

He might get away with a 30t on the current mech. Change to a longer cage Sora mech (pretty cheap) to go to 32t. Chain will probably need to be lengthened a link or two.

 

[jowwy]

Ive got a 32 on my 105 rear mech

 

[Herzog]

As above, 30T should be fine (providing the chain isn't already on the short side).

Edit: May need to adjust b-screw slightly.

 

[sreten]

Hi,

Typical chain lengths on commercial bikes are usually bang in the
middle of the maximum and minimum chain length for the set up.

Minimum is for racers due to weight, and maximum give you
a longer chain life. It is a mistake to assume minimum length.

Both my bikes have what I'd call "medium" length and would
easily encompass increasing 28 on both to 30 or 32 on both.

rgds, sreten.