More gears?

[Ajax Bay]

@S-Express "You can swap the cassette for 12-28 with no other changes." I recommend that the OP does this first and see what difference they experience.

How much of a difference is this likely to make?

Have a play with this gear calculator (click will give you 50-34 compact and 9sp 12-25 sprocket). If you fit a cassette with a 28t largest (vice a 25t) you will gain exactly 12% gearing. This means in practice that if you can keep balanced on a cadence of 40 (say) you will climb 12% more slowly and therefore need (very roughly) less power. Still got to turn the cranks. HTH

 

[jefmcg]

Should be no problem putting an 11-32 on.

I did this on a friend't Giant Avail recently with no problems.

In 2012, Giant started putting 30 teeth cogs on Defy/Avail. So that would not have been a big step if it was more recent the the OP's 2011 model.

 

[Spiderweb]

As S-Express said a 28T will work without a longer cage rear mech. I had a 53/39T on the front and required lower gears so had the rear swapped from 25T to 30T, a longer chain was required but the existing short cage rear mech was fine.

 

[Dogtrousers]

In 2012, Giant started putting 30 teeth cogs on Defy/Avail. So that would not have been a big step if it was more recent the the OP's 2011 model.

I don't remember offhand exactly what the cassette that I removed was, definitely wasn't a 30T max. It wouldn't really have been worth the trouble for the extra 2 teeth.

The bike was bought second hand sometime in 2015 I think. I have no idea what year it was originally.

Edit. Just gone thru my emails. It was 12-26. I swapped the RD for a longer cage one for the princely cost of about £18.

 

[chriscross1966]

I'm willing to bet that it will be easier and cheaper to do those mods to your old-fashioned penny-penny safety bike than it was to go from 3-speed to 11 on my sleek modern-designed folder :-)

 

[bondirob]

Buy a 32t cassette they aren't expensive.
If you have a short cage derailleur it will work just screw the 'b' screw in.
The manufacturer and no doubt your lbs will tell it won't be big enough but it is.
You'll also need a longer chain.
It'll cost less than £30 and will transform the way you go up hills.