Tiagra 28 Sprocket

[Hutch 75]

I have a 9 speed tiagra gearset on my Felt Z45 with a 11-25 cassette, i'd like to replace the 25 with a 28, well I am 44 and need all the help I can get, do I need to replace the whole cassette or can I replace just that gear, if so where would I get one from ?

Thanks

 

[Mark_Robson]

A far as I'm aware you will need to change the whole cassette and you may need to change the rear mech to a long model as well.

 

[jimboalee]

Ride hard, eat hard, sleep hard.

You'll soon get used to the 34 x 25 lowest on a 19lb bike....

 

[Hutch 75]

Ride hard, eat hard, sleep hard.

You'll soon get used to the 34 x 25 lowest on a 19lb bike....

I think you're probably right, it's only the big hills, well to me anyway, I'm struggling on and it is getting better as the weights coming off (20 stone to 15'10 since Sept) So i might just keep plodding away.

 

[RedBike]

Is there a cassette with a 28t sprocket?
The largest used to be 12-27.

 

[michaelrmgreen]

Megarange baby, 11-34. Knee friendly.

Edit : And here it is for only 37 of your earth pounds. : http://www.parker-international.co.uk/11448/Shimano-HG80-9sp-Cassette.html

Edit : edit : Or this : http://www.parker-international.co.uk/7402/Shimano-Deore-HG50-9sp-Cassette.html

 

[RedBike]

According to Google the Felt has a short cage rear mech and a compact chainset.

I'm not sure what gear range a short cage rear mech can cope but the combination of a 28t cassette and a compact chainset has got to be right at its limit.

You used to be able to just about fudge a long cage road mech to work with a 32t cassette but it was always a fudge and it never worked properly. I'm pretty sure a short cage road mech wont cope. For a cassette that large you need a MTB rear mech.

btw, When you change the cassette you will probably need to also fit a new chain. So you will need to budget for this.

 

[Hutch 75]

Thanks for the advise everyone, but looking at the amount of work it would entail I think I'll go with jimboalee's advice and stick it out, it really is only the bigger hills that I'm struggling on and coming from a MTB with a granny ring it's a bit of a shock to the system . I can now do hills that I couldn't do six months ago so lets just hope the improvement carries on !

 

[baznav]

Sram do 11-28 cassettes the short cage rear mech will work but in the 28 the top jockey wheel will rattle against the 28 cog, shimano is only built to cope with a maximum 27 top cog.
The new shimano rear mechs such as new dura ace, ultegra and 105 are now built to run with 11-28 cassettes.

 

[aberal]

Anyway, it doesn't really matter how low a gear you've got - you'll always, always at some point, somewhere, on some hill, find yourself looking for a gear lower than your lowest.

 

[PpPete]

Anyway, it doesn't really matter how low a gear you've got - you'll always, always at some point, somewhere, on some hill, find yourself looking for a gear lower than your lowest.

Especially if you are a softie southerner like me !
FWIW my medium cage mech copes OK with 42 Tooth total difference (50-38-26 Front, 12-30 rear) even though Shimano say it's rated for 22T max at front and 37T total difference.

 

[Nick_B]

The biggest few cogs are joined together on the Tiagra cassette so I don't see how you could change only the 25.

 

[PpPete]

You can grind off the heads of the rivets that hold the biggest sprockets together. Then you can have a pile of loose sprockets & spacers that you can re-install / replace how you want. However the "shifting ramps" may not match up if you swop in a sprocket from a different cassette.
In my experience that's no biggie as the shifting is only slightly less smooth.

 

[Fattman]

Anyway, it doesn't really matter how low a gear you've got - you'll always, always at some point, somewhere, on some hill, find yourself looking for a gear lower than your lowest.

Ah yes, the 'dead man's click' as we call it in our house.

I got me a SRAM 11-28 to go with my Tiagra 9-speed, but I replaced the rear mech with an Ultegra SL medium cage (sale item!) at the same time (I'd bent the original). This was with 50/34 up front. Have to say (a) the big hills got much easier and ( the Ultegra mech is *really* snicky and nice! All-in-all it was a fair cash outlay, but prob. the best 'upgrade' I've enjoyed after a new pair of wheels.