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Cassette advice
Posted: 8 Jul 2024, 8:51pm
by cc1085
I recently bought a Giant Defy 1 Aluxx for little money. Half the weight of my regular bike and great to ride. The current Shimano cassette at 11-25 is for a much younger person than me. Can I change this cassette for 11-34 without having to change the derailleur etc.
Thanks
Thom
Re: Cassette advice
Posted: 8 Jul 2024, 9:27pm
by Barrowman
Can you post a picture of your derailleur ?
You might have a 'medium' and you will need a 'long' for the bigger cassette .
Other Giant Defy owners might be able to help here?
Re: Cassette advice
Posted: 8 Jul 2024, 9:35pm
by cc1085
Barrowman wrote: ↑8 Jul 2024, 9:27pm
Can you post a picture of your derailleur ?
You might have a 'medium' and you will need a 'long' for the bigger cassette .
Other Giant Defy owners might be able to help here?
Thank you very much for such a quick reply. I'll check it all tomorrow.
Thom
Re: Cassette advice
Posted: 8 Jul 2024, 9:39pm
by Paulatic
I suspect it might have a short cage with a max of 28. 30 at a push maybe.
Re: Cassette advice
Posted: 8 Jul 2024, 10:01pm
by rogerzilla
(Looks sheepishly at 13-21 cassette on the Eddy Merckx)
Re: Cassette advice
Posted: 8 Jul 2024, 11:38pm
by Cyclewala
I have a 2010 Defy with 11-25. It’s got a short cage derailleur so 11-28 (possibly 30) is the largest I can go. But, my chainset is Tiagra Compact double and with limit screw adjustment, I can switch it to a triple (with the addition of a middle ring). This was the 4500 series Tiagra (when they were 9 speed).
If you have the same, this might be the best solution.
Re: Cassette advice
Posted: 9 Jul 2024, 12:02am
by Eyebrox
The derailleur needs to be the GS version rather than SS. It will have either letter code on it. The SS will stretch to 30 teeth although Shimano, I think, recommend 28 maximum. GS will cover up to 34 and give you peace of mind. You will need a longer chain if the one you have is cut to fit a 25 cassette.
Re: Cassette advice
Posted: 9 Jul 2024, 1:15pm
by mattsccm
I know from personal experience that a short mech will cope with a 32 t sprocket if your inner chain ring is no more than 34 t and you don't cross chain to the outer ring.
Re: Cassette advice
Posted: 9 Jul 2024, 3:20pm
by CyberKnight
rogerzilla wrote: ↑8 Jul 2024, 10:01pm
(Looks sheepishly at 13-21 cassette on the Eddy Merckx)
reminds me of my 1st road bike , a gas pipe special i fitted aero bars and 13-19 freewheel
Re: Cassette advice
Posted: 10 Jul 2024, 4:45pm
by gxaustin
Cyclewala wrote: ↑8 Jul 2024, 11:38pm
I have a 2010 Defy with 11-25. It’s got a short cage derailleur so 11-28 (possibly 30) is the largest I can go. But, my chainset is Tiagra Compact double and with limit screw adjustment, I can switch it to a triple (with the addition of a middle ring). This was the 4500 series Tiagra (when they were 9 speed).
If you have the same, this might be the best solution.
Wouldn't you need a new LH shifter? It would be cheaper to buy a longer GS mech.
Re: Cassette advice
Posted: 10 Jul 2024, 4:48pm
by gxaustin
mattsccm wrote: ↑9 Jul 2024, 1:15pm
I know from personal experience that a short mech will cope with a 32 t sprocket if your inner chain ring is no more than 34 t and you don't cross chain to the outer ring.
Trouble is you have to be very aware of which ratio you are in. Lose count and it could be expensive/serious.
I'd advise against that and buy a long GS derailer
Re: Cassette advice
Posted: 11 Jul 2024, 8:54am
by Cyclewala
gxaustin wrote: ↑10 Jul 2024, 4:45pm
Cyclewala wrote: ↑8 Jul 2024, 11:38pm
I have a 2010 Defy with 11-25. It’s got a short cage derailleur so 11-28 (possibly 30) is the largest I can go. But, my chainset is Tiagra Compact double and with limit screw adjustment, I can switch it to a triple (with the addition of a middle ring). This was the 4500 series Tiagra (when they were 9 speed).
If you have the same, this might be the best solution.
Wouldn't you need a new LH shifter? It would be cheaper to buy a longer GS mech.
Sorry, should have clarified. I have Tiagra shifters and derailleurs. The LH shifter is a triple but came set up as double. So, with adjustment of front derailleur, I could convert it to triple.
Re: Cassette advice
Posted: 15 Jul 2024, 7:52am
by djnotts
Will not a simple mech extender do the job? Usually do.
Re: Cassette advice
Posted: 15 Jul 2024, 9:20am
by cycleruk
djnotts wrote: ↑15 Jul 2024, 7:52am
Will not a simple mech extender do the job? Usually do.
Possibly but the short cage mech' won't have enough wrap to take up the longer chain.
It would work but the chain would hang when on small-small with the chance of it jumping off.
A longer chain will be needed to accommodate the new big-big arrangement.
Re: Cassette advice
Posted: 18 Jul 2024, 3:07pm
by cc1085
Thanks Everyone for all that advice. I've been quoted €200 including fitting for cassette,derailleur and chain. That's more than I paid for the bike so I'll either have to get fitter or find another way.
Thom