Rear Derailler for a 9-speed with a 32 tooth cassette
02-13-16, 01:55 AM
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Rear Derailler for a 9-speed with a 32 tooth cassette
I've been riding for more than 60 years and am starting to find steep hills very challenging. The largest cassette cog on my 9-speed Cannondale Carbon Synapse road bike has 27 teeth. I would like to install a cassette with a 32 tooth cog. But I can't find a 9-speed road bike rear derailler with a longer cage to replace the Ultegra SS that is on there. Would a 10 or 11-speed medium-cage RD work?
02-13-16, 04:33 AM
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The fairly standard answer for this, is to use a 9 speed Deore M591, this has more than enough capacity for a 11-32 cassette.
02-13-16, 10:06 AM
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10/11-speed MTB deraiileurs won't work with your current shifters - these have a different cable pull ratio.
The 9-speed RDs are what you should be after.
Plenty of them are available.
As to the Medium cage ("GS" in Shimano-speak) - yes, it can work, but only if you you are running a double chainring on the front and make a few mental adjustments.
It is a matter of RD capacity. Shimano's GS have 33-tooth capacity, and the SGS - 45-tooth, meaning that this is the total of chainwrap they are designed to handle. In reality, you can exceed this in a clever way.
I have been running a Shimano XT M771 GS RD for years with a front double 50/34, and 12-32 in the rear, while absolutely avoiding the small-small and the big-big combinations. This provides a very nice crisp shifting, although in theory the setup exceeded the 33t capacity of the GS
(50-34)+(32-12)=36
Again, this was run with a chain barely long enough to enable me shifting into the big-big (if done by mistake), and self-discipline about the cross-chained combinations.
Having said this, I am close behind you on age, and the hills where I ride have no mercy, especially when I carry light loads for a weekend trip on my fast bike.
For this reason, I installed a 12-36 cassette, which did not work so well with the GS RD - the shifts are a bit lazy when getting close to the small-small combo due to very little tension in the chain. This is why I am replacing it with a SGS next week.
One thing about the M771 - it does not have a barrel adjuster built in, meaning that you can use it only if you have an adjuster on your downtube cable stop or in-line adjuster elsewhere. Otherwise, look up the Deore M951 as jimc101 already suggested. Or get a Jagwire Rocket adjuster and shove it in the RD.
The 9-speed RDs are what you should be after.
Plenty of them are available.
As to the Medium cage ("GS" in Shimano-speak) - yes, it can work, but only if you you are running a double chainring on the front and make a few mental adjustments.
It is a matter of RD capacity. Shimano's GS have 33-tooth capacity, and the SGS - 45-tooth, meaning that this is the total of chainwrap they are designed to handle. In reality, you can exceed this in a clever way.
I have been running a Shimano XT M771 GS RD for years with a front double 50/34, and 12-32 in the rear, while absolutely avoiding the small-small and the big-big combinations. This provides a very nice crisp shifting, although in theory the setup exceeded the 33t capacity of the GS
(50-34)+(32-12)=36
Again, this was run with a chain barely long enough to enable me shifting into the big-big (if done by mistake), and self-discipline about the cross-chained combinations.
Having said this, I am close behind you on age, and the hills where I ride have no mercy, especially when I carry light loads for a weekend trip on my fast bike.
For this reason, I installed a 12-36 cassette, which did not work so well with the GS RD - the shifts are a bit lazy when getting close to the small-small combo due to very little tension in the chain. This is why I am replacing it with a SGS next week.
One thing about the M771 - it does not have a barrel adjuster built in, meaning that you can use it only if you have an adjuster on your downtube cable stop or in-line adjuster elsewhere. Otherwise, look up the Deore M951 as jimc101 already suggested. Or get a Jagwire Rocket adjuster and shove it in the RD.
Last edited by IK_biker; 02-13-16 at 10:12 AM.
02-13-16, 02:05 PM
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I just ordered an M591 and an 11-32 from JensonUSA. Thank you both for your advice.
