Replacing a cassette sprocket



alig

New Member
Sep 21, 2006
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I have a Shimano HG-50 9 speed 12-25 cassette
Rather than buy a new cassette, I'd like to know if I can remove the 25T sprocket and replace it with an 11T sprocket to make a 11-23

If so, can anyone recommend a website here in Australia where I can buy cassette spares.
 
Dec 30, 2007
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alig said:
I have a Shimano HG-50 9 speed 12-25 cassette
Rather than buy a new cassette, I'd like to know if I can remove the 25T sprocket and replace it with an 11T sprocket to make a 11-23

If so, can anyone recommend a website here in Australia where I can buy cassette spares.

That cassette can be disassembled, made all loose. Yes, you can remove the 25t(and the spacer), add a 11t and a 11t lockring(smaller) and then go ride.

In the colonies, can't help you with a bike shop.
 

alfeng

Well-Known Member
Jul 23, 2005
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alig said:
I have a Shimano HG-50 9 speed 12-25 cassette
Rather than buy a new cassette, I'd like to know if I can remove the 25T sprocket and replace it with an 11T sprocket to make a 11-23
Do you really want an 11t cog?

Even if you're changing to a "compact" crankset, short of having legs like Robbie McEwen, about the only reason for the average rider to have an 11t cog on a ROAD cassette is if s/he is doing a lot of riding on mountain roads, or equivalent (i.e., long descents).

N.B. If you were to ONLY buy an 11t cog + 11t lockring (the diameter is smaller ... it can be used with a 12t cog, of course), then you will still need a DIFFERENT 12t cog because the smallest cog on the stack is capped & cannot slide all the way onto the freehub body ...

Consequently, IMO, your least expensive option for an 11t cog + 11t lockring is to buy an 11t-32t LX cassette ... cannibalize the two components you want + the LX's 12t cog (or, whichever size SECOND cog you want) ... and, put the 12t, 13t & 25t from your road cassette in a baggie with the rest of the LX cassette.

BTW. On some of the Shimano's second tier cassettes, the portion that is pre-assembled as a unit are held together with a RIVET and in some cases a BOLT which has a 1.5 (?) mm Allen head. If the cassette is riveted, then you will have to grind the head (on the largest cog) off ... if it is bolted together, then unbolt it. UNLESS you are using a wheel which has an alloy freehub body, the bolts/pins which hold the larger cogs of the LX-or-105/whichever cassette are NOT necessary & are primarily to facilitate sliding the cogs-and-spacers onto the freehub body.
 

alig

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Sep 21, 2006
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sounds like a massive pain
will probably just buy a new cassette
 

alfeng

Well-Known Member
Jul 23, 2005
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alig said:
sounds like a massive pain
will probably just buy a new cassette
Well, I reckon that removing the bolts that hold the cogs together is about as difficult as opening three bottles of ketchup/soda/whatever & then putting the bottle caps back on ...

If the cassette's cogs were riveted, then you'll probably need a grinder, but you could just chisel/file the heads off (NOT recommended), too. The degree of difficulty is about equal to opening up a bottle of wine with a cork screw (vs. boxed or screw top) ... that is, sometimes you need a specific tool, but obviously people have jammed the cork into a wine bottle when they didn't have a cork screw.

Allow 3-to-15 minutes to swap the cogs (the time will be dependent on your manual dexterity & which tools you have) AFTER you remove your 12-25 cassette from your rear wheel.

AFTER you find out how much a DA-or-Ultegra cassette costs, you can reconsider buying-and-cannibalizing an LX cassette -- even Vegans can cannibalize a cassette!
 

curby

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May 9, 2006
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everything I read above seems correct... single cogs new from the dealer are expensive as is the lockring you will need. A used 11-23 is often sold because the user never uses the 11 & 12. If you find one of these on eBay for under $10- that is probably your cheapest option. You might end up with 'like new' 11 & 12t cogs, the lockring and some other usable cogs.

one other issue to think about is how much wear is on your chain/cassette and will mixing cogs exhibit any wear incompatibility. new cogs with an old chain or new chain and old cogs often skip under load.

good luck

all's'miles

curby
 

alig

New Member
Sep 21, 2006
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That's weird, I spend 99% of my time in 12T
I've found that jensonusa "sells" (no stock) 11T ultegra cogs and lockrings
My question is are these cogs and lockrings intercompatible (eg. ultegra lockring on HG-50 cassette and vice versa)
My second question is are all newer shimano freehubs the same? ie. can I replace a hyperglide cassette with a CS-6500
 

alfeng

Well-Known Member
Jul 23, 2005
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alig said:
That's weird, I spend 99% of my time in 12T
Geez! Are you speed skating during your off season?

You should probably set up a Single Speed bike.
alig said:
I've found that jensonusa "sells" (no stock) 11T ultegra cogs and lockrings
My question is are these cogs and lockrings intercompatible (eg. ultegra lockring on HG-50 cassette and vice versa)
My second question is are all newer shimano freehubs the same? ie. can I replace a hyperglide cassette with a CS-6500
Most of Shimano's freehubs have the same spline pattern -- the earliest Dura Ace freehub is not compatible + the early 8-speed freehubs have a threaded lockring ... otherwise, the only thing that you generally need to be concerned with is what "speed" the cogs & spacers belong to.
 

alig

New Member
Sep 21, 2006
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I'm not a high cadence rider
Still not sure if going from 12 to 11T is worth the hassle but thanks for the help, its nice to learn to service/upgrade your own bike
 

alfeng

Well-Known Member
Jul 23, 2005
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alig said:
I'm not a high cadence rider
Still not sure if going from 12 to 11T is worth the hassle but thanks for the help, its nice to learn to service/upgrade your own bike
The difference is HUGE ...

Imagine changing your large chainring to a ~57t if you currently have a 52t outer ring ... or, a ~58t if you've currently got a 53t, etc.

Depending on the terrain that a person encounters, it might be worth it if the largest chairing was a 48t, or smaller.
 

curby

New Member
May 9, 2006
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Don't forget the 12t cog you have won't work in the 2nd position.

he compatibility between cogsets is not usually a problem... i have put DA or Ultegra cogs in the middle of non-matching cassettes without any trouble. Also SRAM 11t & 12t on a Ultegra cassette. Shifting was not a problem.

all's'miles

curby
 

alienator

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Jun 10, 2004
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alig said:
I'm not a high cadence rider
Still not sure if going from 12 to 11T is worth the hassle but thanks for the help, its nice to learn to service/upgrade your own bike

An 11T cog is pretty limited in it's possible use. If you've got a lot of big, long, fast descents, and 11T can come in handy. If you're Tom Boonen it could come in handy in some sprints. Going with a 12-25 will give you an extra, more useful gear in the center of the cassette somewhere.

Lock rings? Dead cheap. eFlay has tons of 'em, as it does cassettes.