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Old 03-29-07, 12:55 PM   #1
serpico7 
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Lower geared cassettes - Century Special vs. custom Miche

I'm considering lowering my bike's gearing. Currently using a 50-34 crank with 12-27 cassette, and an Ultegra 6600 10 speed drivetrain (except for the compact crank).

I have narrowed down the various cassette options to the 9 speed Harris Century Special (13-30) or a 10 speed custom Miche cassette (13-29; to acheive this, I'd get a Miche 12-26, remove the 12, 13 cogs, add a 13 first position cog and a 29 last position cog).

Both should work with an Ultegra short cage derailleur in terms of max sprocket. Even with a 27t cog, the B-screw is pretty far unscrewed, so I think there's enough adjustability to fit a 30t cog. And the Ultegra short cage mech should be able to wrap enough chain for my setup (needs to wrap 33t to use small-small combo), but I avoid small-small anyway.

Pros/Cons of the cassettes (relative to each other):
Century Special
Pros: lower gear; pre-built
Cons: if 10sp shifter doesn't shift the 9sp cassette crisply, I'll need to either get a Shiftmate or a 9sp right-side shifter

custom Miche
Pros: 10sp, so shifting is likely to be great; gear spacing
Cons: limited to 29, which is not a huge jump from existing 27

I decided against mtn cassettes because the gear spacing is too wide, and I'd rather sacrifice an 11 or 12 cog than lose middle cogs. Similarly, the IRD 10sp cassettes are too wide and have small cogs I don't need.

Anything I'm missing? Thoughts?

As with so many things two-wheel-related, my understanding of the topic has been greatly augmented by Sheldon Brown's excellent articles.
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Old 03-29-07, 01:00 PM   #2
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I don't see how you could be happy with the shifting performance with anything other than a 10-speed Shimano compatible cassette. A 34/29 combination would be pretty doggone low. You should be able to climb a tree with that.

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Old 03-29-07, 01:08 PM   #3
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Quote:
Originally Posted by Al1943
I don't see how you could be happy with the shifting performance with anything other than a 10-speed Shimano compatible cassette. A 34/29 combination would be pretty doggone low. You should be able to climb a tree with that.

Al
Sheldon Brown claims that by using an alternate cable routing (http://www.sheldonbrown.com/dura-ace.html), you can mate a 10sp shifter with a 9sp cassette. Would love feedback from forum members who have tried this. I am definitely not willing to settle for merely serviceable shifting - I want good, crisp shifting.

As for the super-low gear, my knees aren't happy unless my cadence is over 75, and preferably, considerably higher.
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Old 03-29-07, 01:10 PM   #4
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I have an SRAM 12-26 and recently pulled out the 14t cog and put in a miche 29t cog. Works pretty good with my 105 short cage derailuer and compact crank with 50/34t rings. Only afew issues... I *accidentally* shifted into the 50/29 combo and essentially got the chain stuck with the rear derailuer fully extended... I was able to get it unstuck with afew grunts and some finessing but i think the rear derailuer is a bit tweaked even though it shifts fine still. Also, the upper jockey pulley teeth hit the 23t, 26t, and 29t sprockets when in the 34t chainring and pedaling backwards (forwards is no problem, but it's still kinda annoying).

I'm thinking i need a slightly longer chain to aleviate both problems which is something you'll want to consider if/when you get a new casette. (fortunately both my SRAM casette has only afew hundred miles on it while the chain has about 200% more miles so getting a new chain at this point really shouldn't cause any skipping/shifting issues due to mismatched wear). My only concern is to make sure i don't go with too long a chain that the rear derailuer can't fully tension the chain when in the small/small combo (though a bit of slack shouldn't be an issue since i'm usually already in the big ring by the time halfway through upshifting on the rear cassette...)
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Old 03-29-07, 01:16 PM   #5
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Best bet to size chain is big-big plus two links to prevent locking up the dérailleur.


Quote:
Originally Posted by Psydotek
I have an SRAM 12-26 and recently pulled out the 14t cog and put in a miche 29t cog. Works pretty good with my 105 short cage derailuer and compact crank with 50/34t rings. Only afew issues... I *accidentally* shifted into the 50/29 combo and essentially got the chain stuck with the rear derailuer fully extended... I was able to get it unstuck with afew grunts and some finessing but i think the rear derailuer is a bit tweaked even though it shifts fine still. Also, the upper jockey pulley teeth hit the 23t, 26t, and 29t sprockets when in the 34t chainring and pedaling backwards (forwards is no problem, but it's still kinda annoying).

I'm thinking i need a slightly longer chain to aleviate both problems which is something you'll want to consider if/when you get a new casette. (fortunately both my SRAM casette has only afew hundred miles on it while the chain has about 200% more miles so getting a new chain at this point really shouldn't cause any skipping/shifting issues due to mismatched wear). My only concern is to make sure i don't go with too long a chain that the rear derailuer can't fully tension the chain when in the small/small combo (though a bit of slack shouldn't be an issue since i'm usually already in the big ring by the time halfway through upshifting on the rear cassette...)
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Old 03-29-07, 03:42 PM   #6
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I think I'll go with the Century Special. It gives me a biit more flexibility. If I needed to climb trees, I could swap out the 30t and put in a 32t, whereas the Miche 10sp cassette is capped at 29t.
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Old 03-30-07, 12:34 PM   #7
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I can't see trading a 10-speed for a 9 just to gain 3 teeth on the big cog with somewhat questionable shifting, but it's your bike. If you go to a 32 you'll need a mountain type rear derailleur and probably more chain.
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Old 03-30-07, 01:19 PM   #8
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Quote:
Originally Posted by Al1943
I can't see trading a 10-speed for a 9 just to gain 3 teeth on the big cog with somewhat questionable shifting, but it's your bike. If you go to a 32 you'll need a mountain type rear derailleur and probably more chain.
What can I say? I'd rather have a gear that I don't need than need a gear that I don't have (and there have been plenty of times I wished I had a lower gear).
Besides, nothing is wasted - the old cassette and chain will be saved for later use. Hopefully, by the time the new cassette wears down, my knees will be in better condition, and I'll go back to the old 10sp setup.

Yes, I'll get a mtn RD if I end up putting a 32t cog on the cassette. Too bad Shimano 10sp cassettes can't be customized.
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Old 03-30-07, 02:13 PM   #9
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Quote:
Originally Posted by Psydotek
I have an SRAM 12-26 and recently pulled out the 14t cog and put in a miche 29t cog.
Where might I find a Miche 29t cog to fit on the back of my 12-26 SRAM? A quick search on the net isn't getting me far.

FYI for those interested, just recently switched from a Shimano compatable 12-26 SRAM to a 12-27 Ultegra cassette and the SRAM offers a crisper shift than the Shimano.
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Old 03-31-07, 07:35 AM   #10
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Quote:
Originally Posted by serpico7
Too bad Shimano 10sp cassettes can't be customized.
Are you sure?
I'll bet that you could add a 30 to the backside of your 10-speed 12-27 and remove the 16. The spacer between the 15 and 16 would go between the 27 and 30.
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Old 03-31-07, 07:44 AM   #11
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Quote:
Originally Posted by Al1943
Are you sure?
I'll bet that you could add a 30 to the backside of your 10-speed 12-27 and remove the 16. The spacer between the 15 and 16 would go between the 27 and 30.
I have heard that the last sprocket on a 10 speed cassette has a recess to allow it to fit on the hub. It may not be so easy to just put a loose cog at the end, but perhaps others have direct experience?
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Old 03-31-07, 01:55 PM   #12
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Quote:
Originally Posted by barba
I have heard that the last sprocket on a 10 speed cassette has a recess to allow it to fit on the hub. It may not be so easy to just put a loose cog at the end, but perhaps others have direct experience?
Correct. If it could be done, Sheldon Brown would be selling custom 10 speed cassettes.
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