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Old 05-17-07, 11:55 PM   #1
Scorer75
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Simple cassette question

I currently have an SRAM PG970 12-26 on my bike. It's a 9 speed in case that matters.

I want to have a second cassette to swap out instead of having to clean the one on the bike. The idea here being I would always have one clean and ready to go.

Could I swap an SRAM PG970 11-23 without making any other changes to the bike?

Could I go with an Ultegra 9 speed cassette, again, without making any modifications?

Could I go with an 11-34 cassette?
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Old 05-18-07, 01:09 AM   #2
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IF your bike came with the 12-26, your Rder probably can't handle the 34. So you would probably need to go to a long cage RDER and a longer chain. The longer chain would probably be a little "sloppy" on the smaller cassettes.
The other combos should be no problem.
You might post what size chain rings & DER brands/Part numbers you currently have for a more definitive answer.
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Old 05-18-07, 04:08 AM   #3
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Quote:
Originally Posted by Bill Kapaun
IF your bike came with the 12-26, your Rder probably can't handle the 34. So you would probably need to go to a long cage RDER and a longer chain. The longer chain would probably be a little "sloppy" on the smaller cassettes.
The other combos should be no problem.
You might post what size chain rings & DER brands/Part numbers you currently have for a more definitive answer.
Close, but not exactly right.

With a cassette that has a 34 big cog you will need a MOUNTAIN BIKE rear derailleur. A long arm road bike derailleur still won't handle the biggest rear cogs. You should also install a new longer chain to safely cover the big/big combination because accidentally shifting into the big/big with a too short chain can cause a LOT of damage to your bike.

The longer chain, as long as your rear derailleur has adequate slack take up, will have no ill effects on the smaller cogs.
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Old 05-18-07, 07:13 AM   #4
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Ok, I realized the 11-34 was a mountain cassette after I posted the question.

What about going from my current 12-26 to an 11-23?

I've got a rear Ultegra derailer and a compact 48/36 crank.
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Old 05-18-07, 08:51 AM   #5
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The 11-23 would probably work. A thing to remember is that no cassette will sit exactly where the old cassette did and you may have to make minor adjustments to your der to accomodate.
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Old 05-18-07, 08:54 AM   #6
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Do you want to change your gearing or are you too lazy to clean the cassette? I'm confused.

I find it's easier to clean a cassette on the bike with a rag then to pull everything apart.
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Old 05-18-07, 09:02 AM   #7
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Originally Posted by Cynikal
Do you want to change your gearing or are you too lazy to clean the cassette? I'm confused.

I find it's easier to clean a cassette on the bike with a rag then to pull everything apart.
what difference does it make?

it'll work.

ed rader
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Old 05-18-07, 09:42 AM   #8
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Quote:
Originally Posted by Scorer75
Ok, I realized the 11-34 was a mountain cassette after I posted the question.

What about going from my current 12-26 to an 11-23?

I've got a rear Ultegra derailer and a compact 48/36 crank.
No problem. You probably won't have to change or adjust anything. If you do it, I'd advise swapping cassettes frequently so that they'll wear evenly. Otherwise you might find that the chain skips over a favorite cog in one or the other cassette.
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Old 05-18-07, 09:46 AM   #9
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Quote:
Originally Posted by erader
what difference does it make?

it'll work.

ed rader
Ultimately it will be more work for the OP to swap cassettes and re-adjust than to just clean. But hey, not my bike.
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Old 05-18-07, 11:12 AM   #10
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Thanks for the input.

The initial purpose of doing this was so that I don't have to clean the cassette while on the bike. I always keep my drivetrain really clean and I find it a pain to clean the cassette properly.

I admit it, I'm lazy. When I grease my chain (White Lightning) I pour it on while spining the cranks. This gets some of the waxy substance on the cassette which turns into a greasy mooshy dirt on the surface of the cassette when it gets dirty.

So, I thought it would be nice to be able to remove the cassette, drop it in water mixed with dishwashing soap, and leave it for a day or two. Then I could rinse and wipe it down, put it back together, and always have a clean cassette to swap in for the dirty one.

Then I figured that if I was already getting a new cassette, it might be nice to have one with just slightly different gearing.

2 things:

1. Good point about alternating frequently to keep the wear factors of both cassettes and the chain consistent.

2. Why would I need to adjust the der. if they are both 9 speed PG970's?
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Old 05-18-07, 11:21 AM   #11
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Quote:
Originally Posted by Scorer75
Why would I need to adjust the der. if they are both 9 speed PG970's?
B screw adjustment would probably need to be changed with different sized largest cogs. The B screw adjustment determines the size of the gap between the upper pulley and the largest cog when the derailleur is in the large cog position-
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Old 05-18-07, 11:35 AM   #12
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Originally Posted by well biked
B screw adjustment would probably need to be changed with different sized largest cogs. The B screw adjustment determines the size of the gap between the upper pulley and the largest cog when the derailleur is in the large cog position-
Even if I'm currently running a 12-26 and going to an 11-23?

What if I went with another 12-26, would I still need to make adjustments?
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Old 05-18-07, 11:46 AM   #13
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In the case of the 12-26 to 11-23, you'd just have to try it and see what kind of performance you get. The idea is to not let the cog and pulley interfere with each other of course, but to have only a small gap for best shifting performance. Obviously by changing the size of the largest cog, you're changing the size of the gap. Going between two identical nine-speed cassettes (12-26 to 12-26) would mean no adjustments necessary-
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Old 05-18-07, 11:54 AM   #14
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Thanks for the input.
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Old 05-18-07, 11:59 AM   #15
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Odd reason for swapping cassettes....having a clean one on hand, and a different cassette....

Last edited by roadfix; 05-18-07 at 12:39 PM.
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Old 05-18-07, 12:02 PM   #16
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The neck of an old t-shirt or the waistband of an old pair of briefs works really well for cleaning a cassette.
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Old 05-18-07, 12:19 PM   #17
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I've switched 9-speed cassettes many many times without adjusting anything, but all of these cassettes were Shimano. Usually if an adjustment is needed it will be due to some minor difference in the lateral position of the cogs. This can happen if there is a difference in the built-in spacer thickness on the first position cog or if for any other reason there is a slight difference in positions between brands.
Any cassette with an 11t first position will require a special lockring, it should come with the cassette.
I've run everything from a 12-23 to a 13-28 with no adjustments of any kind.
As for cleaning, I soak a rag in mineral spirits, fold it so that it fits tightly between the cogs, and floss the cogs by turning the cassette backwards. I do this 2 or 3 times per month and have no reason to remove the cassette just for cleaning.

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