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Old 05-15-09, 04:42 PM   #1
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Shifter compatibility

If I replace an 8 speed 11-28 cassette with a 11-32 or 11-34 cassette will my Shimano STX RC 8-speed trigger shifters still work okay? I am using a long cage Sram rear mech. Any advice would be appreciated.
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Old 05-15-09, 05:09 PM   #2
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The shifters themselves will still work fine when changing to a different 8-speed cassette. However, since you've added 4 teeth (or 6 for the 11-34) to your previous maximum rear gear size, you should be using an appropriately longer chain (in practice, this might wait until your next chain replacement) and you will likely have to adjust the rear-derailleur's B screw. Since you mention a long-cage rear derailleur (I assume SGS equivalent), your rear derailleur probably has enough "capacity" to handle the extra length of chain once you make that change.

If you post the specific model number of your rear derailleur, we might be able to look up the specs and verify the capacity.
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Old 05-15-09, 07:14 PM   #3
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Originally Posted by s1h2a3y4n5a6 View Post
If I replace an 8 speed 11-28 cassette with a 11-32 or 11-34 cassette will my Shimano STX RC 8-speed trigger shifters still work okay? I am using a long cage Sram rear mech. Any advice would be appreciated.
Tony
If it works now, all that you'll need is a couple extra links in the chain to go around the larger cog. As your bike sits now, the chain will probably jam if you try to shift it into the largest cog.

I'm a little mystified, though. In theory, a SRAM rear derailleur shouldn't work with a Shimano shifter- they use different amounts of cable travel. What kind of SRAM derailleur is it?
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Old 05-15-09, 09:09 PM   #4
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I'm a little mystified, though. In theory, a SRAM rear derailleur shouldn't work with a Shimano shifter- they use different amounts of cable travel. What kind of SRAM derailleur is it?
I had the same thought, but it sounds like the OP has mountain type shifters and derailleurs. I think maybe in that case you can mix Shimano and SRAM. I don't know but I'd like to hear from some of the SRAM experts here. It's my understanding that SRAM road derailleurs are not compatible with Shimano shifters.
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Old 05-15-09, 10:48 PM   #5
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I had the same thought, but it sounds like the OP has mountain type shifters and derailleurs. I think maybe in that case you can mix Shimano and SRAM. I don't know but I'd like to hear from some of the SRAM experts here. It's my understanding that SRAM road derailleurs are not compatible with Shimano shifters.
Nope... SRAM derailleurs use a 1:1 ratio of cable pull to derailleur movement. Shimano uses 2:1 universally- mountain and road.
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Old 05-16-09, 04:10 AM   #6
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Shifter advice

Thanks - I intend to fit a new chain, so I will adjust the length accordingly, as I am replacing 22-32-42 chainset with 26-38-48 triple and not using the large 48 ring. The old 11-28 cassette and 22-32-42 chainrings are all badly worn, hence the need for replacement - I just happen to have an old (unused) 26-38-48 Sugino crankset. I have yet to get a cassette but I think I will go for a Shimano HG50 11-34, and see how I get on. I am unable to find a serial number or any identification on the Sram derailleur, so maybe I'll have to replace that too! It seemed to work fine with the old set-up, notwithstanding damaged teeth etc.
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Old 05-16-09, 04:21 AM   #7
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Jeff - SRAM makes two types of rear derailleurs: one type uses the Shimano shift ratio and one type uses SRAM's smaller ratio. This is for their mountain stuff - I don't know about their road stuff. From what I've seen, the high-end mountain stuff is all SRAM ratio, but some of their low- to mid- level stuff is Shimano ratio.

Here's one of the SRAM RD's w/Shimano ratio: http://www.universalcycles.com/shopp...4&category=692

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Old 05-16-09, 04:28 AM   #8
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s1 - any chance of posting a photo of your rear derailleur? Also, does it feel loose or jiggle/rattle when you pull on it?
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Old 05-16-09, 06:06 AM   #9
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shifter compatibility

Thanks Jeff/Mondoman - the Sram rear mech is an early/mid 90's model - no apparent identification. How do I post a photograph?
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Old 05-16-09, 08:45 AM   #10
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... How do I post a photograph?
When you reply to a message, look for the Manage Attachment button below message editing area. You need to select the file using Browse and submit using Upload.

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Old 05-16-09, 08:50 AM   #11
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Nope... SRAM derailleurs use a 1:1 ratio of cable pull to derailleur movement. Shimano uses 2:1 universally- mountain and road.
Which one pulls the cable more per click SRAM or Shimano?

Thanks,

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Old 05-16-09, 08:22 PM   #12
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Which one pulls the cable more per click SRAM or Shimano?
SRAM.

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Old 05-16-09, 08:24 PM   #13
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Here's one of the SRAM RD's w/Shimano ratio: http://www.universalcycles.com/shopp...4&category=692
Ah, so... I wasn't aware they still made Shimano-compatible derailleurs. Next thing you know, Shimano will be making SRAM-compatible shifters!
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