SRAM derailleur pulleys
03-14-19, 07:05 PM
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SRAM derailleur pulleys
Side to side play indicates the pulleys need to be replaced? I took the X7 derailleur off my 2007 Dahon folder awhile ago; now I may need to put it back on. SRAM uses what looks, from the parts manual, like a nearly infinite variety of pulleys. But I suppose I can get the right ones if I need to. The upper one here is weird. The post doesn't go through the center of the pulley; it's offset. I don't know why SRAM would do that except to make sure I have to go to them for replacements. Anyway there shouldn't be much movement side to side, right?
03-15-19, 12:37 AM
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The upper pulley has some play side-to-side to help with indexing. Unless it’s rocking, it’s fine.
03-15-19, 06:13 AM
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Or do you mean that the center of the pulley is not mounted on the center of the cage pivot, and that is offset some (like many derailleurs are, especially Shimano and clones)? I think this is often done to keep pulley spacing with the cassette more consistent.
03-15-19, 06:58 AM
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Here's the view from SRAM's parts book. My lower pulley is different, but the upper is identical. The drawing doesn't show the fixing bolt for the upper pulley but what's different is it doesn't go through the center. You can see from the dash rule that indicates alignment, it goes through one of those outer holes. A nub on the cage engages the other hole on the cap to ensure that just the pulley, not the hub or caps, does the spinning. Weird, right? Anyway there's 1-mm side to side play or just slightly more between the pulley and the cage, which seems to me like a lot in such a small item.
Why I took the derailleur off in the first place: It seemed like there was a lot of resistance to the chain moving through it, especially noticeable when back pedaling. I put on an Altus and there was a world of difference. Now I might need the Altus for another bike. I wish there was someone to ask at SRAM.
Why I took the derailleur off in the first place: It seemed like there was a lot of resistance to the chain moving through it, especially noticeable when back pedaling. I put on an Altus and there was a world of difference. Now I might need the Altus for another bike. I wish there was someone to ask at SRAM.
03-15-19, 07:25 AM
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