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Old 08-16-09, 09:53 AM   #1
veloceleste
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Strumey X-RF8 speed/R20 chain rub

Hi,
Any suggestions are greatly appreciated. The chain rubs against the adjusment barrel in the fulcrum lever. When removing and re-installing the wheel I can set-up everything properly so that there is no rub. Once I start riding and shifting, (generally it happens with a multi-gear jump; ie 3 to 6) something causes the rub. I've tried adjusting the chain length, where the wheel sits in the dropout and the cable routing but nothing seems to prevent the rub . The one area I can't do myself and may be related is wheel dish, but I'm not sure if this has anything to do with it. Attached are several photos. Thanks again for any ideas. I hate a noisy bike not to mention the wear on the chain.




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Old 08-16-09, 10:30 AM   #2
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I would see if it is possible to bend the fulcrum lever outwards slightly. It looks like you don't need a great deal of clearance, so the change in cable angle wouldn't be significant.

Alternately, there is a different fulcrum lever (supposedly) available that comes out a different angle - but that would radically change your cable routing. It is either HSL910 (standard) or HSL938 (reversed).
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Old 08-16-09, 10:44 AM   #3
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Yah, mine did that too. I did both- bent the fulcrum lever a little bit and sacrificed some chainline by flipping the rear sprocket so that the teeth were closer to the axle. Also I used about 45 degrees of a brake noodle to make the turn out of the fulcrum. It doesn't touch at all now. I couldn't find the other fulcrum lever *anywhere*.
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Old 08-16-09, 11:40 AM   #4
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Originally Posted by Squeazel View Post
Yah, mine did that too. I did both- bent the fulcrum lever a little bit and sacrificed some chainline by flipping the rear sprocket so that the teeth were closer to the axle. Also I used about 45 degrees of a brake noodle to make the turn out of the fulcrum. It doesn't touch at all now. I couldn't find the other fulcrum lever *anywhere*.
Maybe post pix?

I had a similar problem with the Nexus7 on my "BMX folder". On that one I could play with antirotation washersbut still got the problem.

I ended up zip-tying the arm to the chainstay just after installing it to keep it in the position I wanted it to stay. I ment to use welcro instead to make a wheel change easyer. Forgot about it until reading this post. If you zip it make sure to bring extra strips with you in case of a flat.
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Old 08-16-09, 12:35 PM   #5
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I would try a different set of anti-rotation washers to get closer to the chain stay.

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Old 08-16-09, 02:36 PM   #6
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One fulcrum lever is designed for horizontal dropout slots (the fulcrum you have) and the other is designed for slots at 30 degrees (what you need).
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Old 08-16-09, 05:09 PM   #7
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Originally Posted by LWaB View Post
One fulcrum lever is designed for horizontal dropout slots (the fulcrum you have) and the other is designed for slots at 30 degrees (what you need).
+1

On my R20 the lever sits almost level with the chainstay.
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Old 08-17-09, 02:08 AM   #8
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I would try a different set of anti-rotation washers to get closer to the chain stay.

Aaron
Where do you buy them?


Quote:
Originally Posted by jur View Post
+1

On my R20 the lever sits almost level with the chainstay.
What is written on yours? They`ve got a code or a number on them. Can you read the one on yours? Best way to buy the right ones
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Old 08-17-09, 03:55 AM   #9
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Where do you buy them?
What country do you want to buy it from? Any decent supplier of SA parts will be able to source a different fulcrum arm.
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Old 08-17-09, 06:43 AM   #10
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Is it not true that most Sturmey archer sprockets are dished, and reversible to help with achieving a good chainline? It could be that the cog could be reversed / flipped so the teeth are a little nearer the hub, and a little bit away from the fulcrum arm. This might be all you need to do.
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Old 08-17-09, 06:54 AM   #11
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PS this is about the most comprehensive supplier of SA hub spares I know of (online)
http://www.sjscycles.co.uk/category-...Spares-426.htm
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Old 08-17-09, 09:01 AM   #12
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Thanks everyone for your suggestions. I bent the fulcrum lever out. Inelegant (that's me) but simple (that's me too) and effective. I also looked at S. Brown's 8 speed Twenty and upon close inspection of the picture it showed the fulcrum and cable adjustment assembly to the outside of the chain rather than above the chain.

What I still can't figure out is what changed from the time I first put everything together. The fulcrum was above the chain and there was no rub. Something must have shifted or wore down somewhere.

The other fulcrum lever (part # HSJ910) is for horizontal dropouts and HSJ911 is the fulcrum part # for angled dropouts.
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Old 08-17-09, 09:12 AM   #13
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Quote:
Originally Posted by LittlePixel View Post
Is it not true that most Sturmey archer sprockets are dished, and reversible to help with achieving a good chainline? It could be that the cog could be reversed / flipped so the teeth are a little nearer the hub, and a little bit away from the fulcrum arm. This might be all you need to do.
Depends...all my Twentys and the RSW Compact have flat sprockets, the fullsized bikes are all dished. Not sure about the newer stuff.

Aaron
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Old 08-18-09, 12:25 AM   #14
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Originally Posted by LWaB View Post
What country do you want to buy it from? Any decent supplier of SA parts will be able to source a different fulcrum arm.
I buy most of my stuff from UK, SJS and Wiggle. Did not see the big IGH secton before now. Guess I looed under "drivetrain" before.
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