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-   -   Sturmey Archer hub and chainline adjustment (http://www.bikeforums.net/folding-bikes/686433-sturmey-archer-hub-chainline-adjustment.html)

chagzuki 10-08-10 05:29 PM

Sturmey Archer hub and chainline adjustment
 
I think my chainline is out by slightly too much of a margin, my chainring is wearing on one side much faster than the other and on examination the chain tends to pull to one side of the ring. . . I can't remember exactly how I calculated the chainline, I swapped the original chainset out around 2 years back and haven't messed with it since. I don't have the option of moving the ring closer towards the frame as there isn't space, it'll touch. The Sturmey Hub is one area of my bike that I've not delved into beyond setting the gears correctly, is there an easy way to move the cog for chainline adjustment?

Dynocoaster 10-08-10 06:00 PM

Get a shorter BB.

BruceMetras 10-08-10 07:49 PM

Is the cog dished to the outside? If not, then you could flip it.. If yes, then you get to play with getting the cog closer to the chainstay with manipulation of nuts and washers.. and of course, re-centering the rear wheel..

chagzuki 10-09-10 03:45 AM

That initial post was written by my idiot identical twin who, in a state of tiredness somehow had reached the entirely wrong conclusion; in fact the chainring needs to move away from the frame so a longer BB would do. Switching from 113 to 118 spindle. . . hang on. . . the 118s are for triple chainsets aren't they? Does that mean that the right-hand side of the spindle is longer than the left? I'm wondering if that amounts to a 2.5 mm increase on both sides or if it's more on the drive side.

chagzuki 10-09-10 04:02 AM

Does the hollowtech 2 crank/bb system get rid of these problems? I read something about it enabling chainline adjustment.

wahoonc 10-09-10 05:59 AM

Normally a triple BB axle will add more length to the chain ring side. Depending on the SA hub you can flip the dished sprocket and there are some spacers that can be moved around the cog also. Caveat; I do this with my hubs but all my Sturmey Archers hubs are pre 1980.

Aaron :)

chagzuki 10-09-10 06:18 AM

I've not disassembled the freewheel section, I'm not familiar with the mechanics of it. It looks as though I need a specific spanner. . . and whilst cleaning my cog I've realised there's some grit between dustcap and hub. . . I don't know if I can flush it out with oil? If not I guess I'll have to remove the dust cap and clean inside.

chagzuki 10-09-10 06:39 AM

It's an X-RF5 hub btw. I'm having trouble discerning how the freewheel/sprocket works from the instructions.
My terminology is probably off, but it looks to me as though there's an additional locknut on top of the one in the instructions. I can't see any spacers or space for spacers.

chagzuki 10-09-10 06:48 AM

From what I can see there's a locknut on the outside that's 34.7mm with a triple indentation, and inside that there's another that's 36.8mm with a single indentation.

Edit: is lockring the correct term. . . hang on, the instructions have the inner ring with single indentation as a "circlip".

chagzuki 10-09-10 06:55 AM

Ah, there aren't 2 rings, the outer region is part of the freewheel and the circlip is what holds the sprocket in place? According to this:

"Place the wheel on its side with the sprocket facing upward. Take a careful look at the mechanism and locate the spring circlip. This is the snap ring that holds the sprocket in place on the hub.
3

Fit the flat-head screwdriver into the circlip's groove. Use leverage to pry up the ring a bit at a time, gradually moving around the outside groove. Set the circlip aside."


That sounds like a really messy way of doing things, I'm worried that I'll scrape/dent the parts. Has this been designed by someone who's attracted to risk / danger? An extreme sports fanatic perhaps?

SesameCrunch 10-09-10 07:55 AM

Quote:

Originally Posted by wahoonc (Post 11596188)
Depending on the SA hub you can flip the dished sprocket and there are some spacers that can be moved around the cog also.

Aaron :)


Quote:

Originally Posted by BruceMetras (Post 11594754)
Is the cog dished to the outside? If not, then you could flip it.. If yes, then you get to play with getting the cog closer to the chainstay with manipulation of nuts and washers.. and of course, re-centering the rear wheel..

+1. I would try this suggestion first. It's the most obvious answer and easy to remedy.

If you have questions, take a picture of the hub from the back and we can spot it for you.

chagzuki 10-09-10 09:17 AM

I've fought my way past the circlip system. . . much to my relief. For a while there I thought I wasn't going to get it back on.

I'm using a 13T sprocket so it doesn't seem as though I could get a dished one. I think I'm limited to changing the BB.

chucky 10-09-10 09:50 AM

Quote:

Originally Posted by chagzuki (Post 11596620)
I've fought my way past the circlip system. . . much to my relief. For a while there I thought I wasn't going to get it back on.

I'm using a 13T sprocket so it doesn't seem as though I could get a dished one. I think I'm limited to changing the BB.

Why can't you add chainring spacers to move the chainring further to the right of the spider?

chagzuki 10-09-10 12:46 PM

I've got double 105 cranks with ring on inside and chainguard on outside.

chagzuki 10-10-10 05:26 AM

As if by magic I found a 118 octalink BB in my spares box, which is now installed and ready to go. The chain looks to want to sit more centrally over the chainring. . . will see later today if all feels slightly smoother.

I must have based my chainline on what I gathered from the sheldon brown website where he appears to measure a triple chainset from the inner side of the middle ring. Is that correct, that it's the inner side of the ring and sprocket that are used in measurement (in official stats)?

With the wheel built I can't easily measure the hub sprocket position myself so I'm going by the Sturmey Archer site.


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