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My 26" singlespeed conversion -- with pics

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Singlespeed & Fixed Gear "I still feel that variable gears are only for people over forty-five. Isn't it better to triumph by the strength of your muscles than by the artifice of a derailer? We are getting soft...As for me, give me a fixed gear!"-- Henri Desgrange (31 January 1865 - 16 August 1940)

My 26" singlespeed conversion -- with pics

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Old 03-04-07 | 10:47 PM
  #26  
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Originally Posted by CdCf
Damn...

I forgot about the bulging chainstay... I knew there was a reason for having to get a 127 mm spindle.
What good will a 127 mm spindle do, to avoid rubbing against the chainstay vs. chainline? Your problem was that the chainline was incorrect when the chainring was on the outside of the spider. A wider spindle will copound the chainline problem even more.

So, what's the solution? Why, a smaller chainring, or re-dish the rear wheel to push the sprocket (more commonly, but incorrectly, called "cog") more to the right. If you re-dish, you'll have to re-spacer the axle, as well. I don't know how one can do that if it's a QR skewer axle.
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Old 03-05-07 | 12:52 AM
  #27  
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Originally Posted by wroomwroomoops
What good will a 127 mm spindle do, to avoid rubbing against the chainstay vs. chainline? Your problem was that the chainline was incorrect when the chainring was on the outside of the spider. A wider spindle will copound the chainline problem even more.
No, I now have a 127 mm spindle, which was the shortest that would allow the ring to clear the chainstay.

Originally Posted by wroomwroomoops
So, what's the solution? Why, a smaller chainring, or re-dish the rear wheel to push the sprocket (more commonly, but incorrectly, called "cog") more to the right. If you re-dish, you'll have to re-spacer the axle, as well. I don't know how one can do that if it's a QR skewer axle.
Redishing the rear wheel? That would accomplish nothing but making rear braking impossible.
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Old 03-05-07 | 01:58 AM
  #28  
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Originally Posted by CdCf
No, I now have a 127 mm spindle, which was the shortest that would allow the ring to clear the chainstay.
I understand that, but putting the chainring further away from the bike's middlepoint would increase your chainline problems.

[QUOTE=CdCf
Redishing the rear wheel? That would accomplish nothing but making rear braking impossible.[/QUOTE]

No; redishing is necessary EXACTLY for the reason to keep the rim in the centerline, while pushing the hub sideways. That's why I also mentioned that you have tofiddle with the axle spacers, too.


Anyway, do as you wish, but trust me on this: chainline is critical.
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Old 03-05-07 | 05:32 AM
  #29  
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Originally Posted by wroomwroomoops
I understand that, but putting the chainring further away from the bike's middlepoint would increase your chainline problems.



No; redishing is necessary EXACTLY for the reason to keep the rim in the centerline, while pushing the hub sideways. That's why I also mentioned that you have tofiddle with the axle spacers, too.


Anyway, do as you wish, but trust me on this: chainline is critical.
You don't seem to understand what my problem is...

First, I never said I'd move the chainring AWAY from the centreline. It's as far in as it can go already.

1. I can't move the chainring farther in towards the frame. It will then hit the chainstay.
2. I can't move the sprocket farther out towards the fork end. It will run out of freehub splines to engage.

The hub fits precisely into the rear fork end's width - adding a 3 mm spacer on the non-drive side would force the frame to open more than it "should". I'm not sure that's a good thing to do to an alu frame.
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Old 03-05-07 | 06:36 AM
  #30  
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Originally Posted by CdCf
You don't seem to understand what my problem is...

First, I never said I'd move the chainring AWAY from the centreline. It's as far in as it can go already.

1. I can't move the chainring farther in towards the frame. It will then hit the chainstay.
2. I can't move the sprocket farther out towards the fork end. It will run out of freehub splines to engage.

The hub fits precisely into the rear fork end's width - adding a 3 mm spacer on the non-drive side would force the frame to open more than it "should". I'm not sure that's a good thing to do to an alu frame.
Oh, I understand perfectly your problem, and that's why I said that you should

1. Get a smaller chainring.
2. Redish the rear wheel - provided that you are able to move/change the spacers on the right and the left side of the axle. If you can't (and apparently you can't), then redishing won't work for you.

So the only option left for you is to get a smaller chainring. Which I mentioned a few posts ago.

EDIT: And now, seriously, do as you wish. I know what I'm talking about - after all, I have solved chainline problems with all the bikes I've built, but don't substitute your opinion for mine, and just go ahead and do whatever you think is the smartest thing to do. I am really NOT interested to hear about this issue anymore, and neither am interested to explain myself further.

Last edited by wroomwroomoops; 03-05-07 at 06:51 AM.
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Old 03-05-07 | 07:24 AM
  #31  
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1. I'm not interested in getting a smaller chainring, since I wanted as high a gearing as possible.
2. There are no spacers on the hub (at least not on the drive side), so I presume you're suggesting I add them. That would make the total hub width greater than the fork ends were designed for, and that doesn't sound like a sensible solution to me.

But forget it. I just thought earlier that I had found a solution, but later commented that I hadn't. I never intended to start an argument. Sorry.
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