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Old 12-04-11, 04:50 PM   #1
uprightbent
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Fit a 135 hub into 126 rear spacing Without Cold Setting?

I'm contemplating an Alfine 8 in the rear of a mid-80's touring frame with 126mm rear spacing. Although I'm not opposed to getting a pro to properly cold set the frame, I'm wondering as some have suggested that I might be able to spring the triangle to get it in, or is 9mm just too much to force? And if I do get it in, I guess the problem comes back when replacing a flat on the road. In the dark. And rain of course.

Thanks for any advice!
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Old 12-04-11, 05:52 PM   #2
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What about a red-band Nexus 8 instead (SG-8R36). They are 132mm wide. You could theoretically cut the nut (nut holds the dust cap on) on the non-drive side in half and get it down very close to 129mm. Cold setting 126 to 130 should be easily doable. The nut would have to be cut in half with some precision, to maintain the parallel sides (ideally cut in a lathe for example).

I'm planning on installing a Nexus 7 on a 126mm spaced bike. The Nexus 7 is 130mm wide, I'm going to cut the non-drive side nut to get it really close to 126mm

Of course, the Nexus 8 is only available in painted grey. So if aesthetics are concerned, you might have to stick with an Alfine. Supposedly the SG-8R36 has the same internals, but I don't know for sure.

I believe that supporting the brake bridge and the bridge between the chainstays might be in order for a cold setting of that magnitude (126 to 135).

Edit: Support as in some sort of external clamp to reduce any stresses on the brake bridge.

Last edited by krome; 12-04-11 at 06:34 PM.
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Old 12-04-11, 06:10 PM   #3
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If you manage to somehow spread the stays to another 9 mm of spacing between the dropouts, the dropouts will be so out of square that you'll likely break the hub. The axle locknuts will tend to follow the angle of the droputs, causing bending stress on the axle and bearing misalignment.

Consult someone with proper tools and knowledge.
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Old 12-04-11, 06:16 PM   #4
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An additional problem with extensive "springing" of the frame is that the dropouts will no longer be parallel. This will make it more difficult for the axle nuts to clamp it securely and will also exert a bending moment on the axle which will add unwanted stress which could make it more susceptible to breakage. Proper cold setting of the frame will include realignment of the dropouts back to parallelism.
Edit: oldbobcat beat me to the punch, so to speak.
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Old 12-04-11, 06:46 PM   #5
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That's the biggest problem with excessive spread...knocks dropouts out of parallel - which leads to bent and broken axles.

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Old 12-04-11, 06:59 PM   #6
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I believe all the above points are moot anyway, you'd have to be pretty strong to bend a frame enough to fit a 135mm hub. 126-130 is easy, but I tried 126-135 once and couldn't do it. I'm a weakling though, maybe others would have better luck.

Since this is an IGH rear just find the correct hub to fit (130mm is fine) or get the frame properly cold set.
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Old 12-05-11, 10:23 AM   #7
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I've run a 135 wheel in a 126 frame once with squeezing it in. It was a chore, and I will not do it again.
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Old 12-05-11, 10:29 AM   #8
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... Perhaps there are some spacers, that can be removed under the lock nuts,
or substitute thinner ones.. to reduce the over all width of the axle.

And Shimano supplies hubs to companies that make folding bikes ,
so there are narrower versions of the hub for that market.

Last edited by fietsbob; 12-05-11 at 11:46 AM.
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Old 12-05-11, 10:36 AM   #9
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I cold set a Schwinn Cutter hi ten single speed frame from 110 to 120. No big deal. I simply used a large (8"?) C-clamp. I put the fixed end of the clamp inside one dropout, and the rotating part inside the other. It fit well enough and didn't slip. Then I just unscrewed the clamp until it was set were I want. A lot easier that I would have guessed; took less than 5 minutes.
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Old 12-05-11, 11:15 AM   #10
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I have cold set a steel frame from 126mm to 132mm for a Nexus 8 Red band. I used Sheldon Brown's 2x4 method. Be sure to bend the dropouts to be parallel again. This was before I realized that the nut on the non-drive side is basically a threaded spacer that holds the dust cap on. You could remove it entirely, but that would make things more complicated as the metal portion of the dust cap could fall out during a wheel removal.

Link to Sheldon's frame spacing:

Frame spacing
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Old 12-05-11, 12:31 PM   #11
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I've done it before, and spreading the stays is a real pain. Don't worry about dropout alignment, my quick math indicates the difference in dropout angle is less than 2 degrees. I'd bet most frames are out of alignment that much on their own; who knows, you could actually be fixing it. Instead, worry about what happens if you get a flat and need two people to spread the chainstays.
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Old 12-05-11, 12:51 PM   #12
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So Sheldon says you should have someone professionally align the dropouts. How crucial is that? There's no way to do it yourself?
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Old 12-05-11, 01:18 PM   #13
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Quote:
Originally Posted by oldbobcat View Post
If you manage to somehow spread the stays to another 9 mm of spacing between the dropouts, the dropouts will be so out of square that you'll likely break the hub. The axle locknuts will tend to follow the angle of the droputs, causing bending stress on the axle and bearing misalignment.

Consult someone with proper tools and knowledge.
The old cat knows whereof he speaks. Too much bending stress on the axle that will screw up the bearings.
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Old 12-05-11, 01:53 PM   #14
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Originally Posted by himespau View Post
So Sheldon says you should have someone professionally align the dropouts. How crucial is that? There's no way to do it yourself?
A couple pieces of threaded rod and some nuts and washers. Put the threaded rods in the dropouts and tighten them down so the ends are nearly touching each other in the middle between the dropouts. Take a big crescent wrench and bend the dropouts until they're parallel as indicated by the threaded rods. Do it slowly in many small steps, alternating sides.

There's a tool to do it that works about the same way, but the threaded rods are cheaper.
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