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I am building a wheel with an Alfine 8 speed hub which has space for a disk brake. I am measuring the dishing by supporting the rim and measuring the distance from the table to the end of the through bolt of the hub, then flipping the wheel over, make the same measurement and then compare. They should be the same so that the hub is in the middle of the rim.

I am now on my third attempt after truing the wheel laterally and vertically I check the dishing and it is leaning towards the right (chain side) by over 1cm, cm not mm. By eyeing the wheel the hub does not look too out of center.

My question: is this method of measuring the dishing suitable for an Alfine hub with disc brake or should I expect some difference between the sides. Basically the difference is too great to be altered by adjusting the spokes.

Thanks for reading.

Gurnard
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  • That's the way you dish standard wheels. Note that most often the spokes on one side need to be a few mm longer than on the other side, to allow the proper dishing. And you should measure from the shoulder of the nut that bears against the inside of the dropout. There is an inexpensive "dishing tool" available to check this, or you can make one with a few pieces of wood and some bolts. – Daniel R Hicks Apr 06 '13 at 18:37
  • Hello. Thanks for the response. My spokes are the same length on both sides. This was taken from an online spoke caclulator. I don't fully understand the measurement that you mention, you talk about the shoulder of the nut that bears against the indside of the droput. All I have is a hub, flange of hub and central bolt (this is an internally geared hub). – Gurnard Apr 08 '13 at 07:57
  • Doing another, different, online caculation for spoke lengths it comes up as different lengths for left and right, although with the left spoke length longer than the right. But this would make my situation worse leaning the hub further over to the right where it is already too far on that side. – Gurnard Apr 08 '13 at 08:13
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    When you install the hub between the dropouts, there is a nut or bushing on the axle that fits against the inside of the dropout. That is the point you measure from, not from the end of the axle. – Daniel R Hicks Apr 08 '13 at 11:06
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    In this diagram, "O.L.D." is "over locknut dimension" (some diagrams/tables/calculators call it "OLN" for Over Lock Nut): http://sheldonbrown.com/images/nexus8-dimensions-h.jpg

    If you have dimensions B and C the same (as shown), then centring to the axle end will give the same answer, but as Daniel and jm2 say those locknuts are the bits that actually rest against the inside of your frame dropouts and determine exactly where the hub is.

     – armb Apr 08 '13 at 11:14
  • A photo of how you are supporting the rim and measuring might help decide why you aren't picking up the offset. But if you've changed to truing in the bike anyway, it doesn't really matter any more. – armb Apr 08 '13 at 11:21
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    Looking at that diagram, if you had equal length spokes done up the same amount, you would end up with the rim 2.7mm (dimension E) too far to the chain side. That's a Nexus 8, not an Alfine, but it's not going to be a lot different. – armb Apr 08 '13 at 11:33
  • armb, thank you very much for your advice I will give it all a go. Thanks for your help, much appreciated – Gurnard Apr 08 '13 at 15:42

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That sounds like it should work, although I would be measuring to the axle nut, not the axle itself, as the axle may not have exactly the same amount sticking out of both sides of the hub (likely not an issue).

If the rim is dished to the right then your driveside spokes are too tight and/or your non drive side spokes are too loose. Give everything about a half a turn- driveside loosened, non drive side tightened- and see where it gets you. Also, are you using a spoke tensiometer?

Let me offer an alternate method of getting your wheel trued up without a truing stand which might make things easier for you. Take your wheel (no tire) and drop it in your frame with the bike upside down, or put it in a workstand if you have one. Don't put the chain on. Attach a couple of zip ties to the chainstays or seatstays and cut them short, but not so short that they wont touch the rim. you can rotate the zip ties on the stays to get the closer to or further away from the rim to gauge how close to true you are and you can slide them up and down on the stays to see how close to round your are. That is basically the same way a professional truing stand works. When you are close on one side, flip the wheel around in the dropouts and repeat the process until you're happy with the results.

joelmdev
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  • thanks for the reply, I am using the upturned bicycle for vertical and lateral truing. Thanks. My spokes are the same length on both sides, provided by an online spoke calculator do you think this could be the issue? – Gurnard Apr 08 '13 at 07:54
  • Also, no, I am not using a spoke tensionmeter. Will this make a difference to the dishing? – Gurnard Apr 08 '13 at 08:14
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    Which spoke calculator are you using, and what hub dimensions? http://bike.shimano.com/publish/content/global_cycle/en/us/index/tech_support/tech_tips.download.-Par50lparsys-0015-downloadFile.html/08)%20Hub%20Dimensions.pdf gives centre-to-flange dimensions, but you might have to convert. The flanges aren't symmetrical, but I haven't checked whether they are enough out that the same size spoke won't manage, just nipples screwed further on to the short side. (I wouldn't expect a tensiometer to change whether you can get the dishing right.) – armb Apr 08 '13 at 11:04
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    See http://bicycles.stackexchange.com/questions/10701/how-effective-is-checking-spoke-tension-by-ear for checking tension without a tensiometer. – armb Apr 08 '13 at 11:05
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    Filling in some dimensions on a spoke calculator, the sides come out within 1mm of each other, so using the same size spoke should be fine. – armb Apr 08 '13 at 11:38
  • thanks armb you have cleared up some things for me. Yes the spokes are within 1mm so that should be good. I was not measuring the O.L.D, I was using the axle, so I will try that. Thanks for your fantastic replies with diagrams, very helpful. Will try with the correct measurements. – Gurnard Apr 08 '13 at 12:52
  • I've built an alfine11 into a wheel recently, and the spoke lengths were within 1mm so I just used the same length all round. It was the easiest wheel truing ever. – Criggie Dec 04 '18 at 00:52