Bicycle Mechanics - Change rear hub, use existing spokes

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mikehattan
08-25-11, 10:55 AM
Hi, I have a Shimano Ultegra FH-6700 rear free hub (36 hole) on a set of wheels I built up this winter. I would like to swap out that hub for a cheaper one (and use the Ultegra hub in a newer build up).

My question: what is the easiest/best way to find a new (or used) hub with the same flange dimensions so that I can rebuild the wheel without having to buy new spokes?

Any decent rear hub that will accept a 9-sp cassette will be fine. The wheels will be used on a commuter.

Thanks in advance.

fietsbob
08-25-11, 11:13 AM
.. if the flange/spoke hole diameter and the spoke hole count is identical.

look at the lower cost Shimano hubs .. the ones supplied on $400 bikes, now, seem pretty good,
they added Rubber seals that you pry off to adjust the cones.
gyozadude
08-25-11, 04:37 PM
If you check Sheldon Brown's site, he has a link to a spreadsheet, spocalc.xls that has 3 tables, one of them for hubs. There should be a reference to some 600 Ultegra Hubs, maybe from previous generations. But you'll see that most modern Shimano freehubs have 45mm diam. separation on holes, and 37 - 38 left flange spacing from center, and 20 - 24mm right flange spacing from center. And if you get the same number of holes, you may notice that even starting from Acera and Altus, and even with the MTB hubs, the flange size and spacings are really similar to each other. So if you selected spokes that aren't too long or too short for your original build, then it's very likely, those lower end hubs are likely to work fine.

mrrabbit
08-25-11, 06:30 PM
http://www.mrrabbit.net/wheelsbyflemingapplications.php

Grab the spreadsheet.

Use the "spokechart" tab to view the hubs.

=8-)
mikehattan
08-25-11, 08:02 PM
Use the "spokechart" tab to view the hubs.


Thanks, is the "offset" center to flange?

What is a reasonable range in offset to consider? +/-1 mm?
mrrabbit
08-25-11, 11:14 PM
Yes...the center of hub to center of flange is "offset".

1mm of offset change typically amounts to maybe a .25mm change in spoke length. Changes in ERD are something to be much more concerned about.

=8-)
Jeff Wills
08-25-11, 11:32 PM
Yes...the center of hub to center of flange is "offset".

1mm of offset change typically amounts to maybe a .25mm change in spoke length. Changes in ERD are something to be much more concerned about.

=8-)

And 0.25mm is insignificant. Spokes have at least 2mm wiggle-room in terms of length.

OP: any small-flange Shimano hub will be so close to your Ultegra hub that there's no practical difference.