CYCLINGFORUM.COM - Where Cyclists Talk Tech --- Return To Home

 

    Register FAQ'sSearchProfileLog In / Log Out

 

****

cyclingforum.com ****

HOMECLUBS | SPONSORS | FEATURESPHOTO GALLERYTTF DONORS | SHOP FOR GEAR

Return to CyclingForum Home Page CYCLING TECH TALK FORUM
          View posts since last visit

Wheel build question- odd hub set up
 

Author Thread Post new topic Reply to topic
Brian Kelly
Joined: 12 Jan 2004
Posts: 653
Location: Gig Harbor, WA

3/28/13 12:11 PM

Wheel build question- odd hub set up

One of the spokes on my rear wheel recently pulled through the hub flange. The rim was still in good shape, so I decided to try and rebuild the wheel. I picked up a used hub, and noticed the spoke holes weren't staggered from one flange to the other. In other words, if I was looking through a spoke hole, I could see directly through the spoke hole on the opposite flange. It appears the the hub was originally designed for some sort of paired spoke pattern, and so the spoke holes on the hub would line up with each other.

My question is, do you think the hub can be built up in a more normal crossing pattern? For reference, it is a 24 hole rim and I was planning on building it up 2x both sides. New spokes as the old bladed one won't fit through the spoke holes of the new hub.

If I do try, do you think I would need to make any adjustments to spoke length calculations? I'm thinking no, that difference would be small enough that it wouldn't effect normal spoke figures but please correct me if I'm wrong.

THANKS[/i]

 Reply to topic     Send e-mail

Nick Payne
Joined: 10 Jan 2004
Posts: 2455
Location: Canberra, Australia

3/28/13 4:09 PM

I would think that not having the spoke holes offset would make it difficult to build a wheel with normal crossed spokes. On a normal rear hub with 32 holes and 45mm flange diameter, the spoke holes are about 4-1/2mm apart. If you're building a wheel 3x and have the spokes on one side threaded to a consistent depth in the nipples, the alternate spokes on the other side that go in different directions are going to need to be either about 2mm longer or shorter than nominal. A total difference of 4mm is rather more than you should be trying to accommodate with a single spoke length on the one side - the spokes going one way will tend to bottom out the thread on the spokes, meaning they can't be brought to tension, and the spokes going the other way won't have the thread full depth in the nipple, meaning that the head of the nipple isn't properly supported by the spoke threads and and can actually break off somewhere down the line.

If you try to balance the plus/minus of the spokes between the two sides, it's going to take a lot longer to build the wheel than normally, and you still might possibly run into the problems I've outlined above.

 Reply to topic    

Sparky
Joined: 08 Dec 2003
Posts: 17552
Location: Portland, OR

3/28/13 4:17 PM

google:

http://www.bikeforums.net/archive/index.php/t-726035.html

And this guy wrote a program for the task:

http://thefsb.wordpress.com/2011/04/11/289/

Same hole placement on both flanges is not addressed. I see that as a problem as well/

 Reply to topic     Send e-mail

Brian Kelly
Joined: 12 Jan 2004
Posts: 653
Location: Gig Harbor, WA

3/30/13 4:20 PM

thanks for the feedback so far. Just to be clear, the spoke holes are drilled in a normal, non-paired, manner.






The spoke holes are all equidistant from one another like on a "regular" hub, but the spoke holes for each flange line up as opposed to being offset. If you look at the spoke hole in roughly the 12:00 position, you can see directly through the spoke holes on each side of the flange.

The spokes end up being directly paired with on another:



I think Nick is probably right though. I'm not sure I want to go through the trouble of sorting out the different lengths that would be needed to make the hub work.

 Reply to topic     Send e-mail

daddy-o
Joined: 12 Apr 2004
Posts: 3304
Location: Springfield

3/30/13 9:49 PM

In the photo the spokes deformed the flange as expected. Since this looks like the non-drive side, it doesn't look like it was a half-radial lace-up before like I thought it could have been.

How do the drive and non-drive side wear patterns line up? Are the drive side pulling spokes on the inside face too? Are they staggered like a normal hub?

If you're willing to take the time you can mock up the cross pattern with a few spokes and some tape. That would work on one side. It would be even easier to test your paired spoke setup because you could do that with two spokes.

I'm not trying to yank your chain but, is the photo yours? The date stamp, that's all.

Good luck.

 Reply to topic     Send e-mail


Return to CyclingForum Home Page CYCLING TECH TALK FORUM
           View New Threads Since My Last Visit VIEW THREADS SINCE MY LAST VISIT
           Start a New Thread

 Display posts from previous:   


  
Last Thread | Next Thread  >  

  
  

 


If you enjoy this site, please consider pledging your support

cyclingforum.com - where cyclists talk tech
Cycling TTF Rides Throughout The World

Cyclingforum is powered by SYNCRONICITY.NET in Denver, Colorado -

Powered by phpBB: Copyright 2006 phpBB Group | Custom phpCF Template by Syncronicity