mzeffex 

I'm stumped. My boss is stumped. My coworker is stumped. Every fourth hole there is a loose spoke. Everyone, including myself, sees it is laced correctly. The spokes are the right length, 262/265, on a disc wheel. Everything is in place correctly. Every spoke goes into the right hole. Yet it doesn't work. Any ideas?

AEO

picture is worth a thousand words.

262/265 is a big difference for a disc wheel.
there's less dishing on that than a road rear wheel, which ends up in the 2mm length difference range

now how does a disc wheel with less dish end up with a bigger difference between left and right spoke lengths?

urbanknight

Every fourth hole tells me that, more likely than not, every other spoke on one side is too loose while the remaining spokes on that same side are too tight. I would take that side and loosen the fist tight spoke 1/4 turn, then tighten the next one on that side 1/4 turn. Continue until you're all the way around, check for tension and true, then repeat as necessary.

mzeffex 

This is using the DT swiss spoke calculator, and that's what it gave me. I picked my spokes, hub, and rim, from the drop menu, as they are all DT. That's what it said. The flanges are different sizes. And, Urbanknight, I loosened all of the spokes so they are equal, except the fourth is just loose. I left it at work, so can't get a photo.

mzeffex 

If this helps, when you tighten all the spokes all the way, every fourth, when the nipple is all the way down so it runs out of the threads, it is still not really tight. Not real loose, but not tight enough that it will be able to be trued/dished.

AEO

different flange diameter, ok, that explains things a bit better.
could be the spoke length is wrong.

mzeffex 

It shouldn't be though. I didn't even have to enter the flange diameter, hub width, flange to center, all that mumbo jumbo. Just picked my rim and hub from the dt swiss drop down menu. Just to be sure though, my boss did it all by hand. He got the same thing. I'm sure the spokes are right.

AEO

did you check the lengths with another calculator?
did you measure the ERD and flange dimensions yourself?
manufacturers are known to change the spec on you without warning.

measure more than once, cut once rule...

mzeffex 

Yes. It was both calculated using DT's measurements for those parts, and from doing my own measurements and entering it into the calculator, and my boss doing it as well. I am positive it's not the spoke length. Why would that make it every fourth spoke?

If it is of any help, it's a brand new DT x430 rim and the hub is from my old wheel before I crashed it mtbing a couple weeks back. It's a DT swiss onyx 100mm disc.

Pete Hamer

I've seen that twice but never really figured it out. At first I thought maybe the hub flanges were twisted or the spoke holes in the hub were drilled wrong. My last thought was that one set of spokes or a few spokes that are in opposition to each other got tight before the others and prevented the hub from rotating to proper position.

I'd love to hear what you come up with.

mzeffex 

I suppose it is possible the hub flanges are twisted. I tacoed the wheel and bent the qr. Wouldn't be surprised. I'll go through further investigation. Going mountain biking on sunday, so, worst come to worst, I'll put the ol' V brake and old wheel back on.

AEO

hmmm... puzzling, I see why everyone is stumped.

obvious solution would to be use 1mm or 2mm shorter spokes then.

Retro Grouch 

Hmmm. That's one that I've never encountered before.

Every 4th spoke" tells me it's a systematic thing. That would indicate a laceing problem but you say that's been checked multiple times. That usually yields 2 tight spokes and 2 loose spokes all the way around. If the dish isn't right yet, that might be what you have but it's not showing up because the rim is pulled over to one side. If that's the case, you need to unlace one side and move all of the spokes over 1 hole.

How do you bring the spokes up to tension? I tighten each nipple until there's 1 thread showing, then count the turns as I bring each spoke up to tension in small increments. That's a slow way to tension the wheel but it pays that time back during the trueing process.

Uh - when you figure it out (and I'm sure that you will) would you do us the favor of shareing your experience - even if it's something stupid that you did?

cbchess

sounds like a lacing problem - any chance you swapped the last set ( or first set )of spokes for the longer ones (265) when you should have been using the shorter set (262)?

operator

With the wheel true laterally and raidally i'd like to see a polar graph of the spoke tensions of the entire wheel.

Al1943

I'd like to see a picture of the lacing.

jroth

Sounds like a lacing issue.

mzeffex 

ill get photos later. dont think i switched the spokes. then there would be tight ones?

AEO

grab the rim, twist the hub as best you can to tug on the lose spokes.
if the loose side tightens and tight sides loosen, spokes are too long, need shorter.

the hub is usually twisted in bias to the spokes on the inside of the flange when not in tension.

mrrabbit 

3-4 closeup pictures please...

=8-)

mzeffex 

I completely forgot to get photos, work was busy. Plus I was in a rush to meet up with some friends right after. We did determine, though, that it is something laced wrong. If tomorrow is quiet (Rain expected) then we'll take half apart. We can't see what's wrong, but obviously something is.

mzeffex 

This is the only photo I have, from day 1. Not sure if it will be of any help.

mrrabbit 

1. Flash off - same picture - better focus. Be sure to hit the flower button on your camera.
2. Closer picture of the lacing with focus on the hub.
3. Closer picture of the lacing at the valve stem quarter of the wheel.

=8-)

Pete Hamer

How did you come to the conclusion that it's laced wrong?

mzeffex 

Because that's the only thing that's plausible, really. The flanges are definitely straight, the rim is brand new and is not damaged, and the spokes are definitely the right length.

As for the picture comment, that's a cell pic, so it's close 'nuff. The wheel is at work - but I'll get pics tomorrow.