67tony 

I'm switching rims, but re-using the hub and spokes.
Currently, where the spokes cross, there is some slight wear.
When re-lacing the wheel, should I reverse the way the spokes cross, so they don't continue to wear?

juvela

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moot

reuse of spokes increases likelihood of spoke breakages

some enthusiasts do it all the time

some enthusiasts would na'er do it


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Nwvlvtnr 

Addressing only the reuse of old spokes I find it best to keep them in the same position as before. Not having seen your spokes I’d be hesitant to reuse them if it looks like material is missing from corrosion where they intersect.

kunsunoke 

Leave the crossings alone.

If the spokes are the cheap kind (plated steel) you're not likely to extend their lifespans by any appreciable degree.

If the spokes are stainless, it won't make that much of a difference anyway.

oneclick 

Spokes which are interlaced at their crossings deviate from a straight
line.

The forces resulting from this situation can be calculated.

Assume the following:
a) spoke diameter of 2mm;
b) flange thickness of 3mm;
c) spoke length of 300mm;
d) crossing at 200mm from the rim;
e) spoke tension of 100kgf
f) Young's modulus of 200*10e9 N/m^2

The centre-line of an uncrossed spoke lies at an angle to the line
between the flange centre and the spoke hole at the rim, such angle
having a height at the flange of half the flange thickness plus half the
spoke thickness; given the figures above this is 2.5mm and the angle is
0.48 degrees.

The centre-line of a crossed spoke deviates from the straight line
between the flange centre and the spoke hole (in the rim) at the crossing
point by the spoke thickness plus an amount proportional to half the
thickness of the flange (in this case 2/3rds as the crossing point is at
2/3rds of the spoke length); given the figures above we have a deviation
of 3mm total and an angle of 1.72 degrees at the flange. There is a
second angle calculable from the crossing point between the centre-line
of the spoke to the spoke hole in the rim and the line joining the flange
centre and the spoke hole; given the figures above it is 0.29 degrees.

So we have a triangle; taking the centre-line of an uncrossed spoke as a
reference the angle A (at the flange end) of a crossed spoke is
(1.72-0.48 = 1.24) degrees and angle B at the rim end is (0.48+0.29 =
0.77) degrees.

The orthogonal force at the crossing point can now be calculated as (t
sin A + t sin B); given the figures above it is roughly 3.5kgf.

The difference in length between the centre-line of an uncrossed and a
crossed spoke, given the figures above, is 100 * 1/cos(1.24) plus 200 * 1/
cos(0.77) giving a new length of 300.04 mm.

The proportion of the tension in the crossed spokes due to their crossing
is calculable: t=(a*e*dl)/l, which given the figures above is about 8.5
kgf.

The point loading at the crossing for perfectly round and incompressible
spokes is infinite, but the actual degree of osculation at the pressure
found above can be estimated. The yield strength of stainless steels can
vary tremendously depending on the alloy and manufacturing; cycle spokes
are typically 314 or similar steel and are cold-worked; a not-
unreasonable estimate for yield strength is 300 MPa, which is about 3000
kgf per cm^2. The load of 3.5kgf found above can therefore be supported
by an area of 1/10 mm^2, which if circular would show on the spoke as a
bright spot 0.05mm in diameter.

The crossing point of the spokes may move as the spokes are unloaded at
the bottom of the wheel. This effect is greatest for lacing patterns of
high cross values, as the spokes join to the rim at points far enough
apart that one spoke is unloaded preferentially. Taking the extreme case
where one spoke is unloaded such that is assumes the line taken by an
uncrossed spoke and given the figures above, the bright spot will move
towards the flange by .0234 mm; this means that should such excursions be
common the bright spot would approximate an ellipse of minor diameter
0.05mm and major diameter 0.0734mm.

steelbikeguy

Generally speaking, it's unlikely to be an issue. Still, I'd be interested in hearing from anyone who has had a spoke break from this wear.

re: reversing the spokes... is that even possible? The only way I can think of to change where the spokes rub would be to change the number of crossings, such as going from 3x to 2x. However, that would require shorter spokes.

As far as reducing wear... one option would be tying and soldering the spokes. Sounds like a good excuse to try something different!

Steve in Peoria

100bikes

Rims have a specific ERD(effective rim diameter).
If the original rim and the new rim have significantly different ERD measurement, the spokes
might not/will not work. They could be either to long or to short when laced with the same cross
pattern.

IE- a lower end, flat rim vs a box section rim with eyelets or even more noticeable would be
anything compared to a Weinmann Concave!

rusty

67tony 

Spokes are stainless, and I'm going from an Open Pro ceramic to an Open Pro alloy.
What I originally thought was wear turns out to be slight rust rather than grooves.

When I considered switching the crossing spots, I meant reversing the crossing closest to the rim, so that any wear spots would now NOT be rubbing on each other.

After reading the comments, I see now that it probably will not matter.
Thanks for the help!

(oneclick, great information...trouble is, you lost me after "calculated"!)

SJX426 

@67tony - Rust on stainless spokes? Must be dirt. Pics or it isn't true.

old's'cool

It wouldn't surprise me if fretting combined with galvanic activity would result in formation of iron oxide at the contact point.

oneclick 

Stainless will rust given conditions appropriate; one of which is removal of the thin layer of chromium oxide, which if intact would prevent further oxidation - this layer is so thin that it does not appreciably change the colour.

And of course "stainless" covers a wide variety of alloys, which vary in their corrosion resistance. Spokes commonly use an alloy with a high percentage of chromium and nickel - iron may be as little as 50%; and so are quite resistant to corrosion, but it does not conquer, it just resists:

scarlson 

I reuse the spokes in the same positions. I have a different reason though. My reason is that it takes much longer to relace the whole wheel than it is to just tape the two rims side by side and switch the spokes over one by one. Your time is worth something! I've never had a problem doing this.

top506

This. Works for me as well.

Top

67tony 

Probably right, mostly dirt.
With that said, though, I still feel that some of the crossings have a tiny groove worn in, as evidenced by a slight clicking sound.

gkamieneski

Line up the valve holes and have hole offsets equal on both old and new rims, tape together in 3 spots, then transfer spokes one at a time as many have said. Any spoke that spooks you, just replace that one.

67tony 

Trouble is, I'm transferring the spokes AND the hub over to a new rim.
Any clever ideas on how to best accomplish that task?

gkamieneski

Yes. That is what I am suggesting you do by my instructions. Old hub, old spokes, new rim. Used to have to do this frequently in the days of Mavic MA40, MA3 rims etc. These rims would often “splinter” at a spoke hole and when you caught it and realized it, you would do a “rim lace over”. Fortunately those Mavic rims never cost very much. Used to do so with Mavic tubular rims as well, such as GEL330s and Reflexes but not as often was it needed.

alcjphil

Tape the 2 rims together with the spoke holes lined up with each other. Then, one by one unscrew the spoke nipples and move them from the old rim to the new one. This will be easier to do if you loosen all the nipples a couple to turns before you start the transfer process. Once all the spokes have been transferred you can start to true the wheel and tension the spokes

oneclick 

In addition, do all one side spokes first, the side closest to the new rim (just get them in and do a few turns). Doing both sides one-by-one is a lot more bother.

madpogue 

And make sure you select a rim that's "handed" in the same direction as the existing one.

67tony 

Worked like a charm, thanks a ton for all the help and advice!

awac

When I strip a rim to clean the hub and/or rim keeping the spoke in the right order is difficult so I have made these mk1 spoke position holders! A chef I know was having a deep fat fryer replaced and these were the fat traps (this is why it has so many holes) that go inside the business part. I fixed them to the wood to test it. I will route out a trough so they do not need to hang over an edge, and probably make it hold oil so the spokes are lubricated when building a wheel. You could, if you want put the spokes in the holes in the order they come out, I think head in/out L/R F/R is enough personally.

So much easier than elastic bands, it works well for me.



Used spoke holder

Used spoke holder

scarlson 

Whoa! And I thought I was fancy for using tape or rubber bands!

dddd

Most of this is new to me.

Whenever I have to mess about with swapping parts of used wheels, I always start by drinking heavily, so that I won't notice how much time that I'll be wasting and so can feel much better about the job completed.

awac

My OCD made that so laborious, putting tape on each spoke and numbering it…..lol.