DOS

I am building a 36h wheel that spoke calculator tells me I need spokes between 298 and 299mm (so I could use either without a problem). It is a front wheel so will have same size spokes on either side. I have in my posession 26 spokes that I salvaged from the wheel I am rebuilding. I thought they were 298s but was wrong, having apparently mismeasured when many months ago I disassembled the previous wheel (reusing hub with differnt rim of same model as previous). They are 299mm. So I orderd a handful more 298s in order to build the wheel before I discovered my previous measuring error and they are on their way. But come on, how much difference in 1mm. If I lace up a wheel using 26 299mm spokes and sneak in a 298mm every thrid spoke or so, that can't be bad right? Seriously, will I be able to get the wheel true and tensioned? I know I know, I should just order the right spokes but I am sort of curious.

ThermionicScott 

You might get away with it but the bigger question is whether they're the same thickness -- you'll be hating life if you need to tension 1/3 of your spokes a different way with a different wrench.

- Scott

DOS

Same thickness, so no worries there.

ThermionicScott 

Ah, that's good! I guess my next concern would be that they won't be threaded to the same spot -- when they are, it makes starting out a lot easier. If you mark the shorter ones and use a tensiometer to keep from over-tightening them, that ought to keep you out of trouble.

- Scott

hueyhoolihan

wheels can be lace 1,2,3,4 cross depending on diameter of the rim. each requires different lengths for any given rim. and with long nipples (16mm i think are the longest) there is quite a bit of leeway as far a what length will work and what won't.

i'm not too picky and will try different lacing patterns if i have a set of spokes that are too long or too short. if you fool around with one of the online spoke length calculators and plug in various lacing patterns and nipple lengths using the same hubs and rims you can get a sense of how many spoke lengths are viable.

SBinNYC

Wheel building is based on the premise that the spokes are the same length and the spoke holes are uniformly distributed around the rim. If you initially tighten all the spoke nipples to exactly the same point, then you should have a very good wheel and the truing operation is to compensate for manufacturing tolerances. If you start with spokes of unequal length, then the initial lacing will not yield a nearly true wheel.

I'd keep track of the 10 shorter spokes. I'd tighten all the spoke nipples the same amount by counting the threads either visually if your eyes are good enough or by using a mechanical aid. Then before I start any truing, I'd loosen the shorter spoke nipples two and one quarter turns to compensate for the 1 mm shorter length. This starting point would make all spoke lengths nearly equal and make for a fairly easy build.

Two and one quarter nipple revolutions is a lot to be off after the initial lacing. I'd be very wary of trying to use a tension meter to keep track of spoke length differences.

DOS

Thanks for input. I am convinced it can be done; whether I can do it remains to be seen. I'll give it a shot and report back.

mrrabbit 

Use 10mm or 12mm nipples...more likely than not you'll be fine.

14mm/16mm night throw a wrench into things...

=8-)

neurocop

+1 The 1mm difference in length (all other dimensions and spoke material being equal) shouldn't be a problem, but you will need either a very good "tensioning ear" and/or a tensiometer to get the tension equal, and your spokes will be at different depths. You obviously shouldn't mix aluminum and steel spokes, as the materials have different elastic properties, and I suspect that different brands of the same general material may have different elastic properties, including slightly different tones when plucked to check tension, which is why its probably better not to mix spokes, and a good idea to use a tensiometer if you do.

DOS

I built the wheel today using 27 299mm spokes and 9 298mm spokes. 298 would have been ideal as the 299s seem a bit long but the difference seems not to have made a difference. I started out keeping close tabs on the 298s to avoid over tensioning but it pretty quickly became apparent that is wasn't going to be an issue. More of a challenge was the condition of the Mavic MA40 rim I was using (vinatge parts for wheel going on 86 SChwinn Paramount). While straight, it has a ding or two that made getting a good read on radial true a bit of a challenge. The wheel is now true save for a slight radial hob due to one of the dings. Tension avg is 100kgf at about +/- 7% for any specific spoke so I am satisfied with that. I'll post again of the wheel suffers catastrtophic failure due to my use of different length spokes.

macaw1us

Tention is key and it's better to go 1mm longer than it is shorter, as long as you engage at least 5 threads you are fine.
My only reservation is using old spokes to begin with as no one knows where they are in their duty cycle of life and will be prone to fail quicker than the new spokes.
Balance the tension between the pairs and relieve the tension at the rim (stress relieve) a couple of times while doing your final tensioning of the spokes.
This should bring your +/- 7% or 14% overall much closer and you'll end up with a wheel that will last much longer for you.

Good Luck

Drew Eckhardt 

It depends.

With 8mm of thread in the nipple (to the end) and 9mm on the spoke (as with DT 12mm nipples and spokes):

If you were aiming for the top of the nipple they'll probably bottom before you get to full tension.

If you were aiming for the bottom of the nipple slot and the wheel ERD is 2mm smaller than advertised they'll bottom before you get to full tension.

If you were aiming for the bottom of the nipple slot, the ERD is spot on, and you're using straight-gauge spokes they'll end at the top of the nipples and be fine.

Drew Eckhardt 

Spokes have 56 threads per inch, so absorbing an extra 1mm of spoke length will take an extra 2.3 turns which you can round up to 2.5.

nfmisso

You will be instantly transported to
The Restaurant at the End of the Universe

.

3alarmer 

You will end up using a lot of time and mental energy
that might be better devoted to something else ?

Good luck with your science project. I'd say your chances
of catastrophic failure are minimal, but you might want to
reconsider your time management skills.

DOS

Naa, it didn't take any longer than any other wheel I have built. Which is not to say the time I spent on those was an effective use of my mental energy. I do find the process oddly relaxing, however. Also, I guess you could say in this case that I saved some time by not having to go and get or order additional spokes.

retroracer53012

Personally, as a general rule of thumb, I would never reuse old spokes... just pony up and buy new/same size and be done. Peace of mind. Also, all wheelbuilding advice aside, cosmetically you will notice the difference between the new/old spokes - if it matters. I do a lot of wheelbuilding for restoration builds and this would drive me nuts. IMHO.

mrrabbit 

So if I brought you new and used DT 14g spokes...

...and took the used one's and swiped them through a semi-crhome infused towel and then straightened the elbows using a round bending point - you'd be able to tell the difference when both new and used spokes are built up on wheels?

=8-)