Testing spoke tension by plucking it
 

I've read that the best way to check spoke tension is to pluck it like a guitar string and listen for the note. Problem is, I don't have anything to show what the proper note sounds like. Anyone know if there's an online place with mp3's of diff. notes? I'd like to play it to compare.

Also, what's the proper note? I've found this: http://www.bikexprt.com/bicycle/tension.htm#pitchtable

It separates it by whether it's butted or not. I have a Bontrager Select Wheel but have no idea if the spokes are butted (couldn't find the info on their site). Anyone know?

Tech at my local shop also said this method is unreliable. I'd like to know: who's right? I don't want to invest $$ into a tensiometer.

(FWIW, I only match the pitch between adjacent spokes. I don't know the "correct" pitch either.)

C-Sharp.

There's no way that one note works for all spokes. Some spokes are diff. lengths and some are butted or double-butted, etc.

Exactly. I seriously doubt anyone would go to the trouble of recording all the possible sounds every kind of spoke makes under various tension levels...

What I did when building my first wheel, was keep tightening spokes while maintaining wheel true in both directions. When spokes were making sound vaguely similar to the one my existing wheel did, and seemed to be similarly hard to squeeze, I took it to the bike shop. Mechanic there looked it over and said he'd recommend one more turn per nipple.

HTH

No idea if this is accurate, but it's pretty extensive: http://www.bikexprt.com/bicycle/tension.htm#pitchtable

Being a music person, this is the method I use. In fact, the last wheel I tensioned was done sitting next to a piano and comparing the pitches. If you want, go to your local music shop and pick up either a pitch key or a an electronic metronome/pitch generator. It'll cost no more than $15 for a basic one. The one sitting on my desk right now is a KORG metronome MA-30.

Isn't there some kinda calculation you can use using steel's modulus, spoke length, tension, width and calculate the 1st harmonic or overtune frequency at a specified tension? I would bust out my 1st year physics book but i'm lazy, i'm sure some1 else knows

Well, I have a table of one note sample :) If you want to hear the drive side of a 3x 36h Deep-V/Ultegra wheel, with 2.0/1.8/2.0 DTs at 110kgf. This one is within 2% all the way around:
http://www.youtube.com/watch?v=9cC6MynIUsU

I will sometimes strike the spokes with a wrench and check the ones that have a dull sound or different sound that the rest, usually find the looser ones that way.

D Flat

I think it's BS. It may be good to notice that all the spokes are relatively close to the same note but there is not one note to aim for given the fact that spoke lengths and thicknesses are different for so many different wheels.

OP - the only indication I think you get by plucking spokes is to gauge relative tension. If I find one that is substantially different in tone, I try to figure out why. Could be the spoke is loose - and needs to be tightened. Could be the rim is a bit out of true there - and the OTHER side needs to be tightened. Pluck, listen, figure out why there's a difference and fix the cause.

If the rim is true radially and laterally, and the spokes are destressed properly they are at the correct tension. Having the same tension on each spoke will either get you an out of round wheel or problems at the rim joint.

No rim is 100% perfect to start out with so there will always be differences in spoke tension, especially near the joint and on the opposite side of the joint. In an ideal world, every spoke with the same length would have the same tension.

Truing by ear gets you nothing more than squeezing pairs of spokes by hand does.

Beat it with a hammer!!! It'll make all kinds of noise then.

Isn't there an old episode of The Steve Allen Show, or maybe What's My Line?, where a young Frank Zappa came on and "played" a bicycle by plucking the spokes?

+1 on radial + lateral.Any other "off key" method could cause failure,and mash your nuts on the crossbar.

Hey! This is the wheel you built for me!

Oh, and after about 7,000 miles or so and lots of bad roads, they are still true! :D

You're getting truing and tension mixed up. You true visually. You can check tension consistency by plucking.

For wheel life, even spoke tension is much much more important than how true or round the wheel is. A wheelbuilder finds a balance that yields acceptable tension consistency, roundness, and trueness. The wheels I build are all w/in 0.25mm true/round/dish, and usually less than 5% tension variation. They are durable wheels.

If you focus on true and round, but end up with > 10% tension variation, some spokes will be slack over bumps, and will fatigue at the bend. These will break prematurely.

We had a large discussion about this in the mechanics section a couple months back. It's not the most reliable method, but it works. My understanding is that double-butted spokes should be around A while straight spokes are around G. This is an approximate range, and despite the varying lengths of spokes it still won't vary by more than one whole step in any case. It worked for me in building numerous sets of wheels with 14/15/14, 14ga, and 15ga spokes.

NOTE It did NOT work for me when using revolution (14/17/14) spokes, which would seem to prefer an F but I have not found any experts opinion on this. What it comes down to is that a tensionmeter is the BEST way to check tension, but it's not necessary. I have wheels I have built in 1995 (without a tensionmeter) and have been ridden for many miles without being trued to prove that.

I don't like that key either way. Let's just transpose up a half step and play it in D.

No, I meant tension. My hands can feel tension and my eyes can see roundness.

I don't see how you can take a true, round wheel, mess around with the spoke tension until it's closer to even and have a wheel as true.

Maybe it's more about finding a bad spoke...

Ping em one at a time till you hear one that sounds way different. Maybe that ones too tight (pitch too high) or too loose (pitch too low)

Agreed. You can't have the EXACT same tension and still have a perfectly true wheel. Tension is obviously an approximate number to shoot for, with slight variances needed to make a round and true wheel. That;s why I don't understand people saying they need to be exact.

WOW, Bob,
Thanks for the walk down memory… Frank was a genius on many levels. I believe he could play anything he put his mind to. His sense of humor and timing being uncanny at times. I saw him I think when Michael Franks was playing near by and he did a great vibe/jazz thing totally impromptu based on Michael’s music, it was truly magic. (He did the same with Cash and many others.) Thanks for taking me back.

As for the thread… everything has harmonics, why wouldn’t the spokes on a wheel?
I am going to take my sons old guitar tuner and see how close the spokes are on Campy wheels! What a great idea. Blessings.

You said "truing by ear," which is not possible.

Exactly, and you should balance the three variables as best you can, but give up round and true in favor of tension if there are issues in there. A tiny bobble is not an issue, but but undertensioned spokes are a huge issue. I've re-tuned perfectly round and true wheels that had horrible tension variability (AC Sprint 350s). When I was done, they were just as round and true, but nearly perfectly tensioned.

It is possible to have a systemic tension problem that comes from a symmetrical oval shape to the wheel. In these conditions, it's possible to retain roundness and true, while improving tension regularity. If you build the wheel focusing on all three variables throughout, you will avoid this situation altogether.