Guitar Tuner for spoke tension measurement

[Pauluk]

Having trued my first wheel at the weekend (It wasn't out by much) I've read a few threads on here and Sheldon Brown regarding spoke tension. I don't really do enough of this at the moment to consider laying out for a spoke tension meter but I would like to keep my wheels true and repair minor buckles if necessary.

The thing is, I tried a friend's £7 guitar tuner today to see if it would register and give me a consistent result when plucking the spoke and to my surprise it did. At least with the front wheel and the left side of the rear wheel.

Now the result obviously doesn't translate easily to the required units of mechanical force, but I believe the results may show the relative variations that exist in the spokes to at least one semitone.

I did the test with the tyre in place and I would expect even better results without a tyre. May be?

I should add, I'm virtually tone deaf so just plucking or tapping a spoke and listening doesn't really work for me.

My question is, is this idea flawed or even completely potty, or has anybody else used this idea before.

 

[derrick]

It's differant. lol

 

[Davidc]

The idea's been around for a very long time. This article gives the notes and if you need them look up the frequencies of musical notes using google!

I have used a piece of audio test software, laptop and microphone in the past, and it works well. No reason why a guitar tuner shouldn't do exactly the same job.

 

[deptfordmarmoset]

I recently got a new bike with handbuilt wheels and out of curiosity I tapped the spokes when it arrived to hear what difference there was in tension. For the front wheel there was less than a tone's difference between all the spokes. On the rear, there was a noticeable difference between the two sides - understandable, because the spokes on one side have a different diameter.

I reckon that checking by ear or tuner could be a very good starting point - with fine tuning by eye to follow. IF you know what pitch is going to give you the right tension, that is.

Mind you, the bike in question is only a couple of feet away so I just gave it a random set of twangs. That even tuning on the front wheel now has at least one oddity after 600 or so miles yet still seems perfectly true to me.

 

[albion]

Sounds useful if you get a numeric reading.

Like I suspect with a spoke meter(never used one) I imagine you have to reference record the tension in each and every spoke on a perfectly trued wheel.

 

[HovR]

This should work well for truing, as in essence you want all the spokes to be (roughly) the same tension. Obviously if they are the same tension they should produce the same note when plucked.

If whilst you go around your wheel plucking the spokes one is wildly out, the guitar tuner will recognize this as the spoke will produce a different note.

I personally do it by ear, however if you are not able to do this using a guitar tuner is a perfectly viable way.

 

[accountantpete]

The only problem is that I have had many factory wheels which have been fast and true and there has always been at least one spoke out of tune. I personally don't think you can true a wheel that way - bit it does get you roughly to the point where just a bit of fine tuning (no pun intended) is in order.

 

[Melonfish]

The idea's been around for a very long time. This article gives the notes and if you need them look up the frequencies of musical notes using google!

I have used a piece of audio test software, laptop and microphone in the past, and it works well. No reason why a guitar tuner shouldn't do exactly the same job.

ah that article answered my question, i was going to ask what frequency it should be on, turns out to be standard 440mhz
i have a clip on piezo tuner which would do this very nicely indeed.

 

[dodgy]

Perfectly round, strong, equal tension in spokes. Pick any 2

 

[PpPete]

Perfectly round, strong, equal tension in spokes. Pick any 2

Far too simplistic !

Wheels should be:

• Correctly dished
• Radially true
• Laterally true
• Even spoke tensions

It is not possible to get any of those 100 %perfect individually, let alone all together.

• Strong

You can't build "strength" into a wheel - in fact I don't know how to define strength other than by saying a "strong" wheel is one which does not break spokes and stays true..... and those properties are a direct result of getting more or less even spoke tensions.

You can certainly achieve even enough spoke tensions by reference to the note they give when plucked like a guitar string.

My limited experience is that with good quality components you can get dish and trueness down to around 0.5mm and spoke tensions to within a semitone either side of "ideal" (440 Hz for front and DS rear with DB spokes according to the John Allen article) and that a wheel built like that can** stay true without intervention until the rim wears out.

Unfortunately I am cloth-eared enough that I wouldn't know a semitone if it came and bit me on the bum so, until I bought a spoke tension meter, the final stages of my wheelbuilding always used to require input from my better half who has near perfect pitch.

**assuming no accidents or truly massive pothole interactions.

 

[dodgy]

Whoaa! Chill out fella haha. Was just paraphrasing Roger Musson's book, he points out that when you build a wheel purely on tension and try to get it even, it seldom results in a true wheel.

 

[lulubel]

The only problem is that I have had many factory wheels which have been fast and true and there has always been at least one spoke out of tune. I personally don't think you can true a wheel that way - bit it does get you roughly to the point where just a bit of fine tuning (no pun intended) is in order.

The goal isn't to true the wheel - you do that by eye, just checking the spoke tensions to see which ones are causing the problem when you find one. The goal is to get the spoke tensions the same, which reduces the risk of the wheel going out of true, and is the reason why handbuilts generally stay true for longer than factory builts.

 

[Linford]

If you have a smart phone on Android, you can download the free 'DA tuner' which is rather excellent

 

[Pauluk]

If you have a smart phone on Android, you can download the free 'DA tuner' which is rather excellent

Just tried that app, but can't seem to get consistent results

 

[Linford]

Just tried that app, but can't seem to get consistent results

Damn. It does work perfectly on my guitar. You will of course alter the tension across the whole wheel with each spoke as they are so tough and a wheel is a relatively fragile thing.