Tensionmeters!!!!!

General cycling advice ( NOT technical ! )
spokesman65
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Tensionmeters!!!!!

Postby spokesman65 » 3 Apr 2013, 4:40pm

Does anyone know where I can get my grubby little hands on a Hozan tensionmeter? I've tried Planet X but they no longer supply Hozan tools. I would use a DT Swiss one but have you seen the price?
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freeflow
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Re: Tensionmeters!!!!!

Postby freeflow » 3 Apr 2013, 5:11pm

I have a Parks Tools one. It confirmed that my ability to hear pitch is better than the accuracy of the tensiometer.

spokesman65
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Re: Tensionmeters!!!!!

Postby spokesman65 » 3 Apr 2013, 5:21pm

That's the train of thought I'm tending to lean more towards. All the wheels I have built to date are still true and good, without the use of a tensionmeter I hasten to add. Maybe feel and a good ear are more important!
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531colin
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Re: Tensionmeters!!!!!

Postby 531colin » 3 Apr 2013, 5:48pm

freeflow wrote:I have a Parks Tools one. It confirmed that my ability to hear pitch is better than the accuracy of the tensiometer.


I'm tone deaf, so I can't really join in this conversation!
Also, I packed up building wheels professionally more than a year ago now, and the memory fades.....I think if I repeatedly gauged the same spoke with the Park tools gauge, then the spread of readings was about 5%....is that about what you get?
I don't think theres any future in trying to get the tensions to match up any closer than 5%, I think myself extremely fortunate if I find a rim straight enough to build a wheel that is true and stress-relieved and has the tensions as close as that!

JonMcD
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Re: Tensionmeters!!!!!

Postby JonMcD » 6 Apr 2013, 12:55pm

531colin wrote:
I don't think theres any future in trying to get the tensions to match up any closer than 5%, I think myself extremely fortunate if I find a rim straight enough to build a wheel that is true and stress-relieved and has the tensions as close as that!


It might not be just the straightness of the rim that frustrates matched readings on the tension meter, or matched pitch come to that. These indirect methods of matching tension depend on the spokes having the same diameter. Putting a micrometer on the central section of the spokes I have to hand give measurements of diameter from 1.70 to 1.75mm for ACI Alpina DB and 1.82 to 1.85mm for DT Swiss Alpine III, both on the same spoke and on different spokes. The conversion table for the Park Tools tension meter shows just how sensitive the tension readings are to changes in spoke diameter for the same deflection reading.

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hubgearfreak
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Re: Tensionmeters!!!!!

Postby hubgearfreak » 6 Apr 2013, 1:20pm

spokesman65 wrote:All the wheels I have built to date are still true and good, without the use of a tensionmeter I hasten to add.


then you haven't got a need for a tensionometer.

ukdodger
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Re: Tensionmeters!!!!!

Postby ukdodger » 6 Apr 2013, 1:41pm

spokesman65 wrote:Does anyone know where I can get my grubby little hands on a Hozan tensionmeter? I've tried Planet X but they no longer supply Hozan tools. I would use a DT Swiss one but have you seen the price?


I've found the Park one plenty good enough. You can do it by sound but personally I like using the meter. It doesnt make mistakes.

RRSODL
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Re: Tensionmeters!!!!!

Postby RRSODL » 6 Apr 2013, 4:53pm

hubgearfreak wrote:
spokesman65 wrote:All the wheels I have built to date are still true and good, without the use of a tensionmeter I hasten to add.


then you haven't got a need for a tensionometer.


There is some true in this statement.

I used to use a tensiometer but over time I stopped using it unless it is the very last check. I found that tuning by tone and averaging the spoke tension by tone works very well for me. I use the tensionmeter to have an ideal of what my final tension is. The nice thing I find is that by doing it this way the final tension is very even all round the wheel. The final check is just a reassurance that my ears are still working :lol: and to tell me that I stopped a few lines over the mark it's indicated in the Parks table :)

So, it you can build wheels without a tensiometer already then perhaps you need to borrow one to test but my guess is that after a few times you will find that a musical ear and good hand feel is better than a tensiometer.

mig
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Re: Tensionmeters!!!!!

Postby mig » 6 Apr 2013, 8:40pm

gerd schraner wrote that he used to think that he built wheels well by 'feel' until he used a tension checking tool which led him to always use one.

as for the pitch technique - how is the spoke being plucked/tapped? does it not make a difference as to where along its length this occurs?

RRSODL
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Re: Tensionmeters!!!!!

Postby RRSODL » 7 Apr 2013, 12:00am

mig wrote:gerd schraner wrote that he used to think that he built wheels well by 'feel' until he used a tension checking tool which led him to always use one.

as for the pitch technique - how is the spoke being plucked/tapped? does it not make a difference as to where along its length this occurs?


I agree with your comments. I guess that a good way to know your hearing is working ie, the tension is even on the wheel would be to check with a tensionmeter.

As for the second part of your post, I also agree with your observation. The way I do this is resting 3 fingers on the stand while holding a guitar pick with the other two fingers, then it's just a question of rotating the wheel slowly. My nails are never long enough hence the use of a guitar pick :)

You won't get the same pitch on every spoke but you would be surprised at the results. I guess that some people can't do this well and in that case then a tensiometer is a good alternative.

For a beginner on wheel building, a tensiometer, would be a good tool to have.

Moodyman1

Re: Tensionmeters!!!!!

Postby Moodyman1 » 7 Apr 2013, 12:11am

Like Colin, I too must be tone deaf so I could not detect the tension via plucking.

I bought the Park tools one and the dreaded sound of pinging spokes suddenly stopped. Having said that, I had my first breakage in 2.5 years last week but it was a horrendous pothole that caused it.

Gearoidmuar
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Re: Tensionmeters!!!!!

Postby Gearoidmuar » 7 Apr 2013, 7:13am

I've never had a tensionometer but pluck. If you try to get the wheel completely true then you will not have all the spokes at exactly the same note. If you try to get them all at exactly the same note, then it will not be exactly true. This is not only my opinion but that of one of the top wheel companies who make racing wheels. The differences are due to minor variation in thickness , etc.
So, what's the criterion to aim for?
It's that all the spokes on the same side be within a tone (doh-ray) of one another and that the wheel be true. This works. I don't break any spokes if I build a strong rim like this and I stress relieve it properly and I average 14.7 and was 15.10 for years and did a lot of touring.

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531colin
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Re: Tensionmeters!!!!!

Postby 531colin » 7 Apr 2013, 8:03am

I can tell songthrush from blackbird, greenfinch from goldfinch, dunnock from robin just by their song, or even flight note in the case of the finches.....but if you play me 2 notes on the piano I struggle to say which is higher.....but I've met people with perfect pitch, so I know it can be done. (One was a blind lad....nobody had ever mentioned to him that birds sounded different....that was an interesting conversation.....he was very soon better than me at telling birds apart...)
If you can balance tension by pitch, do you have to use a tension gauge to put an actual number on the tension, eg so you don't exceed rim manufacturers specification for light rims? (I suppose next time you build the similar wheel, you would remember the pitch?.....this is so completely outside my experience, I can't imagine being able to do it!)

I'm afraid its most unlikely that a single exposure to a very high peak load will snap a spoke....most spokes that break even in accidents are already fatigued.

pete75
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Re: Tensionmeters!!!!!

Postby pete75 » 7 Apr 2013, 9:29am

hubgearfreak wrote:
spokesman65 wrote:All the wheels I have built to date are still true and good, without the use of a tensionmeter I hasten to add.


then you haven't got a need for a tensionometer.


Exactly!!!

Brucey
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Re: Tensionmeters!!!!!

Postby Brucey » 7 Apr 2013, 9:32am

Colin's comment re the blind guy and the bird song is very interesting. Maybe no-one had told him that there were different birds, even. I'm not surprised he cottoned on quickly through. Very often people's ability to hear is a 'brain thing', not an 'ear thing'.

My understanding is that early in life, the brain is 'wired up', usually in a predisposed fashion. However, not everyone gets their brain wired up in quite the same way; through chance or other factor people make different connections and this makes people tend towards different abilities. Commonly in people blind from birth, the visual cortex (one of the most powerful and active parts of the brain, normally) is used to process sounds instead, hence apparently 'better hearing' in some blind people.

Re spoke tensions. I wrote a short piece on note vs tension here;

http://forum.ctc.org.uk/viewtopic.php?f=5&t=72025&p=624714&hilit=tension+pitch+note#p624714

and of course the topic has come up many times before. A semitone is worth 5% on tension BTW. It is a very good way of determining relative tensions between spokes.

Re tension meters; there is a tendency to 'believe the magic tool' come what may; this would be a mistake. Most spoke tension meters cannot discriminate between variations in tension and variations in either thickness or straightness. The latter shouldn't matter if the spoke is both thin and tight I guess, but that isn't always the case. If I needed to get the absolute tension very accurate for some reason, or I had no starting point, maybe some means of measuring tension is useful. But otherwise tension uniformity is at least as important.

cheers
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