Tensiometer
#2
Senior Member
Join Date: Dec 2007
Location: San Jose, California
Posts: 3,504
Bikes: 2001 Tommasini Sintesi w/ Campagnolo Daytona 10 Speed
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 145 Post(s)
Likes: 0
Liked 35 Times
in
30 Posts
Will it work in the confines of a 20" wheel?
=8-)
=8-)
__________________
5000+ wheels built since 1984...
Disclaimer:
1. I do not claim to be an expert in bicycle mechanics despite my experience.
2. I like anyone will comment in other areas.
3. I do not own the preexisting concepts of DISH and ERD.
4. I will provide information as I always have to others that I believe will help them protect themselves from unscrupulous mechanics.
5. My all time favorite book is:
Kahane, Howard. Logic and Contemporary Rhetoric: The Use of Reason in Everyday Life
5000+ wheels built since 1984...
Disclaimer:
1. I do not claim to be an expert in bicycle mechanics despite my experience.
2. I like anyone will comment in other areas.
3. I do not own the preexisting concepts of DISH and ERD.
4. I will provide information as I always have to others that I believe will help them protect themselves from unscrupulous mechanics.
5. My all time favorite book is:
Kahane, Howard. Logic and Contemporary Rhetoric: The Use of Reason in Everyday Life
#3
Senior Member
Join Date: Oct 2011
Location: SF Bay Area
Posts: 428
Bikes: 2003 Lemond Zurich; 1987 Schwinn Tempo; 1968 PX10; 1978 PX10LE, Peugeot Course; A-D Vent Noir
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Likes: 0
Liked 1 Time
in
1 Post
A spoke tensiometer is a simple device that allows you to place a spoke across two pivots, apply a perpendicular force to the pivoted spoke, and measure the amount of deflection. That's about all there is to it. Obviously the amount of deflection will depend upon the elastic properties of the spoke, which depends upon the spoke material and dimensions. That deflection needs to be "translated" into a "tension" measurement. So there is no way to directly measure "tension" (what you measure is deflection). I am quite satisfied with the $60 Park tensiometer. Fancier tensiometers, with digital deflection readouts may be easier to read, but you still need to use deflection/tension conversion charts.
YMMV.
YMMV.
#4
Senior Member
Join Date: Aug 2011
Posts: 1,141
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Likes: 0
Liked 2 Times
in
2 Posts
A spoke tensiometer is a simple device that allows you to place a spoke across two pivots, apply a perpendicular force to the pivoted spoke, and measure the amount of deflection. That's about all there is to it. Obviously the amount of deflection will depend upon the elastic properties of the spoke, which depends upon the spoke material and dimensions. That deflection needs to be "translated" into a "tension" measurement. So there is no way to directly measure "tension" (what you measure is deflection). I am quite satisfied with the $60 Park tensiometer. Fancier tensiometers, with digital deflection readouts may be easier to read, but you still need to use deflection/tension conversion charts.
YMMV.
YMMV.
nothing wrong with analogue (sci-fi mag?). whatEVER we're measuring here, it doesn't HAVE to be spot on. this isn't a space shuttle. a guy i used to know got me into rc cars and boats. like to drove me nuts with his obsessive fussing and incessant tweaking instead of running the things. the kind of guy who'd keep sharpening a new pencil down to the eraser, trying to get the perfect point.
nice looking toy, though.
#5
Banned
Fancy tools impresses the buyer, so you can raise your rates, for labor.
Don't forget the Machine that goes 'Ping"..
Don't forget the Machine that goes 'Ping"..
#6
Senior Member
Join Date: Sep 2011
Posts: 403
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Ah, the wonderful debate of accuracy and precision, especially when overlaid with the common misconceptions about each. For the uninitiated, accuracy is how close to correct (i.e. if a widgetometer says it's 10.2 widgets on something that's 10.1 widgets, there's a 1% accuracy error), while precision is the level of detail (i.e. a widgetometer reading of 10.20 indicates four digits of precision, or that it believes that it's not 10.19 or 10.21 widgets, while a reading of 10.2 indicates three digits of precision.) I wonder what this thingy provides on the accuracy/precision scale...
#7
Senior Member
Join Date: Dec 2007
Location: San Jose, California
Posts: 3,504
Bikes: 2001 Tommasini Sintesi w/ Campagnolo Daytona 10 Speed
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 145 Post(s)
Likes: 0
Liked 35 Times
in
30 Posts
Here's the problem I have with these very "high end" tensionmeters:
I'm sure they are awesome tools, capable of very very fine estimates with resolutions of .1, .01 or even .001. In other words, they are tools capable of very very precise estimates.
Which is great, IF....IF...
...the materials you are working with were themselves manufactured consistently with very fine tolerances.
While there are certain model rims that are manufactured with very fine tolerances, you still have to deal with spokes that vary slightly within a gauge, and with spokes that vary composition-wise within a gauge.
Compound the average wheel together that we usually build - at best - all we can get are "rough" estimates of where the individual spokes are at and where the "average" is at.
The result is that you take a very fine tuned and very expensive tool - and drop it right down to the rough estimate world - right where the original Wheelsmith tensionmeter was - right where the current Park TM-1 is.
The Wheelsmith and Park, so long as they are kept callibrated, do the job just fine in that world - for a hellava lot less.
To give an example,
I have a Swiss made Pharmaceutical scale that is rated for 300g with a readout of "xxx.000" It is a very expensive piece of machinery used by Pharmacist's who need to do manual non-pill powderized drug formulations at the milligram level - usually for critical and very dangerous drugs.
I use it to quickly count CNspoke 12mm and 14mm brass nipples.
When I toss in a 12mm nipple, and then swap for another, and another...I get readings of .934 through .964.
What does that mean? I could do the same counting job with a much cheaper gram scale that has a readout of "xxx.0"
These very high quality precision tensionmeters will spend most of their time being used as show pieces, just like like dial indicators...
=8-)
I'm sure they are awesome tools, capable of very very fine estimates with resolutions of .1, .01 or even .001. In other words, they are tools capable of very very precise estimates.
Which is great, IF....IF...
...the materials you are working with were themselves manufactured consistently with very fine tolerances.
While there are certain model rims that are manufactured with very fine tolerances, you still have to deal with spokes that vary slightly within a gauge, and with spokes that vary composition-wise within a gauge.
Compound the average wheel together that we usually build - at best - all we can get are "rough" estimates of where the individual spokes are at and where the "average" is at.
The result is that you take a very fine tuned and very expensive tool - and drop it right down to the rough estimate world - right where the original Wheelsmith tensionmeter was - right where the current Park TM-1 is.
The Wheelsmith and Park, so long as they are kept callibrated, do the job just fine in that world - for a hellava lot less.
To give an example,
I have a Swiss made Pharmaceutical scale that is rated for 300g with a readout of "xxx.000" It is a very expensive piece of machinery used by Pharmacist's who need to do manual non-pill powderized drug formulations at the milligram level - usually for critical and very dangerous drugs.
I use it to quickly count CNspoke 12mm and 14mm brass nipples.
When I toss in a 12mm nipple, and then swap for another, and another...I get readings of .934 through .964.
What does that mean? I could do the same counting job with a much cheaper gram scale that has a readout of "xxx.0"
These very high quality precision tensionmeters will spend most of their time being used as show pieces, just like like dial indicators...
=8-)
__________________
5000+ wheels built since 1984...
Disclaimer:
1. I do not claim to be an expert in bicycle mechanics despite my experience.
2. I like anyone will comment in other areas.
3. I do not own the preexisting concepts of DISH and ERD.
4. I will provide information as I always have to others that I believe will help them protect themselves from unscrupulous mechanics.
5. My all time favorite book is:
Kahane, Howard. Logic and Contemporary Rhetoric: The Use of Reason in Everyday Life
5000+ wheels built since 1984...
Disclaimer:
1. I do not claim to be an expert in bicycle mechanics despite my experience.
2. I like anyone will comment in other areas.
3. I do not own the preexisting concepts of DISH and ERD.
4. I will provide information as I always have to others that I believe will help them protect themselves from unscrupulous mechanics.
5. My all time favorite book is:
Kahane, Howard. Logic and Contemporary Rhetoric: The Use of Reason in Everyday Life
#8
Senior Member
Join Date: Apr 2009
Location: New Rochelle, NY
Posts: 38,725
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
Mentioned: 140 Post(s)
Tagged: 1 Thread(s)
Quoted: 5793 Post(s)
Liked 2,584 Times
in
1,432 Posts
+1,000 i
It's become commonplace to use precision to create the illusion of accuracy. For a simple example think about the speedometer of your car. It's accuracy depends on a number of factors, some within the unit, some outside, for example whether your tires are the exact diameter it was calibrated for (they're not). So while a digital speedometer may seem more precise saying you're going exactly 66mph, ti isn't any more accurate than an analog unit that says you're going slightly faster than 65mph, because in face you might only be going 62mph.
There's also the issue of repeatability. Often, an instrument will give different readings for the same value different times for a variety of reasons. If the range of readings is within the stated accuracy it passes the test, but this could be a problem for a spoke tension meter causing a user to waste time correcting what are in face only read errors.
I'm not panning this tool, which appears to be a nicely executed piece of work. I'm just trying to remind folks that for much more dough, it isn't any better from a functional standpoint than most of the units out there.
It's become commonplace to use precision to create the illusion of accuracy. For a simple example think about the speedometer of your car. It's accuracy depends on a number of factors, some within the unit, some outside, for example whether your tires are the exact diameter it was calibrated for (they're not). So while a digital speedometer may seem more precise saying you're going exactly 66mph, ti isn't any more accurate than an analog unit that says you're going slightly faster than 65mph, because in face you might only be going 62mph.
There's also the issue of repeatability. Often, an instrument will give different readings for the same value different times for a variety of reasons. If the range of readings is within the stated accuracy it passes the test, but this could be a problem for a spoke tension meter causing a user to waste time correcting what are in face only read errors.
I'm not panning this tool, which appears to be a nicely executed piece of work. I'm just trying to remind folks that for much more dough, it isn't any better from a functional standpoint than most of the units out there.
__________________
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
#9
Old fart
Join Date: Nov 2004
Location: Appleton WI
Posts: 24,790
Bikes: Several, mostly not name brands.
Mentioned: 153 Post(s)
Tagged: 0 Thread(s)
Quoted: 3590 Post(s)
Liked 3,401 Times
in
1,935 Posts
A spoke tensiometer is a simple device that allows you to place a spoke across two pivots, apply a perpendicular force to the pivoted spoke, and measure the amount of deflection. That's about all there is to it. Obviously the amount of deflection will depend upon the elastic properties of the spoke, which depends upon the spoke material and dimensions. That deflection needs to be "translated" into a "tension" measurement. So there is no way to directly measure "tension" (what you measure is deflection). I am quite satisfied with the $60 Park tensiometer. Fancier tensiometers, with digital deflection readouts may be easier to read, but you still need to use deflection/tension conversion charts.
YMMV.
YMMV.
#10
Roadkill
Join Date: Sep 2004
Location: East Tennessee
Posts: 858
Bikes: 2002 Lightspeed Classic; 2010 Pedalforce RS
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
I spoke with one of the phone reps at Easton wheels about wheel building a few times.
I was told that the Easton builders use tone for most of the tensioning process, but that they use a tension gauge to determine the proper tone. Further, the rep claimed they have found they need to calibrate the tension gauge several times a day, as the results will wander. They calibrate using a spoke under a known tension.
I was told that the Easton builders use tone for most of the tensioning process, but that they use a tension gauge to determine the proper tone. Further, the rep claimed they have found they need to calibrate the tension gauge several times a day, as the results will wander. They calibrate using a spoke under a known tension.
#11
Senior Member
Join Date: Dec 2007
Location: San Jose, California
Posts: 3,504
Bikes: 2001 Tommasini Sintesi w/ Campagnolo Daytona 10 Speed
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 145 Post(s)
Likes: 0
Liked 35 Times
in
30 Posts
I spoke with one of the phone reps at Easton wheels about wheel building a few times.
I was told that the Easton builders use tone for most of the tensioning process, but that they use a tension gauge to determine the proper tone. Further, the rep claimed they have found they need to calibrate the tension gauge several times a day, as the results will wander. They calibrate using a spoke under a known tension.
I was told that the Easton builders use tone for most of the tensioning process, but that they use a tension gauge to determine the proper tone. Further, the rep claimed they have found they need to calibrate the tension gauge several times a day, as the results will wander. They calibrate using a spoke under a known tension.
=8-)
Sure, if you are building the exact same wheel all the time - you can establish a tone that matches. But if I bring 'em an unknown rim, hub, spokes, and specify the crossing...tone will not be the decider - tensionmeter will be.
The beauty of a tensionmeter is that it measures a deflection for a given length - regardless of gauge, length, crossings, etc.
=8-)
__________________
5000+ wheels built since 1984...
Disclaimer:
1. I do not claim to be an expert in bicycle mechanics despite my experience.
2. I like anyone will comment in other areas.
3. I do not own the preexisting concepts of DISH and ERD.
4. I will provide information as I always have to others that I believe will help them protect themselves from unscrupulous mechanics.
5. My all time favorite book is:
Kahane, Howard. Logic and Contemporary Rhetoric: The Use of Reason in Everyday Life
5000+ wheels built since 1984...
Disclaimer:
1. I do not claim to be an expert in bicycle mechanics despite my experience.
2. I like anyone will comment in other areas.
3. I do not own the preexisting concepts of DISH and ERD.
4. I will provide information as I always have to others that I believe will help them protect themselves from unscrupulous mechanics.
5. My all time favorite book is:
Kahane, Howard. Logic and Contemporary Rhetoric: The Use of Reason in Everyday Life
Last edited by mrrabbit; 01-21-12 at 02:45 PM.
#12
don't try this at home.
Join Date: Jan 2006
Location: N. KY
Posts: 5,940
Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 974 Post(s)
Liked 512 Times
in
352 Posts
For $295, they could at least let you enter the conversion factor for the current wheel's spokes, and then get kgf readings directly, without needing a spoke chart.
From the link:
The tool costs USD$295, and here is what you get:
1. A shock-proof, lockable, foam lined case with metal pin hinges.
2. 26 page Owner's Manual, with many wheelbuilding tips.
3. Laminated Spoke Tension Chart, for convenient conversion.
4. Spare battery.
5. A CD with PDF files of the manual and chart, and our instruction movie.
From the link:
The tool costs USD$295, and here is what you get:
1. A shock-proof, lockable, foam lined case with metal pin hinges.
2. 26 page Owner's Manual, with many wheelbuilding tips.
3. Laminated Spoke Tension Chart, for convenient conversion.
4. Spare battery.
5. A CD with PDF files of the manual and chart, and our instruction movie.
#13
Really Old Senior Member
I got so excited I went out and just bought the Park tool for $48.41 delivered-
www.aawyeah.com/
40inutes later, I got the email confirming it was shipped!
www.aawyeah.com/
40inutes later, I got the email confirming it was shipped!
#14
Senior Member
Join Date: May 2007
Posts: 252
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Ah, the wonderful debate of accuracy and precision, especially when overlaid with the common misconceptions about each. For the uninitiated, accuracy is how close to correct (i.e. if a widgetometer says it's 10.2 widgets on something that's 10.1 widgets, there's a 1% accuracy error), while precision is the level of detail (i.e. a widgetometer reading of 10.20 indicates four digits of precision, or that it believes that it's not 10.19 or 10.21 widgets, while a reading of 10.2 indicates three digits of precision.) I wonder what this thingy provides on the accuracy/precision scale...
In the engineering/science world:
Accuracy: How close to the actual value (as per your note)
Precision: Spread over multiple measurements (ie repeatability)
Resolution: Smallest change which may be detected (not precision)
The wiki page covers it decently: Accuracy/Precision
#15
Senior Member
Join Date: Dec 2007
Location: San Jose, California
Posts: 3,504
Bikes: 2001 Tommasini Sintesi w/ Campagnolo Daytona 10 Speed
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 145 Post(s)
Likes: 0
Liked 35 Times
in
30 Posts
I got so excited I went out and just bought the Park tool for $48.41 delivered-
www.aawyeah.com/
40inutes later, I got the email confirming it was shipped!
www.aawyeah.com/
40inutes later, I got the email confirming it was shipped!
...before you use it.
=8-)
__________________
5000+ wheels built since 1984...
Disclaimer:
1. I do not claim to be an expert in bicycle mechanics despite my experience.
2. I like anyone will comment in other areas.
3. I do not own the preexisting concepts of DISH and ERD.
4. I will provide information as I always have to others that I believe will help them protect themselves from unscrupulous mechanics.
5. My all time favorite book is:
Kahane, Howard. Logic and Contemporary Rhetoric: The Use of Reason in Everyday Life
5000+ wheels built since 1984...
Disclaimer:
1. I do not claim to be an expert in bicycle mechanics despite my experience.
2. I like anyone will comment in other areas.
3. I do not own the preexisting concepts of DISH and ERD.
4. I will provide information as I always have to others that I believe will help them protect themselves from unscrupulous mechanics.
5. My all time favorite book is:
Kahane, Howard. Logic and Contemporary Rhetoric: The Use of Reason in Everyday Life
#16
Senior Member
Join Date: Dec 2007
Location: San Jose, California
Posts: 3,504
Bikes: 2001 Tommasini Sintesi w/ Campagnolo Daytona 10 Speed
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 145 Post(s)
Likes: 0
Liked 35 Times
in
30 Posts
For $295, they could at least let you enter the conversion factor for the current wheel's spokes, and then get kgf readings directly, without needing a spoke chart.
From the link:
The tool costs USD$295, and here is what you get:
1. A shock-proof, lockable, foam lined case with metal pin hinges.
2. 26 page Owner's Manual, with many wheelbuilding tips.
3. Laminated Spoke Tension Chart, for convenient conversion.
4. Spare battery.
5. A CD with PDF files of the manual and chart, and our instruction movie.
From the link:
The tool costs USD$295, and here is what you get:
1. A shock-proof, lockable, foam lined case with metal pin hinges.
2. 26 page Owner's Manual, with many wheelbuilding tips.
3. Laminated Spoke Tension Chart, for convenient conversion.
4. Spare battery.
5. A CD with PDF files of the manual and chart, and our instruction movie.
And have the converted result right there on the little LCD screen...
=8-)
__________________
5000+ wheels built since 1984...
Disclaimer:
1. I do not claim to be an expert in bicycle mechanics despite my experience.
2. I like anyone will comment in other areas.
3. I do not own the preexisting concepts of DISH and ERD.
4. I will provide information as I always have to others that I believe will help them protect themselves from unscrupulous mechanics.
5. My all time favorite book is:
Kahane, Howard. Logic and Contemporary Rhetoric: The Use of Reason in Everyday Life
5000+ wheels built since 1984...
Disclaimer:
1. I do not claim to be an expert in bicycle mechanics despite my experience.
2. I like anyone will comment in other areas.
3. I do not own the preexisting concepts of DISH and ERD.
4. I will provide information as I always have to others that I believe will help them protect themselves from unscrupulous mechanics.
5. My all time favorite book is:
Kahane, Howard. Logic and Contemporary Rhetoric: The Use of Reason in Everyday Life
#17
A little North of Hell
Thread Starter
Join Date: Mar 2006
Posts: 4,892
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 71 Post(s)
Likes: 0
Liked 4 Times
in
4 Posts
tensiometer
I got so excited I went out and just bought the Park tool for $48.41 delivered-
www.aawyeah.com/
40inutes later, I got the email confirming it was shipped!
www.aawyeah.com/
40inutes later, I got the email confirming it was shipped!
https://aebike.com/itemdetails.cfm?ca...+Daily+Deal%29
compare the $295 WF to the $249 FSA tensiometer.
#18
Senior Member
Join Date: Apr 2009
Location: New Rochelle, NY
Posts: 38,725
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
Mentioned: 140 Post(s)
Tagged: 1 Thread(s)
Quoted: 5793 Post(s)
Liked 2,584 Times
in
1,432 Posts
You know the spoke's gauge and your target tension. You look at the chart to find the corresponding scale value and decide on an acceptable tolerance. From there in you only need deal with the scale value, with no reason to convert to tension for each spoke.
__________________
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
#19
Senior Member
Join Date: Dec 2007
Location: San Jose, California
Posts: 3,504
Bikes: 2001 Tommasini Sintesi w/ Campagnolo Daytona 10 Speed
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 145 Post(s)
Likes: 0
Liked 35 Times
in
30 Posts
I'm starting to wonder how folks use tension meters. There's no need to refer to the chart more than once, before measuring, and no need to ever convert readings to kpf, except maybe once at the end.
You know the spoke's gauge and your target tension. You look at the chart to find the corresponding scale value and decide on an acceptable tolerance. From there in you only need deal with the scale value, with no reason to convert to tension for each spoke.
You know the spoke's gauge and your target tension. You look at the chart to find the corresponding scale value and decide on an acceptable tolerance. From there in you only need deal with the scale value, with no reason to convert to tension for each spoke.
=8-)
__________________
5000+ wheels built since 1984...
Disclaimer:
1. I do not claim to be an expert in bicycle mechanics despite my experience.
2. I like anyone will comment in other areas.
3. I do not own the preexisting concepts of DISH and ERD.
4. I will provide information as I always have to others that I believe will help them protect themselves from unscrupulous mechanics.
5. My all time favorite book is:
Kahane, Howard. Logic and Contemporary Rhetoric: The Use of Reason in Everyday Life
5000+ wheels built since 1984...
Disclaimer:
1. I do not claim to be an expert in bicycle mechanics despite my experience.
2. I like anyone will comment in other areas.
3. I do not own the preexisting concepts of DISH and ERD.
4. I will provide information as I always have to others that I believe will help them protect themselves from unscrupulous mechanics.
5. My all time favorite book is:
Kahane, Howard. Logic and Contemporary Rhetoric: The Use of Reason in Everyday Life
#20
Senior Member
Join Date: Nov 2009
Posts: 589
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
When I was at Trek, one of my duties was to keep the tensiometers calibrated for the wheel building department. We made a special test bed with a strain gauge to put a known amount of tension on a spoke and used that to calibrate the tensiometers. My lasting impression is an abiding dismay at how quickly tensiometers go out of calibration. When this duty threatened to become my full-time job, I was glad to pass it on to someone else.
Was any variation found in the spoke strength's.. to what degree did they vary?
#21
Roadkill
Join Date: Sep 2004
Location: East Tennessee
Posts: 858
Bikes: 2002 Lightspeed Classic; 2010 Pedalforce RS
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
When I was at Trek, one of my duties was to keep the tensiometers calibrated for the wheel building department. We made a special test bed with a strain gauge to put a known amount of tension on a spoke and used that to calibrate the tensiometers. My lasting impression is an abiding dismay at how quickly tensiometers go out of calibration. When this duty threatened to become my full-time job, I was glad to pass it on to someone else.
#22
Roadkill
Join Date: Sep 2004
Location: East Tennessee
Posts: 858
Bikes: 2002 Lightspeed Classic; 2010 Pedalforce RS
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
They use the tensionmeter to check final tension...they use tone to isolate "rogue" spokes not in line tension with with the rest as they are truing and tensioning.
=8-)
Sure, if you are building the exact same wheel all the time - you can establish a tone that matches. But if I bring 'em an unknown rim, hub, spokes, and specify the crossing...tone will not be the decider - tensionmeter will be.
The beauty of a tensionmeter is that it measures a deflection for a given length - regardless of gauge, length, crossings, etc.
=8-)
=8-)
Sure, if you are building the exact same wheel all the time - you can establish a tone that matches. But if I bring 'em an unknown rim, hub, spokes, and specify the crossing...tone will not be the decider - tensionmeter will be.
The beauty of a tensionmeter is that it measures a deflection for a given length - regardless of gauge, length, crossings, etc.
=8-)
On using a meter for the final tension, I think the tone method will get more even tension than using a meter if you aren't nearly tone deaf (assuming the spokes are all pretty much identical). But as you point out, you have to use the meter to establish what tone to listen for.
There are formulas to predict spoke tension from plucked spoke frequency, but these are very inaccurate and affected by the length of the butted section on spokes, spokes contact at the cross, nipple size & point of contact, etc, etc.
I don't quite understand your statement about a tensiometer measuring the deflection of the spoke. I agree with this, but the tension in the spoke is the thing we really want to know, and the conversion from deflection to tension does depend on spoke gauge.
I've wondered how good the tension meters are on bladed spokes. Tiny variations in size or shape could affect the deflection and the final tension deteremined from the chart. It seems that calibrating the meter would be particularly important for these.
I wonder how much we kid ourselves on the accuracy of our Park TM-1 meters and the accompanying chart? The engineer in me wants a calibration device.
#23
Senior Member
Join Date: Dec 2007
Location: San Jose, California
Posts: 3,504
Bikes: 2001 Tommasini Sintesi w/ Campagnolo Daytona 10 Speed
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 145 Post(s)
Likes: 0
Liked 35 Times
in
30 Posts
That is pretty much what I was trying to say.
On using a meter for the final tension, I think the tone method will get more even tension than using a meter if you aren't nearly tone deaf (assuming the spokes are all pretty much identical). But as you point out, you have to use the meter to establish what tone to listen for.
There are formulas to predict spoke tension from plucked spoke frequency, but these are very inaccurate and affected by the length of the butted section on spokes, spokes contact at the cross, nipple size & point of contact, etc, etc.
I don't quite understand your statement about a tensiometer measuring the deflection of the spoke. I agree with this, but the tension in the spoke is the thing we really want to know, and the conversion from deflection to tension does depend on spoke gauge.
I've wondered how good the tension meters are on bladed spokes. Tiny variations in size or shape could affect the deflection and the final tension deteremined from the chart. It seems that calibrating the meter would be particularly important for these.
I wonder how much we kid ourselves on the accuracy of our Park TM-1 meters and the accompanying chart? The engineer in me wants a calibration device.
On using a meter for the final tension, I think the tone method will get more even tension than using a meter if you aren't nearly tone deaf (assuming the spokes are all pretty much identical). But as you point out, you have to use the meter to establish what tone to listen for.
There are formulas to predict spoke tension from plucked spoke frequency, but these are very inaccurate and affected by the length of the butted section on spokes, spokes contact at the cross, nipple size & point of contact, etc, etc.
I don't quite understand your statement about a tensiometer measuring the deflection of the spoke. I agree with this, but the tension in the spoke is the thing we really want to know, and the conversion from deflection to tension does depend on spoke gauge.
I've wondered how good the tension meters are on bladed spokes. Tiny variations in size or shape could affect the deflection and the final tension deteremined from the chart. It seems that calibrating the meter would be particularly important for these.
I wonder how much we kid ourselves on the accuracy of our Park TM-1 meters and the accompanying chart? The engineer in me wants a calibration device.
Simplicity = Beauty
Deflection > Coversion = 1 Variable
Tone > Length + Number of Cross Touches + Gauge > Conversion = At Least 4 Variables (3 multiplied)
One is faster with the known...one is faster with the unknown.
Accuracy is not the goal - getting a "good" or "reasonable" estimate IS. Read my original post regarding using "fine" to " measure "rough". Once again, we almost never have "perfect" rims and spokes to work with. My meter for counting nipples has TOO much resolution for the job I have it do.
The Park TM-1 seems to do the job quite well - slightly better than the Wheelsmith which I always thought was a teeny bit short on resolution on the readout.
=8-)
__________________
5000+ wheels built since 1984...
Disclaimer:
1. I do not claim to be an expert in bicycle mechanics despite my experience.
2. I like anyone will comment in other areas.
3. I do not own the preexisting concepts of DISH and ERD.
4. I will provide information as I always have to others that I believe will help them protect themselves from unscrupulous mechanics.
5. My all time favorite book is:
Kahane, Howard. Logic and Contemporary Rhetoric: The Use of Reason in Everyday Life
5000+ wheels built since 1984...
Disclaimer:
1. I do not claim to be an expert in bicycle mechanics despite my experience.
2. I like anyone will comment in other areas.
3. I do not own the preexisting concepts of DISH and ERD.
4. I will provide information as I always have to others that I believe will help them protect themselves from unscrupulous mechanics.
5. My all time favorite book is:
Kahane, Howard. Logic and Contemporary Rhetoric: The Use of Reason in Everyday Life
Last edited by mrrabbit; 01-22-12 at 10:00 AM.
#24
Senior Member
Join Date: Sep 2011
Posts: 403
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
It might be fun to hang a banner on your bicycle that says "All of my spokes are tensioned to X <units>!". I bet the same number of people will actually CARE if the banner said "All of my spokes deflect Y <units>!", i.e. zero.
#25
Old fart
Join Date: Nov 2004
Location: Appleton WI
Posts: 24,790
Bikes: Several, mostly not name brands.
Mentioned: 153 Post(s)
Tagged: 0 Thread(s)
Quoted: 3590 Post(s)
Liked 3,401 Times
in
1,935 Posts
I'm sorry I can't recall specific numbers; this was over 25 years ago.