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  1. #1
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    Lightbulb 3D Printable Spoke Tension Meter

    If you have a 3D printer at home and want to dabble in wheel-building and/or maintenance, here is a 3D printable model of a spoke tension meter.

    3D Printable Spoke Tension Meter-20181114_111114.jpg

    It uses a very simplified parts list, all readily available from home improvement centers / hardware stores and places like Harbor Freight, and of course Amazon. there are only two 3D printed parts. The above pictured tool was printed in PETG with 3 perimeters and 4 bottom and 4 top layers, with 25% infill. It was my second printing and I would recommend 30 - 40% infill if you are printing this for yourself. All the printable STL files are located on Thingiverse as well as a STEP file for importing into a 3D CAD application, as well as an Autodesk Fusion 360 F3D file. The Thingiverse posting is located here: https://www.thingiverse.com/thing:3209607#. All files are free and licensed under CC BY-NC (Non-Commercial)

    The parts list includes:

    • 2 - M4 x 20 mm socket head cap screws
    • 1 - M4 x 10 mm socket head cap screw
    • 3 - M4 nylon insert lock nut
    • 1 - M3 x 12 mm socket head cap screw
    • 1 - M3 nylon insert lock nut
    • 1 - M2 x 10 mm socket head cap screw
    • 1 - M2 nut (must not be a locking nut)
    • 1 - 0.041" x 0.312" x 1.25" compression spring
    • 1 - 12.7 mm (1/2") dial indicator (I prefer digital for easier reading)
    • 1 - 624zz precision bearing
    • 1 - M4 nylon washer (sits between the two handle parts)


    Assembly is pretty straight forward and some instructions are available on the thingiverse file repository link listed above. Just a note about printing this at home; my slicer settings need a - 0.10 mm adjustment to get holes to print the correct size. The model is exactly true to size so if someone wanted to CNC this, no adjustments are needed. If you decide to print one for yourself please leave a comment on the Thingiverse link.

    This is a great tool for comparing spoke tensions from spoke to spoke. It would need to be checked against an existing known spoked wheels if you wanted to 'calibrate' this to get an exact tension. When I completed the tool above, all told I spent less than $25 USD, but most every part was sourced from China (AliExpress or Banggood) and Amazon.
    Last edited by WheresWaldo; 3 Weeks Ago at 03:34 AM.

  2. #2
    'brifter' is a lame word.
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    Nice, that would work very well.
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  3. #3
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    I updated the STL and source files yesterday to make them a bit better. If you downloaded them before that, make sure you have the version 6 files.

    There are now instructions for use. Since this is a derivative of the DT Swiss Tensiometer, the instructions are basically the same as using the DTS version. I am in the process of building a test jig, so I can at the very least approximate what deflection ~ what spoke tension. Right now I am just comparing it to a Park TM-1 tool and chart.

  4. #4
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    Well, I own that very same drop indicator; it cost about $40, and it's cheap. It has a display with rather poor contrast.

    You can buy a Park tensiometer for about $75. Using a drop indicator, which measures change in distance, would seem to be a backwards way of checking tension, requiring you to read a conversion sheet to get an actual tension reading. Between the time a 3-d printer takes, the cost of the supplies (and of the 3-d printer), plus whatever conversion you need to make to figure out what tension a certain displacement means, plus whatever you calibration you have to do, I don't see this being a viable alternative at all.

    For $35 more, you get a well-built metal, CALIBRATED tensiometer that gives you the actual tension off the scale. I can't see where futzing around with this kludge-job design would appeal to anybody other than guys who like to putter around in their shop all day.

    If you are just looking for something that will give you relative tensions between different spokes on a wheel, you already have the best device for that job; your ears.
    "L'enfer, c'est les autres"

  5. #5
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    Quote Originally Posted by No Time Toulouse View Post
    Well, I own that very same drop indicator; it cost about $40, and it's cheap. It has a display with rather poor contrast.

    You can buy a Park tensiometer for about $75. Using a drop indicator, which measures change in distance, would seem to be a backwards way of checking tension, requiring you to read a conversion sheet to get an actual tension reading. Between the time a 3-d printer takes, the cost of the supplies (and of the 3-d printer), plus whatever conversion you need to make to figure out what tension a certain displacement means, plus whatever you calibration you have to do, I don't see this being a viable alternative at all.

    For $35 more, you get a well-built metal, CALIBRATED tensiometer that gives you the actual tension off the scale. I can't see where futzing around with this kludge-job design would appeal to anybody other than guys who like to putter around in their shop all day.

    If you are just looking for something that will give you relative tensions between different spokes on a wheel, you already have the best device for that job; your ears.

    The Park doesn't do this.

    Last I knew the Park read an deflection value....that you then had to go to a conversion chart and read off the correct column for your specific spoke gauge/butting/profile. Maybe they've since changed that with a subsequent revision, but that is what the use of my TM-1 in my tool drawer I have from a decade back is like.

    You can see the included conversion spreadsheet in the product photos on Park's website:

    https://www.parktool.com/product/spo...ion-meter-tm-1

    User printable:

    https://www.parktool.com/assets/doc/...conv-table.pdf
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  6. #6
    'brifter' is a lame word.
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    Not to mention the Park doesn't stay calibrated very long. Doesn't really matter if you're just looking for consistent tension across a wheel, but for absolute tension they're not great.
    I work for some bike racers
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    and a bunch of skateboards

  7. #7
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    I also own the TM-1 and a clone of the old FSA tool, none of them read directly (even the DT Swiss uses charts, Wheelsmith too). All require a conversion chart of some kind or another. I also agree with @cxwrench, the Park tool loses calibration over time. It is good as a comparison device but not as an actual tension meter if you have owned it and used it regularly for a few years.

    Sound is the worst way to determine even spoke tension, but I gather you might be the person whose car doesn't have a speedometer and when you get your next speeding ticket you will tell the officer it was impossible for you to be speeding because the tire sound was the incorrect pitch, but I suppose that is your Hell to live in. Without a frequency measuring device ears are too imprecise to tell what frequency range is what. I spent a lot of time building golf clubs in a previous decade and frequency has to be very tightly controlled in order to be consistent, same is true for spoked wheels.

  8. #8
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    Of all the tensiometers out there, the Park Tools TM-1 is at the bottom of the list. Build quality, consistency, ease of use all make the Park TM-1 inferior. The FSA tool typically sells for around $275, the DT Swiss over $500, Wheel Fanatyk sells theirs for $215 - $340 depending on configuration.

    Chinese clones of the Park TM-1 can be found on eBay and AliExpress for $30 - 40 shipped. The Chinese clone of the DT Swiss sells for around $60 -70 from the same sources.

    In the grand scheme of things all of these will require recalibration at some point, unless you are simply a tool 'collector' and not a tool user. That is one reason I will be building a modified version of this calibration device (Jig description starts at 2:31):

  9. #9
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    Quote Originally Posted by WheresWaldo View Post
    I also own the TM-1 and a clone of the old FSA tool, none of them read directly (even the DT Swiss uses charts, Wheelsmith too). All require a conversion chart of some kind or another. I also agree with @cxwrench, the Park tool loses calibration over time. It is good as a comparison device but not as an actual tension meter if you have owned it and used it regularly for a few years.

    Sound is the worst way to determine even spoke tension, but I gather you might be the person whose car doesn't have a speedometer and when you get your next speeding ticket you will tell the officer it was impossible for you to be speeding because the tire sound was the incorrect pitch, but I suppose that is your Hell to live in. Without a frequency measuring device ears are too imprecise to tell what frequency range is what. I spent a lot of time building golf clubs in a previous decade and frequency has to be very tightly controlled in order to be consistent, same is true for spoked wheels.
    Hehe, that be dragons.



    Firstly, frequency analyzing/measuring devices don't help much, in this case. Spokes might share similar physics to a plucked string on a violin or perhaps a hammered piano string...but acoustically they don't share properties. Whereas a plucked violin E string has a predominant fundamental that you can listen and tune for easily (and a reliable set of overtone partials above it).....a bicycle spoke lacks the same--use a lab-grade oscilloscope on a spoke and it will see lots of "junk", as will any tuner-app on your phone (or similar stand-alone quartz digital tuner) will just jump back and forth unreliably (and somewhat chaotically). Which makes sense--spokes aren't made to be heard and have clear acoustic properties--but to be structural members....further in a wheel system you;re not just getting resonance/sound out of one spoke but many--making things more dirty.

    There was actual a thread about this very topic back almost a quarter-century ago in the dinosaur days of the internet, and Jobst Brandt himself actually weighed in: https://groups.google.com/forum/#!ms...w/Y6K8bfriZv0J


    As to the human ear...depends on your musician training, and how you go about applying it to wheels. The human ear can be very sensitive, especially in an application like this where a spectrum doesn't have an analytically-by-computer clear fundamental...and even without much training the human ear can perceive the common inconsistencies in spoke pitch quality as a result of imperfect rims/hubs (say +/-10kgf). Pitch resolution (as applied to spokes) is helped because you're talking about middling pitch ranges, not anything to absurdly low. My ears are good down to +/-0.5 equal tempered cents pitch differential (all those years of music school, what can I say), which for reference is <1% of the difference between two adjacent keys on a piano.

    None of this is to actually advocate ears-only wheel building, mind you. Just to address some semi-tangential issues a bit

    (Note, I've never actually tried to challenge a policeman's radar gun based on ambient cabin noise levels)
    Last edited by Marc; 3 Weeks Ago at 02:06 PM.
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  10. #10
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    Alas, years of working in industries that are plagued by noise and my ears are not that sensitive, even if they were I would still need a chart to convert the heard frequency to a given spoke tension.

    I am very familiar with Jobst Brandt's work and his theories on wheel building.

    In the end, I built a tool. A tool that only has one purpose, to make building a wheel a bit easier and more repeatable. I am sharing that with anyone that wants to try it out for themselves, enough said.

  11. #11
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    Thanks for this thread, if for no other reason than it's a good reminder that I really need to replace my old tm-1.

  12. #12
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    Apparently I'm not able to post a picture of an instrument I built a few years ago. It's just a simple fixture to hold a dial indicator on a spoke, and a weight to bend the spoke. I calculated the the deflection/tension curve using the cable tension and beam equations, so I didn't need to calibrate it. The downside is it only works with the wheel held horizontally. It's definitely not a professional tool but it's just as accurate anything you can buy for a reasonable price. IT's hard to use but it works for me for the few times I need to check tension.

    em
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    Last edited by eddie m; 3 Weeks Ago at 10:02 AM.

  13. #13
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    @eddie m
    Get a free account on a site like IMGUR. you can upload pictures there and then they will create links that you can copy and paste into sites like this. I am curious to see your fixture.

  14. #14
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    There are two other tensiometers that can be 3D printed at home. Both are derivatives of the Jobst Brandt design.

    https://www.thingiverse.com/thing:2810089/
    https://www.thingiverse.com/thing:3220573/

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