How to Use the Park Tool TM-1 Tension Meter & Wheel Tension App

In this video, we will walk through the use
of the WTA Wheel Tension App for the Park Tool TM-1 Tension meter. The WTA is an excellent system to help understand spoke tension as they relate to one another. It’s very useful in diagnosing when a wheel has a problem. It helps you document a wheel that has been pulled correctly tight. It also helps you teach new mechanics the concept of spoke tension. We’re going to measure the spoke tension,
we’re going to document it on the computer, and then we’re going to look at the charts
and statistics that tell us what’s going on with the dynamics of the spoke tension. We will need the TM-1 Tension Meter, a caliper, a spoke wrench, a marker,
a computer with internet access, truing stand to hold the wheel, and we’re
ready to go. Open a web browser and go to for the wheel tension app. Here, begin with wheel settings.
the material drop down box has five choices. Our material choices are represented here.
Steel can either be a stainless steel or a carbon steel. Steel is always at least somewhat magnetic, so if in doubt, use a magnet
and see if it holds gently or firmly. Definitely a steel spoke. An aluminum spoke will be larger –
more material – it is not magnetic at all. Spinergy PBO is a proprietary
fiber material unique to Spinergy. Titanium spoke has no magnetic properties at all –
It’ll be much smaller than the aluminums and Mavic carbon fiber R2R is a unique
proprietary spoke to Mavic. For spoke materials other than steel,
select the appropriate spoke type and dimensions from the drop-down menu. The WTA will then display the corresponding conversion table. These conversion tables can also be found on the printed chart that comes with the TM-1. The WTA is limited to these
options for non-steel spokes. For steel spokes, the WTA can generate conversion tables for any size round or bladed spoke. In the round spoke, we want to measure in
the middle of the spoke, not at the very ends. There can be butted spokes that are
thicker at the end and thinner in the middle. Here, we want to measure where the TM-1
would be deflecting. Enter the diameter rounded
to the closest tenth of a millimeter. In the blade shape, we need two measurements:
the thickness of the spoke and the width of the blade. Use a caliper to measure the thin section of spoke
rounded to the closest tenth of a millimeter. Take a measurement of the width – also round
it to the closest tenth of a millimeter. We can hit update and this produces a TM-1 conversion table that is unique
to the spoke diameters that we have entered. The TM-1 conversion table produced by the WTA gives us a range of tension readings. Each has a corresponding
spoke tension in kilograms force – for example, a spoke with a reading of 9
has a tension pull of 66 kg. This is unique to the 1mm by 2.2mm bladed spoke. On a wheel, it is the rim that determines the
spoke tension, not the spoke itself. Recommendations for spoke tension can be found
at the instructions page of the WTA. Here we’ll find front and rear kilogram force
recommendations for several different brands. Always consult the manufacturer for the most
up-to-date information. If you’re looking for a rough idea, you would
stop here. Check the tension chart on the WTA and see
approximately where you want to be on the recommendation you’re looking for. On this wheel, we’re trying not to exceed 120 kg. I look on our chart – readings of 15 are about 117 kg so we’re trying not to see much more than
15 on the average. So we’ll grab a handful of spokes here.
Fourteen, Fifteen. We’re between 14 and 15 – we’ll do 14 and a half.
Do not try and be more precise than half digits. Here, 14 and a half again. So I don’t think we’re beyond the recommendation that we’re looking for. Depending on if you’re high or low
from the target that you’ve selected, you would change the spoke tension
on the entire wheel. The WTA also offers an
optional wheel tension balance feature. What this does is it helps us even the tension. On the right side of the wheel, we’re going to check and document and measure all the right side spokes and then adjust them so they are
relatively close to the same tension. The left side spokes – we’ll do the same. This gives us a more complete
picture of spoke tension, it lets us document the work that we’ve done, and it’s also useful in diagnosing wheel issues and problems. To use the wheel tension balance feature,
scroll down to wheel tension balancing. Here, select the number of left side spokes
and then the number of right side spokes. In our example, we have a 20 spoke wheel – 10 per side. We get, then, 10 entry fields on the left
and 10 entry fields on the right. For easy reference, write on the rim braking surface the numbered spoke. This can be wiped off later
with almost any kind of solvent. So here from the valve as a constant reference, we mark one, two, three, four all the way
around – only right side spokes. On the other side, we begin at the valve again,
but now we’re going to the left – one, two, three, four this is done so that one and
one on the left and right side stay together – three and three, four and four – all the
way around the rim. From here, begin at the first spoke. We take a reading and we can
enter it in the entry field at the WTA. Use the Tab key to move to the next field. Using the Enter key will refresh the page
each time and slow your work. At the end, then, hit enter. The WTA will convert
all your readings to a kilogram force and produce a radar chart of the relative tensions. Next, proceed to the right side, and again
use the Tab key and hit Enter or update and we get the left and right side tensions –
kilogram force for each one and we get a radar chart that’s
representative of the tension of the wheel. The dots or data points that are closer to the center are lower in tension it’s tighter and tighter further away from the center. As the mouse hovers around, it will give you
the spoke number and the tension of that spoke. It is normal to see these as not a perfect
circle – some anomalies are possible it does not mean it’s an unusable wheel. The wheel tension balancing page
also contains a variance. This is a plus or minus percentage amount that
will help the spreadsheet call out spokes that are outside the limit of the average. On this wheel, we have check marks in every box – they are all within plus or minus 20,
which will produce really good wheels. If we pick 10 percent, we can see here spokes that are outside – we have spoke three, five, and seven. Here, we do have a couple as well – spoke
five and spoke eight. So, understand it may take more time – and
possibly an upcharge if you’re a retailer – to produce tighter and tighter tolerances. The WTA also gives basic stats for the wheel. Left side and right side will have numbers
for average tension, standard deviation, the limits that you have selected in your variance, and also the TM-1 readings that are equal to the limits in the variance. Check the average spoke tension against your desired kgf target and adjust the overall wheel tension accordingly. For more on adjusting overall tension visit wheel and rim service in the repair help section of It’s common to see the right side on a rear
wheel be tighter than the left side. On a disc front wheel, however, the left side tension will be higher due to the spacing from the rotor disc. This 20-hole rear wheel turned out pretty nice.
Let’s have a look at a different wheel. This wheel is a 32-hole front
thru axle mountain bike wheel. We have decent tension all the way across the left side. We have pretty good tension across the right side. We can see our diagram doesn’t look perfect, yet we’re still within our plus or minus 20 percent. If we change here to plus or minus 15 percent, you can see we’re actually starting to come
out a little bit on the right side. If we continue to plus or minus 10 percent, more spokes are showing to be out of that tolerance. Let’s use plus or minus 10 percent, which brings out the left side number 8 and number 9 as problem spokes. 8 being on the looser side, 9 on the tight side. Tension balance is a process of sharing the
load equally amongst the spokes. The right side spokes will be set to be even
tension to other right side spokes The left side spokes will be set to be fairly
even tension between left side spokes. Remember – when we true a wheel, we tend to
tighten tighten tighten to correct problems. It’s a habit, sometimes, to always go to
one spoke to fix a problem when we could be going to several different options. That tends to create imbalances in tension
– even if the wheel is spinning nice and true. This wheel is spinning very nicely – but we saw on number eight and nine on the left side we have an issue. Number eight being relatively low,
number nine being relatively tight. This spoke is eight and spoke is nine. They both share a common
zone of influence in the middle. We’re going to set our caliper to that middle spoke. Eight is here and nine is here.
We get our caliper very very close a very narrow gap, even pulling
the other caliper out of the way. Here, we’re gonna tighten the loose spoke
– possibly a quarter turn. This gap has closed up. We’re now going to loosen until we get the same appearance of that same gap. The reason is this will help keep the true in this area. Lastly, we double check our numbers. 24 here 24. So we’ve come to much closer tension
on these two spokes. We enter our new data and see where it puts us. We enter our corrections – readings of 24
for both we hit enter and these two are no longer a problem. We would proceed to spokes 9 and 10 on the right side
and make our corrections there. Below the wheel stats is the print wheel set data. This is an option for you to enter a customer’s name, should they have one, the rim if we know the rim,
the type of spoke if we know it, the hub if we know it, we could enter any
notes that we would like, then we would hit save. What happens is the WTA
creates a new and unique URL. This is something that can be emailed to yourself,
you can email it to a customer, but please note the Park Tool Company
cannot get any lost URLs. It’s the responsibility of the user to track their data. Another option is save as duplicate. What this does is maintains all the same settings
and all the same text. If you’re repeating the same type of wheel
again and again, you can simply come down and enter new readings. A third option is the print option,
and here of course you can save as a PDF and this can be emailed without changes possible. If you do email the URL to someone, do realize they are able to put in different numbers as they choose. The WTA is also useful when diagnosing and documenting wheel problems. Here, we have a 32 hole rear wheel.
It shows pretty decent tension, except we can see spoke 16 on the right side is quite low and spoke 1 on the left side is also quite low. Here is our spoke number 1 on the left side.
This is spoke 16 but from the right side. Here, we can move the rim back and forth
and we can see the problem. This is called a flat spot. If these two spokes were overly tight, they would pull the rim toward the hub and create this problem – but we’ve seen and documented that these two spokes are actually quite loose relative to the rest of the wheel. What’s occurred is an impact has happened here
that has bent the metal. We really can’t loosen these spokes anymore to return the rim to its shape. The metal has been bent. There’s nothing really going to get it back
to where it used to be. The WTA is showing the problem that we’ve
seen on the wheel. This can be used to help explain to our customer or to our friend why they really need to look at a new rim. Here is a different wheel. This is a 32 hole wheel that has had a
lateral impact or sideways impact and what we notice here is that we have a severe crossing of fthe right and left side tension lines. It looks fairly normal until you come around
to spokes 14 and 13 here. So what’s happened is through a sideways or
lateral impact, the rim has been bent. The previous user has attempted to tighten the left side and loosen the right side to get it to straighten up, but there is no way this wheel
is going to maintain much of a true. Here, an indication again – the rim material is bent. It’d be very difficult to keep this thing true for very long. By taking the time to measure and document and record on the Wheel Tension App, you can
produce better wheels. You’ll have a better understanding of the
dynamics of spoke tension and be able to diagnose
when the wheel just isn’t working. So, find the WTA at We would like to thank Chip Howat of Howat
Associates for his assistance in the creation of the
TM-1 tables and spreadsheets. Thank you.

82 thoughts on “How to Use the Park Tool TM-1 Tension Meter & Wheel Tension App

  1. I bought the TM-1 tensioner because it's a park tool and didn't even know how to use it. But now i do. Thanks for this video and for the great app!

  2. Just purchased a TM-1, very glad I found this youtube video. The online Park Tools URL app is an excellent free resource, customers can hold bike shops to accountability. This is a simple java script, there's alot of s/w that can d/l this script, then you can convert it into android through an app porting utility. If you're working on the same rim all the time, perform the spec once, print it out and just use excel with a simple multiplication formula. I'll be fabricating my own truing stand with dial gauges instead of eyeballing the gap with typical store bought units. If Park's TS2.2 was at least 35% cheaper I'd buy it, however my higher precision DYI stand will be under $150 all in (3 dial gauges, angle steel, hardware, 2 hrs labor).

  3. After you guys set your brain buckets down for the day, I'd like buy you all a round of beers. Great product line. Keep 'em coming!

  4. Amazing tool, thank you so much ParkTool. I've use it for first time on by race bikes rear wheel. The spokes were creaking and loosed its tension. Its fanastic what the tool did to the wheel. Now with your tool i made the wheel like its just came out from the factory. Before i used only spoke wrench, testing the spokes with the fingers. As a result spokes were never perfect. But now they are fine tuned. Thank you!

  5. I could probably do with this tool!
    I tried to rebuild a wheel once I didn't cross the spokes enough and they all stuck out from the inside of the rim so I just cut the spokes off the result was funny, I was sitting on the handle bars like et while a friend was riding and the front wheel whent down a little dip and the wheel collapsed!

  6. Okay few questions im sort of confused on. Why does 1 of the wheels have obvious tension differences from the left and right, as in the left side is much more and the right side is much less, is that normal? And How do i know the tension for my wheels when there not on that chart, i have Alexrims ATD470. Thanks!

  7. at 2:50 what is that tool called that he's using to messure the spike diameter?

    Every video I've seen that gives a list of tools one should have all neglect to mention that one and I need to know what to type into search fields.

  8. That is spectacular! Thanks. Now I just have to buy the wheel truing stand and I am less anxious about spending the money.

  9. So should I try to bring my wheel into the 5-10% variance and then true it from there? I'm speaking on behalf of old rims and new rims.

  10. Fascinating Tutorial. This sort of app really brings cycle mechanics to the 21st century.

  11. Hey Calvin, How do I deal with different size spokes? I've got a disc brake road bike with 1.05 x 2.85 bladed spokes on the R front and L rear and 1.25 x 3.0 on the L front and R rear. The stronger on the rear drive or front disc. These are both 24 spoke DT Swiss R23 DB Spline wheels. The other curious thing is that the weak sides were barely registering on the TM-1. The front weak side was in the 5 range on the TM-1.

  12. HI ! Will you please give us an advice as to what spoke tension to consider between the tension when the tire is removed from the wheel and tension when tire is on the wheel and inflated? I mean I measured tension of an ultegra wheel without tire and got 19 on the scale of parktool tension meter , but when I measured without the tire inflated, it returned 16 on the scale. Which of two should we consider when checking against manufacturer tension recommendation? Thank you!

  13. Hi – I have the TM-1, and the app on my iPhone and iPad. My business and associated admin (I would like to use the customer service charting) is conducted on a Mac – Are there any plans to make the app available for Mac…. Many thanks SB

  14. this is one of the most informative videos on fixing wheel spoke issues ive ever watched! i should watch more park tool videos..

  15. 17:23 this is what I had to fix today. Fun fun fun! Without a doubt, it has a flat spot. I told the customer this, didn't care. I could of sold a new wheel if I used this app and showed it to him.
    What else I see, is that I can cover my butt if I run into this again in the future If I recommend a new rim, and the customer don't care, and wants a free new rim later after it's trash because he didn't care the first time, and wants to claim it was my fault.
    Liability is job one in any successful business. These days it's not enough if you tell someone they need this or that. You need to show them why, or they think you're just trying to make a few extra bucks off them. Then they come back for the told ya so.

  16. You are professional bike maintainer 🙂 spoke tension metering and computer aided problem solving. I am a poor man, I just grip spokes to feel with hand. You have a point in truing a bent rim that it is not lasting true long. Maybe a poor man has to true it many times to save a wheel, i hope.

  17. this tool can be calibrated ? for how long it remains calibrated considering it must be accurate every time when i use it ?

  18. Great for wheels 24 " and larger, however I do a lot of 16" and 20 "wheels for tricycles and recumbent bicycles,and electric wheels with large hub motors. I need a tool for smaller wheels and spokes of 63mm.
    Any help would be appreciated.

  19. A cheap and easy way to do the same, is to bang the spoke lightly with a metal tool, and then listen! If the tension is the same for all spokes, and the wheel is correctly sat up with no going up and down, or to the side – it will give the same sound.

  20. Hi, could you please advise whether is normal to have some spokes on non-drive side with the scale measuring 0 on Parktool TM1. I just bought a MAVIC KSYRIUM ELITE wheelset and with tire inflated some spokes shows 0 on the scale. On the drive side the tension seems to have the manufacturer's recommended tension. Thank you !

  21. Just picked up some cheap wheels from the far east to mount some homemade ice tires. They are cheap, aluminum 26"ers and I can't find a manufacturer to determine the appropriate max spoke tension. I don't want to break them, but I need a benchmark to aim for when tensioning up the spokes. What benchmark should I use?

  22. I've had the TM-1 for a couple years and have found it useful in building wheels. When I built my first road bike wheel, I measured the tension in all the spokes, calculated the mean tension for each side (it was a rear wheel) then figured out the percentage difference from the mean for each spoke… it was an interesting exercise, but it took ages. A few days ago I became aware of the Wheel Tension App and my head practically exploded! Yesterday I finished my first front wheel and did the same analysis in a fraction of the time, and have a slick print-out to document it. FWIW, it's good within 10%… not bad for a newbie!
    This video was very clear, easy to understand and helpful. Park Tools has put together an amazingly useful site for the do-it-yourselfer.

  23. 13:26
    The problem is that if you correct tension of a “bad” spoke, you have to recheck all other spokes since their tension is changed too. All the recordings in a form will be different.

  24. Great Video! I am still slightly confused as to the tension on one side of the rim vs the other. why would the load not be evenly distributed between left and right side? Thanks for these videos !!!

  25. Excellent explanation, thankyou guys from Park Tool, that helped me understanding the theory of truing rims, more than the practical stuff I do on mine, I'd like to have this guy truing my wheels! Nice mustache hahaha

  26. When measuring spoke tension, should you have a tire installed and inflated to the proper pressure or just the wheel without the tire?

  27. Nice to see a tool like that, would not be usefull in my company though, its just to slow to process all oure bikes like that. We just do it by feeling and touch. We got around 3500 bikes. Maintaing around 10 to 15 a day for yearly maintenance then repairs in between it is just not feasable. And specialised maintenance for atb and racing bikes is too far in between to even consider doing that. It would simple get too expensive to buy the tool and for the customer as well due to the ammount of working hours input.

  28. 5:38. You can't just change the spoke tension like half a turn for the entire wheel to get it in range. You WILL put your wheel out of true. It's much more complex than that.
    You might think that doing this won't do anything to the trueness of your wheel but it will.

    There's not only lateral trueness (left and right), but radial trueness (ie. if the wheel has a bulge in it). You also have to consider that the hubs on bike wheels are not perfectly centered, especially on bikes with disc brakes and back wheels (because of the cassette).

    So if you loosen all your spokes even 1/4 of a turn, you will warp your wheel.

  29. ha! you just answered all my questions and gave away the last secrets of wheel truing.
    that overall tension metric has been gnawing at me for years.
    any idiotic comments in the thread are due to the demystification of witchcraft.

  30. In case of ALUMINUM spokes, are the all made from same type of alloy? Assuming that I have 2.54mm type1 alloy reading is showing me 25. And I'm making another wheel with 2.54mm type2 alloy, again reading is showing me 25 but one can be stiffer from the other right? Or It's so minimum differences that only people in Mavic,DT… are taking care about?

  31. Why is it that you have different tension ranges for the left and right side? (shown in the app as the blue line being wider than the yellow line). Shouldn't both sides of the wheel, left and right, have the same tension?

  32. How should recommended spoke tension be interpreted for the rear wheel, where the tension between the spokes on the two sides can be substantial?

  33. thanks a lot, I like, learn how to do by your Video, it very helpful !

  34. Very nice video for whoever love good taking care of wheel. Specially who purchase expensive wheel and ride passionately. Wheels condition is most crucial part of bike mechanics,

  35. I bought this tool only because this nice tutorial video. A nice tutorial make to us easier to understand how to use a tool and avoid a lot of headache! Thanks!

  36. Make it an 'App store' application instead of a 'Web based' app and i'll buy the tool. I don't want a tool that depends on my 'internet availability'.

  37. After mounting a tire onto the wheel the tension decreases. So the spoke tension should be measured with a mounted tire to achieve the specified tension, am I right?
    Thanks for the great video!

  38. I used it to even tension out on each side o my rear wheel (each side different even tension for all side spokes). Now my wheel wobbles and is not true. WTF?

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