[MTB maintenance] Updated conversion diagram for my Chinese spoke tension meter

[@pathtononduality]

I just ordered a Ztto TC-1 tension meter that reportedly has been calibrated and tested to an accuracy of +/− 10%. Let's say I take a reading on a hex key with my new meter and document it. Do you think I could maintain the original accuracy of the meter by calibrating it with the same hex key?

[@MindDesignFactory]

Yes for a limited period of time. While the master hex key shows the same reading before you use the meter, your meter can be considered to keep the original "accuracy". But once it starts to show a smaller master hex key reading, it implies that the spring of your meter has started to deteriorate and no longer keeps its original accuracy. To a certain extent, however, you can adjust the preload of the meter's spring so that it shows the original master hex key reading to compensate for the meter spring deterioration. For home use only, you can keep your meter to be accurate enough by making your own master hex key and using it to check your meter each time you use your meter. Just keep in mind, though, that there is a reason for why those Chinese tension meters are cheap. Thanks for watching!

[@atexnik]

This ZTTO meter is rather bad. It uses thrust bearings instead of roller bearing as other similar products do, and as a result there's a significant drag in the pivot. You can remove the spring to check how smoothly the lower lever moves under its own weight. Even with the bearing bolt tightened just enough to take up the play in the bearings, it introduces quite a bit of friction, which immediately distorts reading.

[@MindDesignFactory]

I got your point. But unless you make a living by building wheels, that drag you mention won’t make any severe difference on readings when dealing with 90 or more kgf of spoke tension. Certainly you FEEL the lever dragged due to the use of bushings instead of roller bearings, but it will be nullified by the tension force applied to them.

[@atexnik]

​In my case rotating the bolt just a tiny fraction affects the reading significantly, especially on carbon spokes @@MindDesignFactory

[@MindDesignFactory]

Hi, I have just looked into my own tension meter. First, there is no noticeable play at the bearing of the pivot. Secondly, I can't feel any drag there and the lever moves quite smoothly with or without the spring force. There seems to be something very wrong with your meter. Couldn't you request a replacement from your seller?

[@atexnik]

​​No, there's nothing wrong with mine, this is by design. Also, the play is removed by the tension bolt, it is not a sealed bearing, but a thrust bearing. I don't know what is smooth for you, but for me, having fluctuation ±15 kg depending on how much you tension the bolt, is a no go in context of a "precision" instrument. Hence, currently I am working on my own precision meter with linear bearing, and this one is going to bin later.​@@MindDesignFactory

[@atexnik]

​@@MindDesignFactorythere's another version of these cheap Chinese clones, it is called Toopre, it has roller bearing as on original DT Swiss tensio. That one is much better in terms of accuracy.