Thoughts on a Bicycle Spoke Tension Meter

Location
Loch side.
Thoughts?

Firstly, what problem are you trying to solve? Broken spokes? Broken spokes have nothing to do with spoke tension.

Secondly, what role will a tension meter play in your wheel repair? Wheel tension isn't something that's universal. Different wheels require different tensions and how will you know what tension to apply?

Thirdly, the claims by the tension meter company are erroneous:

"Tight and uniform spoke tension is the key to a strong and long-lasting wheel, and this innovative design takes the guess work out of achieving that perfect spoke tension!"

The faulty claim is above. A true wheel does not have even tension and conversely, a wheel with even tension is not true.

Plenty has been written on this forum on spoke breakage. Search for "metal fatigue" in conjunction with "spokes" and "stress relieving".
 

rogerzilla

Legendary Member
The correct spoke tension is basically the highest that won't cause the wheel to pringle elastically or cause spoke pull-through or flange cracking. With a good quality forged hub shell and a very stiff, eyeletted rim, the limiting factor may actually be how hard it is to turn the spoke nipples. I found this with DT XR 4.1 MTB rims - they are enormously stiff and you'll split the spoke nipples first. I rode one of those wheels, which had a ceramic rim, for 9 years' commuting and the only maintenance it needed was a new set of hub cartridge bearings.

I build wheels very tight and have never had spoke pull-through on any rim. I did have a LH flange failure but that was on a non-forged* Goldtec hub after three winters, and I'm sure road salt helped it along. The drive side flange was filthy with chain oil and showed no signs of cracking.

*CNC hub shells are not a selling point; it just means the manufacturer is too small to invest in forging presses
 
Location
Loch side.
I build wheels very tight and have never had spoke pull-through on any rim. I did have a LH flange failure but that was on a non-forged* Goldtec hub after three winters, and I'm sure road salt helped it along. The drive side flange was filthy with chain oil and showed no signs of cracking.
It i s a fallacy that spokes pull through the rim from tension. They pull through because the rim failed. That failure is due to metal fatigue. It is virtually impossible to have a spoke pull out of a new aluminium rim whilst building, but after prolonged use, it will come out spontaneously without any increase in tension.
 

rogerzilla

Legendary Member
Sorry, I should have clarified it as "eventual" spoke pull-through. It would have to be a spectacularly rubbish rim for spokes to pull through during the build process.

A lot of rims show powdery corrosion around stainless eyelets after a while (especially visible on black ones) but I've never personally seen this progress to actual pull-through. It may just be that the eyelet frets at the aluminium and prevents passivation.
 

silva

Well-Known Member
Location
Belgium
Sorry, I should have clarified it as "eventual" spoke pull-through. It would have to be a spectacularly rubbish rim for spokes to pull through during the build process.

A lot of rims show powdery corrosion around stainless eyelets after a while (especially visible on black ones) but I've never personally seen this progress to actual pull-through. It may just be that the eyelet frets at the aluminium and prevents passivation.
That kinda corrosion is named "galvanic" corrosion. Metals have a so called degree of nobility, where a more "noble" metal corrodes a less noble metal, on condition of the presence of an elektrically conducting medium (electrolysis). The least noble metal gets dissolved, hence the powder.
The degree of the corrosion depends on the electrical current intensity and thus on the individual masses of the individual metals. For ex, the case of a stainless eyelet in an aluminium rim, the aluminiums mass is much bigger than the stainless steel mass, which makes the corrosion least worse.
But if you have a long stainless bolt through a small aluminium block, the corrosion is worst.
I had this latter problem with my new bicycle, at some point the stud of the bicycle required retensions and this became worser and worser, upto the point that I had to retension several times in an hour in the case of a market with alot stops. In the end, I decided to dismount it to find any explanation, and the holes of the two stainless steel bolts were filled with white powder. On the bolts and counternuts I saw A2-70.
The bicycles producent apparently wasn't aware of this galvanic corrosion, chosed stainless steel in an attempt to do good, but instead did worse.
I solved it by replacing the stainless bolts with normal steel bolts, and kept these well oiled to avoid normal corrosion. But since, the stud has quite some wiggling room. The stainless steel corroded the inbetween block but also the frame holes. Hard to solve.
 
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