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Old 09-16-10, 11:51 PM   #1
Aquakitty
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So why exactly did I buy this tensionmeter?

I just built my first wheel, after a couple hiccups (namely, accidentally dishing the wrong direction, oops!) its looking good..
After reading a few online sources, many seemed to say making do without truing stands and dishing tools was pretty easy, but a tensionmeter was a good investment. So, I bought one to try out.
However, it is not clear what I am supposed to do with this tensionmeter... I can measure the spoke tension, but how is that helpful as I have dished the wheel and if it was too tight how could I even fix it without throwing the wheel off? I mean given a spoke size once the wheel is dished doesn't it just require that tension? If I add up my wheels and find the tension is too high what should I do?

Thanks..
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Old 09-16-10, 11:53 PM   #2
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If the tension is too high you need to back off all the spokes by enough to bring the tension within specs... running too high a tension can cause rim damage and spoke breakage.
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Old 09-17-10, 12:04 AM   #3
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My thumb doesn't like that answer ... but ok, so measure all around do the math if too high back off a bit?
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Old 09-17-10, 12:05 AM   #4
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What kind of wheels are you building ?
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Old 09-17-10, 03:10 AM   #5
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What kind of wheels are you building ?
26" MTB
Brave Dlux rims w/ Sapim DB spokes 32 H 3x pattern
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Old 09-17-10, 03:40 AM   #6
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Originally Posted by Aquakitty View Post
I just built my first wheel, ... many seemed to say .. a tensionmeter was a good investment. So, I bought one to try out.
However, it is not clear what I am supposed to do with this tensionmeter... I can measure the spoke tension, but how is that helpful ...?
Because tight tends to mean different things for different people, now you can put a number on it. W/o one you'd have to rely on luck, wild approximations, or whatever experience you've managed to collect so far.

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..I have dished the wheel and if it was too tight how could I even fix it without throwing the wheel off?.... If I add up my wheels and find the tension is too high what should I do?
One way or another, wheels are balanced structures. If you have to lower one side, then you lower the other too, to maintain that balance.

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....given a spoke size once the wheel is dished doesn't it just require that tension?
If you're able to find it, what you start with is the tension recommendation for the rim, then you take the spokes up to that. For a dished wheel the slack side will be whatever geometry dictates.
You can still use the tensiometer to get the spokes for each side as evenly tensioned as possible.
Any wheel will eventually be a compromise between, true, round and evenly tensioned. Dish has to be met too (when applicable), but is less of an issue, as the opposing force of the spokes makes it fairly easy to adjust.
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Old 09-17-10, 08:29 AM   #7
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Have a look at the explanations and radial graphs here: http://www.parktool.com/repair/printhowto.asp?id=173. The visual approach certainly helped me. A tension meter will help you get into the correct tension range for your rim and will help you build a wheel with balanced tension. These are key factors in making sure your wheel will last without prematurely going out of true.
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Old 09-17-10, 11:18 AM   #8
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I had to reread dabac's comments because after reading it, I thought I wrote it! Not that it matters, but I agree with dabac 100%.

Adding or repeating just a couple of things.

You try to get the wheel both true (side to side wobble) and round (up and down bumps) and the correct spoke tension but eventually it becomes a compromise. The more often you keep the wheel perfectly true, the fewer holes, bumps, rough pavement you go over or in, the stronger the wheels are - both rim design, # of spokes, spoke pattern, and with correct tire pressure for your body weight which is low, not the maximum!, the longer the wheel will stay true.

Front wheel: spoke tension should be equal on both sides, 100% perfect dishing is not critically important though it has to be close.

Rear wheel: Adjust the cassette side to obtain the correct dish for your bike and wheel for true and then check your spoke tension. If it's correct, your done. If not, you need to adjust the spokes to get the correct tension on both sides of the wheel by either raising or lowering the spoke tension and either on one side, each side, or both sides checking for true and dish.
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Old 09-17-10, 11:26 AM   #9
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Originally Posted by Aquakitty View Post
... I can measure the spoke tension, but how is that helpful as I have dished the wheel and if it was too tight how could I even fix it without throwing the wheel off? I mean given a spoke size once the wheel is dished doesn't it just require that tension? If I add up my wheels and find the tension is too high what should I do?

Thanks..
The bolded part is the key to where you made your mistake. You're trying to use the tensionmeter as a last check tool instead of the proper method of using it during the whole tensioning and trueing process. In any wheel build we need to bring the wheel to tension and true in a series of steps working up to the final product. Along the way we stress relieve the spokes and retrue as needed and try to work in an overall balance in the spoke tensions as we go. You should have been using the meter during at least the last two or three times around the wheel to work in the balance in conjunction with the true. Those of us that do it by feel or ear do this automatically by feeling or tapping the spokes during the intermediate stages. In your case you've got the meter and should be using it. Otherwise you're right. Using the meter at the end of the process when you're all done turns it from a building tool into an inspection tool. You're only getting half your money's worth by using it that way.
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Old 09-17-10, 01:58 PM   #10
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One of the problems that I have with wheel building is that I don't have enough tension for fear of pulling a spoke nipple through a rim. I now true, then tension, then re-true, then check tension again. and repeat again making small adjustments. Yes true and tension is a compromise.
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Old 09-17-10, 03:39 PM   #11
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One of the problems that I have with wheel building is that I don't have enough tension for fear of pulling a spoke nipple through a rim. I now true, then tension, then re-true, then check tension again. and repeat again making small adjustments. Yes true and tension is a compromise.
If you pull a spoke thru the rim you have bought a junk rim. The rim should go out of true when stress relieving when the tension is too high.
Most of my builds are with Mavic rims and they reccomend 110kg max. I may go over or under depending on the expected load.
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Old 09-17-10, 03:59 PM   #12
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If you do need to reduce tension without throwing off the true/round (by much), back off EVERY spoke by 1/4 turn. Repeat until you achieve the desired tension, then do your de-stressing and truing.
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Old 09-17-10, 04:36 PM   #13
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The "s" is working on the keyboard so it isn't the keyboard's fault.
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Old 09-17-10, 04:47 PM   #14
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Thanks for all the posts, this has made it a lot more clear to me.

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Originally Posted by BCRider View Post
The bolded part is the key to where you made your mistake.

Well have been using it the entire time, just wasn't sure what to do with the info.. I have been keeping the spokes at similar tension, or trying to.

One more question, these are fairly heavy duty rims w/eyelets, what would you all think the top end tension would be? There's no info on the net (the Brave site has no contact info or rim information for some reason), I will email Chain Reaction but they usually take a while to answer. I am guessing around 175 KGF?
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Old 09-17-10, 04:58 PM   #15
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usually 110-120 kgf is common
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Old 09-17-10, 06:42 PM   #16
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usually 110-120 kgf is common

Hmm I seem to have a problem then, I am using double butted spokes, according to park tool gauge the middle of the spokes is 1.8mm and the measurement on some of my spokes on the dished side (disc brake side) is up to 26 which says = 175 KGF.

So I should back off it and not worry as much about the dishing?

My wheels are nearly perfectly true, dangit...

I knew it was too good to be "true". Haha!
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Old 09-17-10, 07:48 PM   #17
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You STILL need to have your wheel dished so that the rim and tire sit centered in the frame. Along with easing off the drive side spokes you need to ease off the non drive side to maintain the dish amount. Obviously the non drive side will be on the low side of acceptable and the drive side on the tight side of acceptable once it all balances out.
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Old 09-17-10, 08:37 PM   #18
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Quote:
Originally Posted by davidad View Post
If you pull a spoke thru the rim you have bought a junk rim. The rim should go out of true when stress relieving when the tension is too high.
Most of my builds are with Mavic rims and they reccomend 110kg max. I may go over or under depending on the expected load.
I haven't pulled a nipple through a rim, I just worry about it.
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Old 09-18-10, 01:22 PM   #19
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..the measurement on some of my spokes on the dished side (disc brake side) is up to 26 which says = 175 KGF.
That is way up there. Mavic Ksyriums (20 spoke) are rated to 160, but you're using a lot for a 32 spoke wheel.

Back down to 110-120. Center & true, then worry about getting the tension even.
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Old 09-18-10, 10:09 PM   #20
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That is way up there. Mavic Ksyriums (20 spoke) are rated to 160, but you're using a lot for a 32 spoke wheel.

Back down to 110-120. Center & true, then worry about getting the tension even.

I'm probably wrong but something doesn't seem right about this force calculation, like, 25 doesn't seem that tight to me based on the feel of the spoke. I am doing the rear wheel now and it is gravitating towards being around 25 as well on the drive side (building an Alfine w/2x pattern, same spokes).
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Old 09-18-10, 11:39 PM   #21
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Never mind, once I backed off all the way around, nothing really changed and I could even true it more easily... it is sitting at the proper tension now.
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Old 09-19-10, 01:30 AM   #22
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...something doesn't seem right about this force calculation, like, 25 doesn't seem that tight to me based on the feel of the spoke.
Now you see the merits of using a tensiometer, and why building by feel is an acquired skill.
25 is way up there, regardless of what your hands and fingers think. Running a wheel at that is quite likely to cause premature cracking by the spoke holes of the rim.
It can even contribute to failure of the hub flanges.
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Old 09-19-10, 03:53 AM   #23
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Now you see the merits of using a tensiometer, and why building by feel is an acquired skill.
25 is way up there, regardless of what your hands and fingers think. Running a wheel at that is quite likely to cause premature cracking by the spoke holes of the rim.
It can even contribute to failure of the hub flanges.
Yes, I realise now two turns of the spoke wrench can bring it from ideal to rim busting tension.. I used the tensionmeter a lot more the second time around, worked out great.. thanks for the help
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Old 09-19-10, 07:03 AM   #24
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..... I used the tensionmeter a lot more the second time around, worked out great..
There is a big part of experience and routine(and the quality of the parts) to wheel building. Once you've gotten your work pattern down pat you can get further and further in the process before breaking out the tensiometer.
As a home tinkerer I think it's impossible to reach good precision (builds are too far between and unlikely to feature the same parts) w/o the use of a meter, but I can see it happening for someone with more continuity to the process.
I built perfectly serviceable wheels w/o one, but I sure can get the tension spread a lot smaller with one.
And when I started on low spoke count wheels I probably would have messed things up real bad w/o the meter. Tensioning to 160 when your muscle memory is set to maybe 120 tops is daunting.

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..... thanks for the help
You're welcome!
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Old 09-19-10, 10:02 AM   #25
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At least the wheels will be stress-relieved!
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