# non drive side spoke tension



## thalo (Jul 17, 2011)

I have a set of Reynolds attack wheels, used that came with a bike i got used a couple years ago. I rode them for a while and then swapped them out for some alloys (neuvations). i was putting them on my madone last night and with the nifty hidden aero rear brake i came upon some issues with the brake calipers not hitting the rim evenly. i thought it may be an adjustment issue and then thought that the wheel may be out of dish.

i took the wheel into my LBS to work on and it was out of dish. so i worked on getting it trued up and centered. i checked the spoke tension, using the Park Tool Spoke Tension Meter, and was 25+-2 on the drive side but the non drive side was from 10 to 15. with great assumptions i figure that closer to 15 will be better than 10 - 12.

Questions:
1. any idea of what the NDS tension should be, or where I can find the info?
2. (main reason for the post) can i just tighten up the 10-12 deflection spokes to 15? will it have much affect on the trueness of the rim?

cheers
colby


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## Peter P. (Dec 30, 2006)

The non-drive side tension is not a specific number. It will just be what it has to be to balance out the tension on the drive side and keep the wheel dished correctly. There is no real ratio between drive side and non-drive side tension.

If you merely tighten the non-drive side spokes to 15 because of whatever reason, you'll have to increase the drive side tension to pull the wheel back to center. As it stands, there's no way to tell whether the drive side spokes are capable of increased tension. The numbers you mention don't directly translate into kg of tension. 

A wheelbuilder or local bike shop should be able to determine whether the tension of the wheel can be safely increased while keeping the rim dished properly.


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## dcgriz (Feb 13, 2011)

thalo said:


> I have a set of Reynolds attack wheels, used that came with a bike i got used a couple years ago. I rode them for a while and then swapped them out for some alloys (neuvations). i was putting them on my madone last night and with the nifty hidden aero rear brake i came upon some issues with the brake calipers not hitting the rim evenly. i thought it may be an adjustment issue and then thought that the wheel may be out of dish.
> 
> i took the wheel into my LBS to work on and it was out of dish. so i worked on getting it trued up and centered. i checked the spoke tension, using the Park Tool Spoke Tension Meter, and was 25+-2 on the drive side but the non drive side was from 10 to 15. with great assumptions i figure that closer to 15
> 
> ...


1. The NDS to DS tension ratio roughly follows the DS to NDS hub flange offset ratio (I said "roughly" because the length of the spoke based on the lacing pattern also influences the tension ratio).
Example: if your DS tension is at 120kgf and your hub flange offsets are at 16 and 37mm then the NDS tension is expected to be around 51 kgf

2. Short answer: No! You will take the wheel out of true if you just increase the tension on these spokes.
The durability of any wheel is the result of several factors. One of them is maintaining equal tensions across the spokes on the same wheel size (DS or NDS). If you don't, the spokes themselves will upon usage and in the process may loosen up and eventually break. 
Ideally you want to have equal tensions across the DS spokes, a dished wheel and equal tensions across the NDS spokes.

Using the TM meter: Highly repeatable measurements if used properly (same location on the spoke and on the part of the spoke that has the same diameter) but poor absolute tension measurements due to lack of calibration for the specific spoke and tension range. Unless calibrated its best to be used for relative readings between spokes. 
Your 25+-2 graduation readings are IMO a bit too much. I like to see +-0.5.


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## looigi (Nov 24, 2010)

Que sera, sera.


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## cxwrench (Nov 9, 2004)

thalo said:


> I have a set of Reynolds attack wheels, used that came with a bike i got used a couple years ago. I rode them for a while and then swapped them out for some alloys (neuvations). i was putting them on my madone last night and with the nifty hidden aero rear brake i came upon some issues with the brake calipers not hitting the rim evenly. i thought it may be an adjustment issue and then thought that the wheel may be out of dish.
> 
> i took the wheel into my LBS to work on and it was out of dish. so i worked on getting it trued up and centered. i checked the spoke tension, using the Park Tool Spoke Tension Meter, and was 25+-2 on the drive side but the non drive side was from 10 to 15. with great assumptions i figure that closer to 15 will be better than 10 - 12.
> 
> ...


As others have posted...to be sure you understand...

1) There is no recommended NDS tension. It is what it is when the DS is at the correct tension and the rim is centered. 
Sooooooo...
2) How could you increase NDS tension and have the rim stay centered? 

Don't try to out-engineer the engineers that already have jobs in the industry.


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## JCavilia (Sep 12, 2005)

> can i just tighten up the 10-12 deflection spokes to 15? Will it have much effect on the trueness of the rim?


If spokes on one side have differing tensions, but the wheel is laterally true, it means the rim has some inconsistency that requires the uneven tensions to balance. Most rims are somewhat imperfect. Final adjustment of spoke tension is not done by measuring tension, but by observing the trueness of the rim. That's how it works. You get tensions as even as you can, but you make the wheel straight. So it follows that tightening looser spokes on a wheel that's straight will pull it out of line. If it takes unacceptably uneven tensions to make a wheel straight, the rim is no good. (yours does not sound that bad).


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## Kerry Irons (Feb 25, 2002)

JCavilia said:


> If spokes on one side have differing tensions, but the wheel is laterally true, it means the rim has some inconsistency that requires the uneven tensions to balance.


This is true for a well-built wheel, but it can often be a sign of a poorly built (or poorly tensioned after the fact) wheel.


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## thalo (Jul 17, 2011)

Kerry Irons said:


> This is true for a well-built wheel, but it can often be a sign of a poorly built (or poorly tensioned after the fact) wheel.


That is the main reason for my question. Want to make sure that tension is good so that it doesnt go out of true after a short time. I have replaced a rim on one wheel and now have this situation. Trying to get a better handle on the wheel building thing.

Thanks for all the comments.


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## dcgriz (Feb 13, 2011)

thalo said:


> That is the main reason for my question. Want to make sure that tension is good so that it doesnt go out of true after a short time. I have replaced a rim on one wheel and now have this situation. Trying to get a better handle on the wheel building thing.
> 
> Thanks for all the comments.


Typically the DS tension range for steel spokes, including your DT aero comp, is 120-130 kgf and the minimum we strive to end up with on the NDS is preferably above 55kgf but not less than 50 kgf. The wheel reliability at NDS tensions below 50 kgf is at risk because becomes easier for the nipples to further loosen up and the spoke to eventually break.
At 25+-2 you are off the TM-1 chart for a bladed spoke like the DT aero comp which means that either the TM-1 is way off calibration or you got way too much tension (in addition to also being significantly uneven) on the DS or, most probably, both. http://www.parktool.com/documents//85161752fcd5df39d15205f80776303d05e6c84c.pdf. 
IMO, the wheel needs attention. I would expect a properly calibrated meter to read around the 18 mark for the DT aero comp which measure 1.2 x 2.3mm and the acceptable variation should not be more than +-0.5 (17.5-18.5).


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## thalo (Jul 17, 2011)

the wheels have round spokes, not bladed. DT Swiss, maybe Revolution (best I could tell from measurements with my digital calipers that has not battery for digital screen).

I put 25+-2 to cover things but it is probably closer to +-1. I didnt record the numbers for the DS, but did for the NDS after I saw the larger range of values.



dcgriz said:


> The wheel reliability at NDS tensions below 50 kgf is at risk because becomes easier for the nipples to further loosen up and the spoke to eventually break.


This is my main concern. i am going to tighten the lesser valued spokes and make sure that it does not affect the trueness of the wheel.


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## Kerry Irons (Feb 25, 2002)

thalo said:


> i am going to tighten the lesser valued spokes and make sure that it does not affect the trueness of the wheel.


And this may be your path to a poorly built wheel. You need to strive for uniform tension on the drive side (as uniform as the build will allow) and then the NDS tension will fall where it may. Rim non-uniformities may result in high variations on either side and you have to let that happen - it is a reflection of a lower quality or bent rim. Trying to force uniform tension when the rim won't let you is a death spiral.

At some point you have to consider releasing all the spoke tension and starting over.


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## thalo (Jul 17, 2011)

Kerry Irons said:


> And this may be your path to a poorly built wheel. You need to strive for uniform tension on the drive side (as uniform as the build will allow) and then the NDS tension will fall where it may. Rim non-uniformities may result in high variations on either side and you have to let that happen - it is a reflection of a lower quality or bent rim. Trying to force uniform tension when the rim won't let you is a death spiral.
> 
> At some point you have to consider releasing all the spoke tension and starting over.


Okay, so the DS tension is key and NDS kind of is what it is. DS tension is fairly consistent, didnt mark down the measurements but I will just to make sure that things arent varying too much.

I found a tension balance app on the Park Tools site. Thoughts??? Is this something that will be helpful? Park Tool Co. » ParkTool Blog » Wheel Tension Balance App Instructions. Dont know if this is looking too much into it.

went through the Musson guide to check on anything else about the subject. Thanks for all the insight.


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## looigi (Nov 24, 2010)

thalo said:


> Okay, so the DS tension is key and NDS kind of is what it is. ..


Correct, except for the "kind of". There is no ambiguity. It can't be any more or less than what is needed to center the rim, otherwise the rim wouldn't be centered.


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## thalo (Jul 17, 2011)

looigi said:


> Correct, except for the "kind of". There is no ambiguity. It can't be any more or less than what is needed to center the rim, otherwise the rim wouldn't be centered.


Sure, it is what it is to make it true, etc. Now I understand your previous comment.


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## Clipped_in (May 5, 2011)

Kerry Irons said:


> And this may be your path to a poorly built wheel. You need to strive for uniform tension on the drive side (as uniform as the build will allow) and then the NDS tension will fall where it may. Rim non-uniformities may result in high variations on either side and you have to let that happen - it is a reflection of a lower quality or bent rim. *Trying to force uniform tension when the rim won't let you is a death spiral.*
> At some point you have to consider releasing all the spoke tension and starting over.


Kerry, I'm always interested in what you have to say and once again you deliver!


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