Preventing spokes unwinding

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alexnharvey
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Re: Preventing spokes unwinding

Postby alexnharvey » 21 Apr 2019, 2:57pm

I don't have direct experience of threadlock on nipples. My experience of adding oil to lubricate them before adjusting is that it's quite easy to apply it to the nipple well by running it down the spoke and it disappears somewhere when the wheel is spun.

Brucey
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Re: Preventing spokes unwinding

Postby Brucey » 21 Apr 2019, 4:40pm

Gattonero wrote:That is very optimistic, in reality doesn't work that well and the threadlock will spill all around outside the nipple before going inside it....


I know it works very well because I have done it many times. The calculation merely helps to explain why.

As I said before there is plenty of room for a useful amount of threadlock between the spoke and the (tapered) opening in the nipple. If you put too much on the excess spills over, but that doesn't suddenly mean there is none where you need it....

In a similar vein if you have an old-ish wheel with partially corroded/seized nipples, applying oil in the same way (a week or so ahead of time) can make the difference between the nipples moving and not. The more you ride the wheel in the meantime, the better the oil penetrates.

cheers
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iandusud
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Re: Preventing spokes unwinding

Postby iandusud » 22 Apr 2019, 6:36am

I would suggest that the most likely cure is more tension in the spokes. I used to build / rebuild wheels every working day for many years and never had problems with spokes loosening on my wheels. I did however see lots of new wheels that lost their tension very quickly: they all had the same fault in that they weren't built with enough tension to start with (usually generic wheels on new bikes).

Ian

fatboy
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Re: Preventing spokes unwinding

Postby fatboy » 22 Apr 2019, 7:29am

iandusud wrote:I would suggest that the most likely cure is more tension in the spokes. I used to build / rebuild wheels every working day for many years and never had problems with spokes loosening on my wheels. I did however see lots of new wheels that lost their tension very quickly: they all had the same fault in that they weren't built with enough tension to start with (usually generic wheels on new bikes).

Ian


That's what I thought but I cannot get any more tension into the wheel without it pringling. So may be the choice of rim (Mavic Open Elite) not allowing me to put enough tension in. I'm going to Loctite the NDS spokes and see if that helps.
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Samuel D
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Re: Preventing spokes unwinding

Postby Samuel D » 22 Apr 2019, 7:36am

The Open Elite (and the Open Pro you first said you were using) do have a lower tension limit than some rims. It’s still well over 100 kg, though.

You still haven’t mentioned what hub you’re using. I for one am curious about that and your weight.

Brucey
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Re: Preventing spokes unwinding

Postby Brucey » 22 Apr 2019, 9:54am

it depends very much on the rider too. I know I can't build a rear wheel for me (or one or two of my chums) using an Open Elite (formerly known as Open Sport, MA3 more or less) in a conventionally dished wheel (130mm/8s) unless the NDS nipples are threadlocked.

As suggested above it doesn't matter what the base tension in the wheel is; with this particular rim you will get a pringle before you get enough tension in the NDS spokes (for this rim, this dish, with an aggressive rider). With 7s/135mm it works OK, because the tension balance is more in your favour to start with.

cheers
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fatboy
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Re: Preventing spokes unwinding

Postby fatboy » 22 Apr 2019, 2:04pm

Samuel D wrote:The Open Elite (and the Open Pro you first said you were using) do have a lower tension limit than some rims. It’s still well over 100 kg, though.

You still haven’t mentioned what hub you’re using. I for one am curious about that and your weight.


Hubs are Sora and I'm around 85 to 90 kg so not light
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MikeDee
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Re: Preventing spokes unwinding

Postby MikeDee » 22 Apr 2019, 3:24pm

There is wicking Loctite (expensive) that I would recommend using. More tension is not the answer, assuming that the spokes are already at the tension recommended by the rim manufacturer; rim cracking will result. Large variations in spoke tensions can cause the loose ones to unwind, so balance the spoke tensions. NDS spokes are particularly prone to loosening.

Samuel D
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Re: Preventing spokes unwinding

Postby Samuel D » 23 Apr 2019, 12:17am

fatboy wrote:Hubs are Sora and I'm around 85 to 90 kg so not light

Not light but not unusually heavy, and Sora hubs, even the latest ones, have less offset than comparable Shimano 11-speed hubs. So I’m slightly surprised at your trouble! Oh well.

Brucey
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Re: Preventing spokes unwinding

Postby Brucey » 23 Apr 2019, 6:39am

part of the issue here is that the Open Elite rim is a rim design that is not especially stiff, by modern standards (it is basically a slight revision to the Open Sport/MA3 design). Another part of the issue is that whilst the rim is superficially similar to its predecessors, it may differ enough in detail to cause it to behave differently; in particular the braking surface may be machined thinner and the hardness of the aluminium alloy may be less. The former affects the stiffness of the rim directly and the latter affects the chances of the rim getting deformed.

When the rim 'pringles' it is an elastically initiated collapse of the wheel. Things that help precipitate it are high overall spoke tension, wheel dish, uneven spoke tension, imperfect rim straightness/rim loading, and low rim stiffness. In theory a pringle can arise and the only deformation of the rim is elastic, i.e. the rim should pop back perfectly straight. However if the rim is not especially strong, and/or sees uneven stress (eg at a pinned joint) when pringled it may be permanently deformed, and the rim may be more vulnerable to a repeat pringle or other problem. IME this type of rim tends to pringle at a spoke tension that is not much in excess of the tension limit (which is set to avoid cracking) for the rim anyway; if it has pringled once, it may pringle again more easily. If you are close to a pringle, another way of looking at it is that the amount of lateral force required to cause a pringle is lessened, and/or that the service-induced spoke tension variations are greater than normal too.

More modern rim designs are inherently stiffer (in torsion) and are more resistant to pringling. However I think that slight changes in manufacturing practice may have made this rim design a mere shadow of its former self. When rim braking surfaces started to be machined, rims that were already very straight were rendered 'perfect'. However it seems to me that (as part of the relentless 'race to the bottom') they now machine rims that are not very straight and expect them to be OK; they are of course often no such thing; they vary in wall thickness and so far as service-induced spoke tension variations and risk of pringling/NDS loosening are concerned, this is as bad as a rim that is nowhere near straight and/or one that is built with uneven spoke tension; you could get two nominally identical rims and they could be like chalk and cheese to build with.

So my advice to the OP is to use threadlock on the NDS nipples for sure, but if you want to go the final mile, I suggest that you measure the rim wall thickness (and straightness with the spokes completely slack) and compare it with the front rim. If the front rim is better than the rear, swap the rims over; you may end up with a noticeably better wheelset.

cheers
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NATURAL ANKLING
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Re: Preventing spokes unwinding

Postby NATURAL ANKLING » 23 Apr 2019, 11:37am

Hi,
My Raleigh wheels stayed true as a die for years, problem came when re-rimming the rear wheel.
Pulled my hair out several times :twisted: :cry:
The original spokes obviously used a threadlock, nipples squealed all the way out.
14 front 13 swg back, Plain gauge. Without checking the rear would of been same size both sides, but it could of been 13 left 14 right, yes no, wrong way round?
8S deore lx hub. Mavic t261 rim. (whats nearest equivalent rim today?)
I ended up using 12-13-12, though ACI are a thou down on the sizes.
I think there is still very minor movement of nipples NDS, I tend to wrestle the bike a lot.

Do commercial wheel builders ever use threadlock?
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hamster
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Re: Preventing spokes unwinding

Postby hamster » 23 Apr 2019, 12:13pm

One point on that is the 8S LX hub will be 135mm OLN and therefore have less horrible dish - and more equal spoke tensions.

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NATURAL ANKLING
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Re: Preventing spokes unwinding

Postby NATURAL ANKLING » 23 Apr 2019, 5:27pm

Hi,
hamster wrote:One point on that is the 8S LX hub will be 135mm OLN and therefore have less horrible dish - and more equal spoke tensions.

Maybe, its ok with DB spokes but from the factory all the spokes were plain and thread locked.

One point I think that been mentioned by Brucey in the past about getting less dish is moving the freehub closer to the frame.
The LX hub is a 8-9 speed and the washer is still inplace too.
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hoogerbooger
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Re: Preventing spokes unwinding

Postby hoogerbooger » 24 Apr 2019, 2:45pm

my LBS uses PTFE tape on the thread instead of oiling and I think their reasoning was it both lubricates when building the wheel and helps prevent loosening up. ( I have no idea how it could do both ? but their wheels seemed to stay straight)

Brucey
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Re: Preventing spokes unwinding

Postby Brucey » 24 Apr 2019, 2:52pm

seems reasonable to me, but a bit fiddly to do.

cheers
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