Unequal Spoke Tensions !

[atlantis]

Hi !

I am building a rear wheel disc, 32 hole.
Normal steel round spokes and brass nipples.

The wheel seemed ok , dish was fine, but when I checked the spoke tension with a park tool tensiometer the readings were a bit confusing.

i was aiming for a 120 on the drive side and approx 70 kgf on the nds.

The result on the drive side was alternating, that is one spoke was 120kgf and the neighbouring spoke was 86kgf on the same side.

On the non drive side the same thing happened one spoke was 77kgf and the other was less than 50 approx.

this was throughout the wheel.

Chart
Ds Nds
120 77
86 50
120 77
86 50
120 77
86 50

this happens throughout the wheel.
Can you please tell me where am i going wrong ?

 

[MontyVeda]

probably by using the tensiometer.

I've always been a fan of "If it looks right, it's right"

 

[Yellow Saddle]

Throw away that stupid tool. It contributes nothing.

The difference between left and right tension is a function of the hub flange offset, not some arbritrary numbers. Where did you get 120 and 70 from?

Further, a wheel with equal spoke tensions cannot be true and a true wheel cannot have equal spoke tensions. This is because the rim and spokes are not perfectly uniform. A true wheel is a delicate balance of 33 dissimilar components who all have to be at the tension they have to be to hold the rim straight and round.

 

[I like Skol]

I have built around 15-20 sets of wheels in my lifetime and never used a jig or tensionometer. I did get better over time, almost definitely still not perfect but my wheels stay true and don't require any corrections during their lifetime despite me being a largish lad and giving them some awful abuse so I must be doing something right?
I tend to judge spoke tension by torque required on the spoke key.

 

[e-rider]

120 and 70 equate to 1200 and 700N
The Park Tools tension meter is a useful tool

 

[e-rider]

Throw away that stupid tool. It contributes nothing.

The difference between left and right tension is a function of the hub flange offset, not some arbritrary numbers. Where did you get 120 and 70 from?

Further, a wheel with equal spoke tensions cannot be true and a true wheel cannot have equal spoke tensions. This is because the rim and spokes are not perfectly uniform. A true wheel is a delicate balance of 33 dissimilar components who all have to be at the tension they have to be to hold the rim straight and round.

this response contains many half-truths!

 

[Yellow Saddle]

this response contains many half-truths!

Please feel free to point them out.

 

[the snail]

Maybe you laced the wheel wrongly? Seems odd that the pairs of spokes alternate high/low tension.

 

[fossyant]

You did remember to de-stress the wheel on a regular basis. Ie press hard on the rim so that the spokes can un-twist. It's the success to a true wheel that won't need correcting once in use. You'll have to do this quite a few times

 

[atlantis]

Yes finally got down to work on the wheel !

To rectify this I started working on the Nds spokes and got them to equalize tension, the result was that the Ds got balanced as well. I suppose doesn't sound like the right thing to do, but I got there.

Then gradually checking trueness, dish and tension, completed the wheel.

But somehow this does not solve my problem , as in how I got there?

Please stay on with me , I would like to narrate my wheel build process -

No of spokes -32 (14g normal)
Cross - Triple
Asymmetric pattern
Spoke length seems fine.

After lacing :
1. Turn all nipples upto 2 threads exposed.
2. Turn all nipples until all threads hidden.
3. Give three full turns to Drive Side Ds spokes, one turn at every rotation of the wheel. Inorder to dish to the right
4. Give 1 or 2 full turns on the Non Drive Side Nds.
5. Since I am upto some tension approx 50 Ds and 85 Nds
I start to work on the radial and lateral trueness. Keeping an on dish but not working towards it.
6.Once the wheel starts to take shape, I increase the tension on the spokes as required approx Ds 60 and Nds 100.
7. Destress the wheels, squeeze, press on table.
8 Finalize trueness
9 Dish the wheel.
10. Destress and final check of trueness , tension and dish.

Mostly aiming for a Ds 120 kgf and Nds 70kgf. I was not a fan of tensiometers until I checked one build of mine in which the tensions were all over the place. But in reality that wheel never failed me. But that is another debate, lets not confuse with the current issue at hand.

After reading through this can you'll guide me, as to what attributed the alternate tension scenario ?

 

[Yellow Saddle]

Yes finally got down to work on the wheel !

To rectify this I started working on the Nds spokes and got them to equalize tension, the result was that the Ds got balanced as well. I suppose doesn't sound like the right thing to do, but I got there.

Then gradually checking trueness, dish and tension, completed the wheel.

But somehow this does not solve my problem , as in how I got there?

Please stay on with me , I would like to narrate my wheel build process -

No of spokes -32 (14g normal)
Cross - Triple
Asymmetric pattern
Spoke length seems fine.

After lacing :
1. Turn all nipples upto 2 threads exposed.
2. Turn all nipples until all threads hidden.
3. Give three full turns to Drive Side Ds spokes, one turn at every rotation of the wheel. Inorder to dish to the right
4. Give 1 or 2 full turns on the Non Drive Side Nds.
5. Since I am upto some tension approx 50 Ds and 85 Nds
I start to work on the radial and lateral trueness. Keeping an on dish but not working towards it.
6.Once the wheel starts to take shape, I increase the tension on the spokes as required approx Ds 60 and Nds 100.
7. Destress the wheels, squeeze, press on table.
8 Finalize trueness
9 Dish the wheel.
10. Destress and final check of trueness , tension and dish.

Mostly aiming for a Ds 120 kgf and Nds 70kgf. I was not a fan of tensiometers until I checked one build of mine in which the tensions were all over the place. But in reality that wheel never failed me. But that is another debate, lets not confuse with the current issue at hand.

After reading through this can you'll guide me, as to what attributed the alternate tension scenario ?

What do you mean by alternative tension scenario? I don't get the problem, if there is one.
Secondly, what do you mean by balance? We don't balance bicycle wheels.

 

[Ajax Bay]

The result on the drive side was alternating, that is one spoke was 120kgf and the neighbouring spoke was 86kgf on the same side.
On the non drive side the same thing happened one spoke was 77kgf and the other was less than 50 approx.
this was throughout the wheel.

Chart
Ds Nds
120 77
86 50
120 77
86 50
120 77
86 50

What do you mean by alternative tension scenario? I don't get the problem, if there is one.
Secondly, what do you mean by balance? We don't balance bicycle wheels.

'Alternative tension scenario' = see OP (quoted above) - means 'alternate'.
'Balance' = OP is using this to describe equal tension in all the NDS spokes and, similarly, all the DS spokes.