[rmsmith]

The drive side spokes have almost twice the tension of the non-drive side, so would you use larger spokes to balance the stretch in an effort to improve the time between spoke tension maintenance?

Please see the attachment. Thanks!

 

[TurboTurtle]

The drive side spokes have almost twice the tension of the non-drive side, so would you use larger spokes to balance the stretch in an effort to improve the time between spoke tension maintenance?

Please see the attachment. Thanks!

First, 'stretch' is a good thing. Without it the spokes would de-tension= bad.

Spoke tension maintenance is only required if the nipple turns, the spoke length changes or the hub-to-rim length changes. How would a larger spoke prevent any of these?

TF

 

[Marc]

If your wheel needs spoke adjusting (as a result of JRA)--it means your wheels probably weren't built that well to begin with.

DS and NDS spokes are different lengths, but changing the respective gauges really won't change that much on a properly built wheel. You'll still have the same load on the spokes.

 

[rmsmith]

First, 'stretch' is a good thing. Without it the spokes would de-tension= bad.

Exactly my point, TT. With the same diameter spokes the non-drive side spokes have less stretch because they have roughly half the tension. As for spoke length there is less than 1% difference between the two sides, so tension per unit cross sectional area is really the issue.

 

[Marc]

Exactly my point, TT. With the same diameter spokes the non-drive side spokes have less stretch because they have roughly half the tension. As for spoke length there is less than 1% difference between the two sides, so tension per unit cross sectional area is really the issue.

Remember on a properly built 32-spoke wheel, your spokes will have ~120 kgf (+/- 10%) of tension (each). The cross-sectional area difference between a 14 gauge (2 mm diameter) and a 15 gauge (1.8 mm diameter) spoke is moot under those circumstances of load. Even then, steel stretches very little while under load. Moreover when you factor in that spokes, hubs, and rims are not ideal--thus you can end up having a +/- 20% difference in tension (even on good quality parts)--any small gains that might be had in using different gauge spokes disappear. The difference in average load per mm^2 is only ~15% anyway between 14s and 15s at the same load and between drive side and non-drive side there's only a 30-40% (ideal) difference in tension, and a difference of about 30% in load per unit area (DS vs NDS).....which as stated all these differences can get swallowed up or expanded upon given how ideal or not the rims, spokes, and hubs are.


Changes in spoke tension shouldn't be an issue on a wheel that is tensioned, stress relieved and has the spokes thread-locked.

 

[Mike T.]

.....would you use larger spokes to balance the stretch in an effort to improve the time between spoke tension maintenance?

How much time would you like? Five, ten, fifteen years? I've got homebuilt wheels (with equal diameter spokes) that have gone that long (and will go lots more) without tension maintenance.

If tension maintenance is required it sure as heck isn't the fault of spoke gauges being the same.

 

[TurboTurtle]

Exactly my point, TT. With the same diameter spokes the non-drive side spokes have less stretch because they have roughly half the tension. As for spoke length there is less than 1% difference between the two sides, so tension per unit cross sectional area is really the issue.

The NDS spokes are going to have the same tension no matter what the DS spokes are. You are just decreasing the 'stretch' of the DS spokes. - TF

 

[eddie m]

I use straight gauge on he drive side and butted on the non-drive side. Straight gauge on the non-drive side can go slack under load and fatigue. The lighter spoke has a longer life because it is pre-loaded (stretched) enough that it never goes slack. I like straight gauge in the drive side because they are cheaper, easier to build with because they resist wind-up better than butted spokes, and they make the wheel a little stiffer laterally, which I think is important for safety. A lot of wheel builders prefer all butted spokes, but I'm a big guy and I like more lateral stability.
em

 

[eddie m]

The NDS spokes are going to have the same tension no matter what the DS spokes are. You are just decreasing the 'stretch' of the DS spokes. - TF

Not exactly. The load and cross-section the drive side spokes have determines the amount of stretch. The non-drive side spokes have no effect on that.
Lghter gauge spokes will always stretch more, so the only issue is whether the low tension spokes stretch enough to remain tensioned at all times.

em

 

[eddie m]

Remember on a properly built 32-spoke wheel, your spokes will have ~120 kgf (+/- 10%) of tension (each). The cross-sectional area difference between a 14 gauge (2 mm diameter) and a 15 gauge (1.8 mm diameter) spoke is moot under those circumstances of load. Even then, steel stretches very little while under load. Moreover when you factor in that spokes, hubs, and rims are not ideal--thus you can end up having a +/- 20% difference in tension (even on good quality parts)--any small gains that might be had in using different gauge spokes disappear. The difference in average load per mm^2 is only ~15% anyway between 14s and 15s at the same load and between drive side and non-drive side there's only a 30-40% (ideal) difference in tension, and a difference of about 30% in load per unit area (DS vs NDS).....which as stated all these differences can get swallowed up or expanded upon given how ideal or not the rims, spokes, and hubs are.

The difference in coss-section area between a 2 mm spoke and a 1.8 mm spoke is almost 25%, not 14%. The difference in load between the left and right sides can be as much as 50% (see the OP's example). Those differences are large enough to require different gauge spokes. It makes a more robust wheel than using fewer spokes on the left side, which is another solution for the same problem.

Changes in spoke tension shouldn't be an issue on a wheel that is tensioned, stress relieved and has the spokes thread-locked.

The issue isn't changes in tension, it is that lightly loaded heavy gauge spokes lead to early fatigue failure.

 

[TurboTurtle]

The NDS spokes are going to have the same tension no matter what the DS spokes are. You are just decreasing the 'stretch' of the DS spokes. - TF
--------------------------------------------------------------
Not exactly. The load and cross-section the drive side spokes have determines the amount of stretch. The non-drive side spokes have no effect on that.
Lghter gauge spokes will always stretch more, so the only issue is whether the low tension spokes stretch enough to remain tensioned at all times.

em
--------------------------------------------------------------

"Not exactly" what? I said two things:

1 - "The NDS spokes are going to have the same tension no matter what the DS spokes are." Are you saying that the diameter of the DS spokes at the same tension will change the tension of the NDS spokes?

2 - "You are just decreasing the 'stretch' of the DS spokes." Are you saying changing the diameter of the DS spokes does not change their stretch?

TF

 

[Marc]

The issue isn't changes in tension, it is that lightly loaded heavy gauge spokes lead to early fatigue failure.

You misread my post.


I would not classify a spoke with 70kgf +/-10% on it as "lightly loaded"-unless the rider is of the much heavier persuasion; in which case they should have beefier wheel anway. If spokes are lightly loaded--they'll fail due to metal fatigue regardless of gauge.

I have a pair of ultegra-CXP33-32X14/15/14 DT laced 3X--same dreaded gauge on DS and NDS that haven't needed any rim or spoke maintenance in 3 or 4 years since they were built--apart from some truing on the front after a run-in with a large German shepard. I built them so DS and NDS are within 10-15% of 120kgf and 70kgf respectively and I weigh ~165lbs.

 

[rruff]

The drive side spokes have almost twice the tension of the non-drive side, so would you use larger spokes to balance the stretch in an effort to improve the time between spoke tension maintenance?

If you have high radial loads, using lighter spokes on the NDS will reduce the amount of detension they see (ie higher load before going slack). Basically, since the DS spokes are stiffer, they will see a greater change in force for the same rim deflection... in other words, the DS will take a greater percentage of the radial load compared to having the same gauge spokes on both sides. IMO it is generally a good practice... especially with a shallow rim. However, you will lose some lateral stiffness compared to using the heavier spokes on both sides.

 

[eddie m]

I would not classify a spoke with 70kgf +/-10% on it as "lightly loaded"-unless the rider is of the much heavier persuasion; in which case they should have beefier wheel anway. If spokes are lightly loaded--they'll fail due to metal fatigue regardless of gauge.

I have a pair of ultegra-CXP33-32X14/15/14 DT laced 3X--same dreaded gauge on DS and NDS that haven't needed any rim or spoke maintenance in 3 or 4 years since they were built--apart from some truing on the front after a run-in with a large German shepard. I built them so DS and NDS are within 10-15% of 120kgf and 70kgf respectively and I weigh ~165lbs.

In your example, the left side spokes are loaded to about 40% of their yield strength, so they are not "lightly loaded," but the drive side are loaded to about 66%. You would have better durability if you used stronger spokes on the drive side.
There are several ways to deal with the asymmetry of bicycle wheels. You can use an offset rim, you can use fewer spokes on the left side, or you can use lighter spokes on the left side. If you not doing any of those, you are not optimizing all the variables, and you will end up with a wheel that is weaker or heavier than necessary, or, ironically, weaker AND heavier than necessary.

em

 

[eddie m]

If you have high radial loads, using lighter spokes on the NDS will reduce the amount of detension they see (ie higher load before going slack). Basically, since the DS spokes are stiffer, they will see a greater change in force for the same rim deflection... in other words, the DS will take a greater percentage of the radial load compared to having the same gauge spokes on both sides. IMO it is generally a good practice... especially with a shallow rim. However, you will lose some lateral stiffness compared to using the heavier spokes on both sides.

+1
The loss in lateral stiffness on the left side is usually a good trade off. The left side allows less lateral movement than the drive side because it has a greater staying angle. Heavier drive side spokes add lateral stiffness to that side, where it is needed most. That's an important consideration for me, because I'm a big guy.

em

 

[eddie m]

The NDS spokes are going to have the same tension no matter what the DS spokes are. You are just decreasing the 'stretch' of the DS spokes. - TF
--------------------------------------------------------------
Not exactly. The load and cross-section the drive side spokes have determines the amount of stretch. The non-drive side spokes have no effect on that.
Lghter gauge spokes will always stretch more, so the only issue is whether the low tension spokes stretch enough to remain tensioned at all times.

em
--------------------------------------------------------------

"Not exactly" what? I said two things:

1 - "The NDS spokes are going to have the same tension no matter what the DS spokes are." Are you saying that the diameter of the DS spokes at the same tension will change the tension of the NDS spokes?

2 - "You are just decreasing the 'stretch' of the DS spokes." Are you saying changing the diameter of the DS spokes does not change their stretch?

TF

1-I agree that the diameter of the drive side has no effect on the tension on the non-drive side. Lighter spokes will have the same tension but will be more stressed, and they will stretch more.
2- At the same tension, larger diameter spokes will stretch less, regardless of what side they are on. I think that's what I wrote.

em

 

[rruff]

+1
The loss in lateral stiffness on the left side is usually a good trade off. The left side allows less lateral movement than the drive side because it has a greater staying angle. Heavier drive side spokes add lateral stiffness to that side, where it is needed most.

A misconception there. The lateral stiffness of the wheel is the same in both directions... and the stiffness imparted by the spokes is nearly proportional to bracing angle squared. So the NDS spokes have by far the greatest influence on stiffness.

I think the best way to deal with a dished wheel is triplet lacing (twice the spokes on the DS) with a special hub that has a wide NDS bracing angle... with one caveat... if you break a NDS spoke the wheel tends to go *way* out of true, probably locking the wheel.

 

[TurboTurtle]

1-I agree that the diameter of the drive side has no effect on the tension on the non-drive side. Lighter spokes will have the same tension but will be more stressed, and they will stretch more.
2- At the same tension, larger diameter spokes will stretch less, regardless of what side they are on. I think that's what I wrote.

em

So you disagreed and then said the same thing I said. ???? - TF

 

[eddie m]

A misconception there. The lateral stiffness of the wheel is the same in both directions... and the stiffness imparted by the spokes is nearly proportional to bracing angle squared. So the NDS spokes have by far the greatest influence on stiffness.

I think the best way to deal with a dished wheel is triplet lacing (twice the spokes on the DS) with a special hub that has a wide NDS bracing angle... with one caveat... if you break a NDS spoke the wheel tends to go *way* out of true, probably locking the wheel.

There's no misconception. You are right that the stiffness of the wheel is the same in both directions, but I think maybe the wheel gets a lot more unstable when it flexes one way or the other. I know that's not what I wrote above, but that's what I was thinking about at the time. I can't prove it, I'm not sure how to analyze it and I don't want to do any destructive testing, but I think that it's true that the wheel gets more unstable as it flexes to the drive side.

Triple lacing is the best solution whenever you have a neutral support van.

em

 

[eddie m]

So you disagreed and then said the same thing I said. ???? - TF

I didn't contradict myself. I think we are both misreading each others words.

em