Wheel build... what would you do?

[coachboyd]

Originally Posted by Mark McM

We know that the spokes are the same material, so we know they have the same density and modulus. We also know that the weights of the spokes are virtually the same (Pillar says 4.3g for a 260mm spoke, Sapim says 272g for 64 260mm spokes, or 4.25g each). We know that both have 2.0mm short threaded sections. We know that the short elbow sections are 2.2mm for the Pillar and 2.0mm for the Sapim - but we know the ends are so short that they comprise only a small portion of the spoke weight, and also a small portion of the spoke . We elongation under load. We know that the vast majority of the spoke weight is in the long middle section, so we therefore know that the long middle sections of each spoke are very similar in length and cross sectional area. And because the middle sections are similar in length and cross-sectional area, we know the middles will have similar stiffness. And because the know the long middle sections have most of the spoke elongation, we therefore know the two spokes will have similar overall longitudinal stiffnesses.

Finally, we know the dimensional analysis above is a far better indicator of spoke longitudinal stiffness, than is the comparisons of the bending stiffness of the middle sections of the spokes (as claimed by Boyd).

Hey there, first of all the reason why we switched to Pillar has nothing to do with the price. The spoke itself is slightly less expensive than a CX Ray, however when you factor landed costs we are right around a dollar on a wheelset. We wouldn't risk using an inferior product just for a dollar savings per wheel. Having two wheels per year with an issue would wipe out all that potential savings.

The fact that the elbow is 2.2mm on a Pillar and 2.0 on other spokes does not contribute at all the stiffness of the wheel, but it helps a lot with preventing broken spokes over time. It makes a much tighter fit between the spoke and the hole drilling of the hub, plus the larger cross section does make the elbow stronger. We never had a huge issue with broken spokes, but they have drastically reduced since moving to Pillar.

The thicker cross section absolutely helps with wheel stiffness. Round spokes build up a stiffer wheel compared to aero spokes because they are thicker side to side. Take a typical round double butted spoke that has a cross section of 1.8mm (the whole way around as it's a circle). Bladed spokes are made from round double butted spokes and then stamped to make the bladed shape (so the amount of material in a round double butted spoke and a bladed spoke are the exact same).
Typical stamping will make a flat shape. When this happens you get the consistent .88mm the whole way across the spoke. This allows the rim to move back and forth much easier that a 1.8 cross section.

Pillar has made a stamping process that instead of making a flat shape makes a wing shape. The very center part of the spoke will be just over 1.2mm thick. There has been aero testing done on flat bladed vs wing shape. There's basically no real difference between the two (but then there's also not really much of a difference between round and "aero" spokes either). We never made a claim that there would be aero improvements by switching to Pillar, just that there would not be a decrease.

So basically; the thicker elbow was the major decision to switch. However, the better cross section thickness (without an aero penalty), and the fact that this comes with no weight penalty are big added bonuses.

[Mark McM]

Originally Posted by coachboyd

The thicker cross section absolutely helps with wheel stiffness. Round spokes build up a stiffer wheel compared to aero spokes because they are thicker side to side. Take a typical round double butted spoke that has a cross section of 1.8mm (the whole way around as it's a circle). Bladed spokes are made from round double butted spokes and then stamped to make the bladed shape (so the amount of material in a round double butted spoke and a bladed spoke are the exact same).

I'm sorry, but this is just plain wrong. Spokes are one force members, and are only loaded in axial tension. This due to several factors - firstly, they are attached at rotatable anchors (if the heads and nipples couldn't rotate, then the couldn't accommodate different spoke crossings and bracing angles); and all spokes, regardless of thickness are so flexible in bending that their bending stiffness make no meaningful contribution to the stiffness of the wheel. Because spokes are loaded only in axial tension, only their axial stiffness contributes to the stiffness of the wheel. Spoke axial stiffness is dependent on the area of its cross-sections but not the shape of its cross-section. Two spokes with same cross sectional area will have the same axial stiffness, regardless of whether they are round or flat.

For more about how wheels work, I suggest having a read of the The Bicycle Wheel by Jobst Brandt

[mstateglfr]

[oldpotatoe]

Originally Posted by Mark McM

I'm sorry, but this is just plain wrong. Spokes are one force members, and are only loaded in axial tension. This due to several factors - firstly, they are attached at rotatable anchors (if the heads and nipples couldn't rotate, then the couldn't accommodate different spoke crossings and bracing angles); and all spokes, regardless of thickness are so flexible in bending that their bending stiffness make no meaningful contribution to the stiffness of the wheel. Because spokes are loaded only in axial tension, only their axial stiffness contributes to the stiffness of the wheel. Spoke axial stiffness is dependent on the area of its cross-sections but not the shape of its cross-section. Two spokes with same cross sectional area will have the same axial stiffness, regardless of whether they are round or flat.

For more about how wheels work, I suggest having a read of the The Bicycle Wheel by Jobst Brandt

Yee Haa..I am SO glad I aren't an engineer...so I won't make any claims that require 'science', as a wheel builder.

BUT, lotsa hype and marketing going into CxRay 'type' spokes, and lotsa claims about the YUGE increase in performance...BUT..at $4 per spoke(CXRay), yikes, don't see the point.

Out

[tellyho]

I have built and ridden a bunch of wheels with both Bitex and DT hubs, 350 and 240, using Pillar spokes. All have been great and I have beaten the s**t out of several of these wheelsets. My current 29er wheels are Bitex hubs, as were my prior set. Never had any reliability issues and would not hesitate to use them again. POE is great for my purposes. More recently, I've leaned toward DT hubs because I really like the simplicity, design and serviceability of the star ratchet mechanism. So, for me, I'd likely go DT and Pillar. I use basic DB spokes; don't ride fast enough to see any benefit from bladed spokes. I don't know that there is any difference among the major spoke brands that I could discern as a rider; for me it's $.

[deluz]

I have built a fair number of wheels all being alloy and they all have performed well. I have a Park TM-1 tensiometer and realize it is not the most accurate tool but probably better than nothing. I will soon be building my first pair of carbon wheels and thinking of springing for a Wheel Fanatik tensiometer.
Since there are no tension charts that I know of for Pillar wing spokes I asked Ric at Wheel Fanatik about this. His response:

Charts apply to most non-round shapes because:
Spokes used to generate the columns are the most popular shapes with that minimum thickness. For 0.9–1.4, the shapes are elongated flat rectangles, ellipses, and wings. So the numbers are suited.
The tensiometer's design, the very light deflection load, is key to measuring stiffness based on thickness more than mass/shape.

I am not sure this makes sense, it seems to me that the tension measurement would depend on cross section area of the spoke and two spokes with the same thickness could have significantly different cross sectional area.
I am not sure it is worth spending the money on this tool if there is no accurate calibration to this spoke. I could build a calibration fixture using a spoke tensioned with a crane scale but that is getting even more expensive and I am not in the business of building wheels. Park tool referred me to their wheel tension app where you can enter the spoke dimension and specify round or blade shape. The Pillar is really neither shape but blade might be close enough. Being an engineer I always try to understand things from a mathematical and scientific viewpoint, but there some things where it is more art than science and I think wheel building has an element of that.

[Mark McM]

Originally Posted by deluz

I have built a fair number of wheels all being alloy and they all have performed well. I have a Park TM-1 tensiometer and realize it is not the most accurate tool but probably better than nothing. I will soon be building my first pair of carbon wheels and thinking of springing for a Wheel Fanatik tensiometer.
Since there are no tension charts that I know of for Pillar wing spokes I asked Ric at Wheel Fanatik about this. His response:

Charts apply to most non-round shapes because:
Spokes used to generate the columns are the most popular shapes with that minimum thickness. For 0.9–1.4, the shapes are elongated flat rectangles, ellipses, and wings. So the numbers are suited.
The tensiometer's design, the very light deflection load, is key to measuring stiffness based on thickness more than mass/shape.

I am not sure this makes sense, it seems to me that the tension measurement would depend on cross section area of the spoke and two spokes with the same thickness could have significantly different cross sectional area.
I am not sure it is worth spending the money on this tool if there is no accurate calibration to this spoke. I could build a calibration fixture using a spoke tensioned with a crane scale but that is getting even more expensive and I am not in the business of building wheels. Park tool referred me to their wheel tension app where you can enter the spoke dimension and specify round or blade shape. The Pillar is really neither shape but blade might be close enough. Being an engineer I always try to understand things from a mathematical and scientific viewpoint, but there some things where it is more art than science and I think wheel building has an element of that.

Tension meters apply a side load to the spokes, and then measure the resultant lateral deflection. The three main factors that will determine the amount of deflection are the magnitude of the side load, the tension in the spokes, and the lateral stiffness of the spoke. However, minimizing the side load will decrease the amount of deflection due to the spoke's lateral stiffness, giving a more precise measurement of the tension. The downside of using a smaller side load is that you need a more sensitive and precise gauge.

The Wheel Fanatyk tension meter (which is based on the design originated by Jobst Brandt) uses a relatively small side load, minimizing the affect of the spoke's lateral stiffness. Another feature of the Brandt design is that it only contacts the spoke on on side, so the gauge reading measures only the deflection from the side load, and does not include the spoke thickness. In contrast, "scissors" type tension meters (such as the WheelSmith tension meter) contact both sides of the spokes, so the measurement includes both the spoke thickness and the deflection under side load. Scissors type tension meters can be thrown off by variations in spoke thickness, while Brandt type tensions meters are much less sensitive to variations in spoke thickness.

So, this is why Wheel Fanatyk tension meter can give precise readings over a wide range of spoke thicknesses and cross sectional shapes.

[deluz]

Originally Posted by Mark McM

Tension meters apply a side load to the spokes, and then measure the resultant lateral deflection. The three main factors that will determine the amount of deflection are the magnitude of the side load, the tension in the spokes, and the lateral stiffness of the spoke. However, minimizing the side load will decrease the amount of deflection due to the spoke's lateral stiffness, giving a more precise measurement of the tension. The downside of using a smaller side load is that you need a more sensitive and precise gauge.

The Wheel Fanatyk tension meter (which is based on the design originated by Jobst Brandt) uses a relatively small side load, minimizing the affect of the spoke's lateral stiffness. Another feature of the Brandt design is that it only contacts the spoke on on side, so the gauge reading measures only the deflection from the side load, and does not include the spoke thickness. In contrast, "scissors" type tension meters (such as the WheelSmith tension meter) contact both sides of the spokes, so the measurement includes both the spoke thickness and the deflection under side load. Scissors type tension meters can be thrown off by variations in spoke thickness, while Brandt type tensions meters are much less sensitive to variations in spoke thickness.

So, this is why Wheel Fanatyk tension meter can give precise readings over a wide range of spoke thicknesses and cross sectional shapes.

I don’t really understand the physics behind why a smaller side load makes the measurement independent of spoke shape and cross section, but I will just trust it is valid and get on with wheel building.

[oldpotatoe]

I use a DT dial tension-meter BUT, use SOMETHING. The old, 'may hands can tell' or the 'I can tell by tone' is mostly bugle oil..get a decent tension-meter. I have a Wheelsmith one as a backup..dropped the DT one and had to have it re-calibrated..needed a spare 'something'.

I had a Wheel Fanatik one but didn't like it so sold it.

Same goes for a decent torque wrench.

[November Dave]

One interesting thing I've found with the simple consumer version Park Tool tension meter that maybe Mark or someone else can chime in on. They're fairly useless in the absolute ("what tension is this spoke at") but they are very accurate in determining "is this spoke at the same tension as that one?"

So when I need to find out if the disc side spokes of a front wheel are "about 110kgf" the Sapim dial meter is my primary tool there, but when I hear a tonal difference in two spokes on the drive side of that wheel and want to find out if I need to back the tighter one off 1/8 of a turn and put that 1/8 turn onto the looser one, the Park Tool meter is better at picking that difference up.

[culler763]

I have had great experience with Novatech hubs and miserable experience with CK - they are a pain to adjust.

[deluz]

Originally Posted by oldpotatoe

I use a DT dial tension-meter BUT, use SOMETHING. The old, 'may hands can tell' or the 'I can tell by tone' is mostly bugle oil..get a decent tension-meter. I have a Wheelsmith one as a backup..dropped the DT one and had to have it re-calibrated..needed a spare 'something'.

I had a Wheel Fanatik one but didn't like it so sold it.

Same goes for a decent torque wrench.

What did you not like about the WF tension meter?

[Old School]

Originally Posted by fredd

You might like this read about pillar wing vs CX rays. Might just be boyd justifying the cheaper option, but could help you rest easy after choosing pillar.

I was going to comment in this thread about my own experiences with Sapim vs Pillar, and was pleasantly surprised to find I am not a alone!!!!!

[Old School]

Originally Posted by culler763

I have had great experience with Novatech hubs and miserable experience with CK - they are a pain to adjust.

Depending on how many miles, Novatecs wear out, and cost more to repair than to replace. My experience on a MTB is maybe 5000 miles and they need modified, repaired, or replaced with something new.

[deluz]

Originally Posted by November Dave

One interesting thing I've found with the simple consumer version Park Tool tension meter that maybe Mark or someone else can chime in on. They're fairly useless in the absolute ("what tension is this spoke at") but they are very accurate in determining "is this spoke at the same tension as that one?"

So when I need to find out if the disc side spokes of a front wheel are "about 110kgf" the Sapim dial meter is my primary tool there, but when I hear a tonal difference in two spokes on the drive side of that wheel and want to find out if I need to back the tighter one off 1/8 of a turn and put that 1/8 turn onto the looser one, the Park Tool meter is better at picking that difference up.

Why do you say the Park meter is useless for absolute tension measurement? I have sent mine back to Park for calibration at one point. The wheels I have built with it have been fine.
Another possibility is to keep using my Park TM-1 and build myself a calibration fixture. it is fairly easy to do and costs about $100 in parts.
That way I can calibrate it for any spoke at any tension.