[Circlip]

In a discussion in another sub forum, another user and I aren't seeing eye to eye on the topic of whether either of CX Rays or Lasers will build a more "compliant" wheel. Rather than clog up the other discussion I decided to bring it over here where people think about and discuss such questions.

More generically, I suppose the question is what ride qualities 2 otherwise wheels will have if one is built with bladed spokes, and the other with round spokes, assuming both spokes have the same cross section area as is the case with the Lasers and CX Rays.

My position was that both wheels would have the same ride characteristics, for practical purposes. The other user states that the Lasers will build a more compliant wheel than CX Rays, for the reasons of differences in "factors such as the shape, Ultimate Tensile Strength and how much the spokes need to be tensioned".

"Compliance" was not yet defined in our discussion, meaning it's open game to talk about either or both of vertical, lateral, etc.

For simplicity and relevance, let's ignore the aerodynamics aspect of this comparison.

While our discussion in the other sub forum unfortunately took on an adversarial tone, I am genuinely interested in opinions to advance my own knowledge. I build wheels for myself when needed, and occasionally for friends, using both bladed and round section spokes for different wheels and always like having good information for making build decisions.

Any feedback is appreciated, either from an anecdotal or engineering/materials perspective. Thanks!

 

[Circlip]

Replying to my own post here, but to add more information to the discussion, it's worth noting that Sapim's web site lists the "strength on middle section" of the CX-Rays as 1600N/mm^2, compared to the Laser at 1500N/mm^2. Is strength relevant to this discussion? Or is that more related to failure, with Young's modulus more important for determining the contribution of spoke selection toward the compliance of a built wheel? I'm not a materials science guy or an engineer of any type, and admittedly don't know enough about either to understand if they are relevant to the topic.

 

[trulede]

Its complete nonsense. The data sheets from Sapim offer perfect explanation of when to use each spoke. If you are an amature wheel builder, bladed spokes are easiest to deal with.

Here, have a read of this : Nox Composites

In short

So the tire deformation provides more than 100 TIMES the vertical compliance than that of the wheel, whether it is aluminum or carbon.

 

[kiotae]

The above piece from Nox is great. I agree with trulede, the benefits of bladed spokes on a mtn bike is pretty much entirely down to them being easier to build with (all else being equal). There may be some argument in one way or the other in regards to how they deal with stuff getting jammed in there and/or impacts, but I'd imagine that there are too many variables there to really form much of a conclusion.

The other user is whack. If there's any difference (and I don't believe there is), it's so small that all the other "noise" drowns it out entirely.

 

[mikesee]

You can define it any way you like.

Bottom line is that CX-Rays ride like ass.

If you want compliance, use Berd's.

/thread.

 

[Circlip]

Bottom line is that CX-Rays ride like ass.

If you want compliance, use Berd's.

Great pivot on the topic. Would love to have a set of wheels with Berds one day to see what I think. It's on the bucket list.

Quite a few years ago I had a set of Spinergys with PBO spokes that a friend gave to me. The hubs ate the tiny bearings like nobody's business here in the PNW (which I think explains why the wheels were dumped on me) but I really liked the way they rode, and were the only wheel set I've ever owned which felt quite different. I'd expect wheels built with Berds to take that even further.

At the risk of undoing your attempted /thread Mike, can you throw a bone in here with your thoughts on the practical effect of one steel spoke vs another, specifically CX Rays vs Lasers if possible. You say the CX Rays ride like ass. Is that relative to the Berds, or relative to other steel spokes like the Laser?

 

[*OneSpeed*]

I don't know this, but I would expect the Lasers ride better. A bladed spoke is stiffer and can only flex certain ways under load, a round spoke can flex in any direction. At least this is how I see it in my head.

Realistically it's probably not a huge difference in actual ride quality. Lots of other variables to consider. Tire, rim width, aluminum vs carbon, spoke count/lacing pattern, etc.

 

[Circlip]

A bladed spoke is stiffer and can only flex certain ways under load, a round spoke can flex in any direction. At least this is how I see it in my head.

I was pondering this myself. What's the axis in which a spoke flexes when the wheel structure is deforming under stress? (engineers will have to forgive my layperson's terminology) It seems as if the spoke would actually flex by bowing inward or outward rather than inline with the wheel. If so, this would actually give an advantage to the CX Rays flattened shape for being able to deflect more easily, assuming the blade is oriented correctly.

I agree with you and everyone else that this probably has no practical effect that could ever be noticed by a rider if they were doing a blind comparison, but I'm still interested in the theoretical side.

 

[*OneSpeed*]

I have probably 6-8 wheelsets built with Lasers. They're a killer value for certain types of wheels. I know that my wheels ride better than a lot of my friends.

Especially I9's with those strait pull aluminum spokes. Those wheels ride so harsh. I swapped steel hardtails with a buddy not too long ago. There were 3-4 distinct places where my bike rode better and we both noticed.

Wheels: i9's with aluminum spokes Vs. my Hadley/Spank wheels with either Sapim Race or D-light, I forget. Not sure exactly why but these wheels ride super compliant.
Seatpost: my 210mm dropper has a good amount of flex because it's so long.
Handlebars: his cheap aluminum bars Vs. my carbon Oneup bars. Night and day difference
Frame: his steel hardtail was noticeably stiffer than my Kona Honzo St.

All in all it was very noticeable. He immediately bought carbon bars, and later a new steel frame.

 

[rapsac]

Just de-tension (the spokes of) your wheel partially and flex it how you like it...
Then you will see that the manner in which these spokes contribute (in any significant way) to the wheels’ stiffness is not by their own bending stiffness, but rather by their axial stiffness. For the latter property, the cross-sectional shape is not relevant, the cross-sectional area is though, as is the modulus of elasticity, a property defined by the spoke material used.

 

[mikesee]

Just de-tension (the spokes of) your wheel partially and flex it how you like it...

I really hope this is tongue in cheek.

 

[mikesee]

can you throw a bone in here with your thoughts on the practical effect of one steel spoke vs another, specifically CX Rays vs Lasers if possible. You say the CX Rays ride like ass. Is that relative to the Berds, or relative to other steel spokes like the Laser?

I'm a DT Swiss guy for many reasons. So my experiences are with their lineup -- Competition, SuperComp, Revolution, and Aerolite primarily.

I can feel differences but I don't purport that they add up to much. Lots of windup when braking when using Aerolite's. Much more resilient feel to SuperComps.

I arrived at those sensations by building many sets of wheels where the hubs/rims/tires/pressures/spoke tensions and bike stayed the same -- only the spoke gauge changed.

Riding them back to back -- same trails, same bike, same day -- the differences made themselves apparent. This "test" is where I derived my love of SuperComps: they have a certain snap that no other spoke has.

But these differences are small. They basically amount to noise relative to the differences one can arrive at by changing tires or tire pressure, or suspension tuning.

If you want to make a meaningful difference in the feel of your bike, buy quality tires and get a precision gauge to really dial in what you can get away with for low pressures.

 

[Jayem]

My experience echo's Mike's. I've built up a lot of wheels with laser/revolutions. I've built up a lot of other wheels with other spokes, but the ones with the lasers/revos never seemed overly harsh, regardless of the rim material. I think Nox pushes towards their two options because the cx-rays make them more money, so d-light and lasers are mysteriously absent...

 

[FJSnoozer]

I really hate my cx rays. I am also starting to have issues with them snapping near the hub where they transition from bladed to round after about 6 months and 2000 miles.


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[mikesee]

I really hate my cx rays. I am also starting to have issues with them snapping near the hub where they transition from bladed to round after about 6 months and 2000 miles.

I stopped building with them years ago because of this exact phenomenon. No matter how perfectly balanced the tension, no matter the rim material or really even how they were ridden, they were just brittle and would fail apropos of nothing.

Not with everyone, but you could never say who would have problems and who wouldn't, and that's no way to keep customers happy.

 

[sam-eye-am]

Replying to my own post here, but to add more information to the discussion, it's worth noting that Sapim's web site lists the "strength on middle section" of the CX-Rays as 1600N/mm^2, compared to the Laser at 1500N/mm^2. Is strength relevant to this discussion? Or is that more related to failure, with Young's modulus more important for determining the contribution of spoke selection toward the compliance of a built wheel? I'm not a materials science guy or an engineer of any type, and admittedly don't know enough about either to understand if they are relevant to the topic.

Reason the CXrays have a higher tensile strength is the work hardening done by forming the blade. It is relevant to the discussion in how the difference came about, but not relevant unless talking tensile loading at or near the yield strength.

Generally, the stronger you make steel, the more brittle (or less ductile) you make it. Meaning it deforms less as you load it up to failure. Especially when work hardening. The laser may plasticly deform (permanently change length and cross section) where the CX ray will fracture with competitively less plastic deformation at the fracture location.

Young’s modulus is a material characteristic. If the forming process only changes dimension of the spoke in directions perpendicular to the spoke axis, one could conclude that cross sectional areas of the laser and x-ray are the same. Hell, in reality one could conclude they are similar enough that a rider won’t know the difference. Young’s modulus will tell you how much the spoke will grow in length given how much load you put on it and what it’s cross section is. So, in the case of cxray or laser, the change in lengthy for a given load should be fairly equal assuming loads are purely axial or identical if not purely axial.

I’d say that Young’s modulus is really what one is referring to when talking compliance. Without getting into geometrical differences in applied loads for a 3x pattern, how much a spoke changes length in either spoke should be immeasurable.


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[mtnbkrmike]

Warning - super slight momentary thread jack

If only 2 choices - both Sapim - CX-Ray and Race, I'm thinking by the sounds of it that Race may be preferred by the guys in the know, for less money, despite the slight weight increase. Is this correct?

Thanks OP. Back to the topic at hand...

 

[davec113]

There are lots of differences in material properties when steel is work hardened and changed in shape. Young's modulus tends to stay very close to the same, which describes force vs elongation, but so many other things are different. As far as shape, the forces required to bend a beam are in proportion to the distance from the center of the beam to the 4th power, the property is called moment of inertia, and that of a bladed spoke across it's width is going to be MUCH higher vs round, and less in the other axis. Long story short, it's complex and the materials the spokes are make out of and their material properties do in fact matter to the way the wheels feel on the trail.

For me, I use CX-Ray because I tend to break spokes and CX-Rays don't break. They do have an improved fatigue life vs Lasers, so those breaking them routinely may have some other issues as this isn't normal ime. Perhaps the way the wheels were built weakened them by allowing too much deformation, which can easily compromise metal, especially more brittle metal after it's work hardened like CX-Rays. I've used CX-Rays in several wheels with no issues at all, and had many issue with pretty much every other rear wheel I've owned.

That said I would not use them for carbon wheels, I'd use Lasers because they are more compliant. But I don't use carbon rims, I've had a few and I'm fine with DT Swiss aluminum rims.

One of the reasons the Lasers are more compliant is they require less tension, it's really as simple as that. You can build wheels with a range of tensions and CX-Rays are ideally built with a bit more vs Lasers. DH guys are intentionally de-tensioning their wheels to provide the feel they want, of course they can get them rebuilt every few runs, but it shows that this really matters too.

BTW, one of my friends said the DT 1501 wheelset that uses DT bladed spokes w/ XM481 rims was the best wheels he's ever used on his 150mm bike, and he's a FAST pro. So YMMV as far as your preferences and results. People ride different and have different preferences.

 

[davec113]

Here's an example of how Young's modulus doesn't tell the whole story.

A Berd spoke is 1.8mm and Young's for Dyneema = ~125 Gpa

A Laser spoke is 1.5mm and Young's for steel = ~200 Gpa

These spokes have roughly identical force vs elongation curves given this information yet I hear they ride differently. How is that possible!?!?

 

[WHALENARD]

I really hate my cx rays. I am also starting to have issues with them snapping near the hub where they transition from bladed to round after about 6 months and 2000 miles.


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I experienced just this. I rebuild with supercomps...not because I had Mikesee's breadth of experience or anything but simply because that's what I built my last carbon build with and they remain flawless. The difference in feedback through the handlebars on high frequency chatter was immediately noticeable to me.

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