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Reading a review of a bike trailer one of the commentators noted that the wheels were laced radially:

enter image description here

It is a 16" wheel. Does this configuration have some advantage making it a good choice? I always had the impression that wheel spokes were crossed for greater robustness.

Cynically I suspect this could just be a way to make the wheels a little cheaper - but cheaper doesn't necessarily mean inferior, or does it in this case?

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  • Does this trailer have rim brakes? Probably not, but its possible.
    – Criggie
    Mar 21 '20 at 23:35
  • It’s stronger, lighter and cheaper. You only need crossed spokes to transmit torque (i.e. rear wheels or disc brakes).
    – Michael
    Mar 22 '20 at 6:46
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Crossed spoke lacing is primarily necessary to transmit torque from the hub to the rim, rather than for increased strength, although I suspect hub flanges have more strength when loaded by a crossed spoke. Given a trailer wheel will carry a lower load than a bicycle wheel this does not matter.

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  • 4
    Torques would be from pedaling or braking... trailer has neither, is that what you mean? Mar 21 '20 at 14:08
  • 3
    Yes, pedaling, disc or drum brakes. Obviously rum brakes operate on the rim. Mar 21 '20 at 15:06
  • Got it. So then in this case, radial is probably just cheaper to make? Mar 21 '20 at 16:14
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    @ArgentiApparatus - Where can I get some of these rum brakes??? Mar 21 '20 at 17:29
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    While the magnitude of this effect is totally irrelevant to trailer wheels, it should be noted that cross lacing requires slightly longer spokes, which does decrease lateral stiffness slightly. So, no torque = radial spokes are slightly better, torque transmitted = cross lacing is a must. Mar 21 '20 at 17:59
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A consideration is the diameter of the wheel, compared to the hub diameter. The smaller the wheel, the more difficult it is to "cross" the spokes.

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    I'd say, it's the angle at the rim that makes cross lacing difficult. And that angle depends on a) the rim's diameter, b) the hub's diameter, and c) the number of crossings relative to the number of spokes. With the tiny hub in the picture, it should be rather trivial to cross the spokes twice. However: What's the point if there's no torque to transmit? Mar 21 '20 at 17:55
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    @cmaster-reinstatemonica a crossed lacing pattern is supposed to be stiffer than a radial pattern, due to the additional crossing points acting as supports for each spoke. A trailer wheel is always vertical so there are lateral forces when cornering, that are different to a bike wheel that leans, so its slightly like a car wheel in that regard.
    – Criggie
    Mar 21 '20 at 23:38
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Radial is cheaper, simpler, and perhaps lighter.

I think that hub flanges are stronger when spokes are laced with some cross. I also think the spokes stay tight better, and it looks better, so my preference is to lace with some cross even in case of front rim brake wheels or trailer wheels. But the default answer is it doesn't really matter for those types of wheels.

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    Why do you think so?
    – ojs
    Mar 21 '20 at 17:34
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    Another point - radial has a visual appeal and is noticeably different to a crossed lacing pattern. Whether its prettier or not, "different" can help a product stand out at the shop/catalogue/website. Doesn't mean its better for the user, just for sales.
    – Criggie
    Mar 21 '20 at 23:40
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    Radial is cheaper, because radial is handily the simplest pattern to lace, fastest to lace, and easiest to teach somebody to lace. This is probably the biggest benefit. Hub flanges are stronger when spokes are laced tangentially; this is common sense and my own experience, and some mfgs. don't spec their hubs for radial nor warranty them if they are laced radial. Spoke loosening is debatable, but I think tangential nipples stay tight slightly better due to the slight torque. For trailers it doesn't matter. I'm guilty of choosing lacing pattern based on the spoke lengths I have in my drawer. Mar 22 '20 at 18:47

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