Interesting analysis of the stresses on a wheel

[sjs]

the only acceleration it feels is the radial centrifugal acceleration away from the hub.

The acceleration is towards the hub. The force exerted by the fly on the tyre is away from the hub.

[Brucey]

Hi Guys & Girls, Very interesting stuff, way above my head & level of maths! But may I throw into the mix the different loads & needs exerted on spokes when used in Tricycle Wheels? R.S.V.P. TTFN MM

trikes see much higher torque loads on the driven wheel if they have low gears and much higher lateral loads on all wheels. Since the model does not appear to have included any externally applied lateral loads (which to my mind means it doesn't represent what is going on in a bicycle wheel, leave alone a tricycle wheel) then it is of questionable relevance to trikes.

...In that analysis, the gains by moving to a radial non-drive side lacing could be gained by increasing the tension of a 3x lacing to match the radial wheels maximum spoke tension which probably wouldn't change the tension range. Removing the drop in non-drive side tension is the reason for a radial lacing but it increases both the maximum tension and the maximum tension range. Tightening the spokes a bit may provide the benefit of radial non-drive side lacing without the costs...

Because of the dishing, there is always going to be a tension difference between the NDS and DS spokes when using standard parts. You can do all kinds of other wacky things (with hub, rim and frame design) to alleviate this but in the absence of these (and even with some of them) the wheel is going to be differently stiff w.r.t. lateral displacements each side (whether direct or induced). Tightening all the spokes will change the way the wheel works a bit, but you can't always do this; rims crack in service or start to buckle via an elastic failure mode.

In the modelling work (and in reality) having fully slack spokes under load is deemed bad mainly because it causes loosening. IME once you subject a wheel to real-world lateral loading, there are few if any standard built/dished lightweight rear wheels where the NDS spokes can't be made to go more or less completely slack at times. Thus to my mind there are only a few solutions; one is to avoid such wheels, and another is to simply use locking compound on the NDS spoke nipples.

I kind of wished that they had modelled triplet rear spoking (as per campag and fulcrum wheels). These have more even spoke tensions to start with, but may perhaps also have higher fatigue loading on the NDS spokes than normal.

cheers

[bobc]

Enjoyed that - interesting stuff & thanks to them for publishing.
I WOULD beintersted to see how differing flange diameters might affect conclusions (which IS something their analysis could easily do....)

[bryce]

Also how the peak stresses interact on the hub flange. At the moment, x3 with 2.0-1.8-2.0 drive side and 2.0-1.5-2.0 spokes look like the ideal option for a better rear derailleur wheel with an expensive hub. With the butting there to provide a bit of spring to protect the spoke ends and the hub flange. Though an unbutted machine built wheel survived perfectly well, so this may be over thinking things.