Interesting analysis on spke patterns and stiffness!

[Chewyeti]

In this report, there is a ton of data and experiments done to show the impact of lacing patterns on spoke strains and lateral rigidity.



here is the conclusion for ya if you choose to skip the nitty gritty.

CONCLUSIONS
Requirements of strength, stiffness, and low weight are satisfied in bicycle wheels by combining
a light-weight rigid rim with pre-tensioned wire spokes. In many rear wheels very high pre-tension
stresses in half the spokes are required to maintain an asymmetrical shape. The radial, lateral, and tangential
stiffness of wheels with various spoke sizes, spoke geometries and rim stiffnesses is presented.
The behavior of bicycle wheels subjected to static radial loads can be accurately modeled by idealizing
the system of interlacing spokes as a linear elastic foundation of uniform stiffness per length of circumference.
The spoke pattern affects the over-all radial stiffness of the wheel more than it affects the spoke
strains. From a theoretical analysis, a numerical analysis, static experimental analysis, and in-service
measurements, the spoke strains appear to be insensitive to the pattern of the spoke lacing. From a
numerical analysis, the spoking pattern has the greatest impact on the spoke strains when the wheel is
subjected to large lateral loads, such as during cornering. In this case, wheels with longer spokes have
lower strains than do wheels with shorter spokes. Small variations in measured spoke strains between
the wheel types under actual riding conditions, are attributed to variations in un-measured loads. The
extreme spoke stress cycles in the road test experiments were on the order of 150 MPa. Each cycle at
this stress level shortens the remaining fatigue life by one one-millionth of the total fatigue life. Larger
stress cycles, due to large lateral loads, for instance, could shorten the fatigue life considerably. Future
work could therefore be directed toward:
 Measurements of spoke strains due to high lateral loads, and,
 Non-linear modeling of spoked wheels subjected to spoke-slackening loads.
The fatigue resistance of the spokes, the spoke diameter, the arrangement of the spokes, and the
stiffness of the rim influence wheel stiffness and fatigue life. Wheels with 2X, 3X, and 4X spoke
patterns all have similar spoke strains when subjected to radial loads. The fatigue resistance of spoked
wheels to steady cycling loads is very high for most typical service conditions.