Originally Posted by
joejack951
Assuming which rim? I can see how a change in roundness would affect tension but I'm skeptical that any decent rim would see that big of a displacement along the bottom (especially given that there is a tire/tube distributing the load).
The spokes at the top must also see an increase in tension from the applied load. The rim losing it's round shape near the bottom should mostly affect those spokes near the deformed area.
The primary displacement of the rim is at the bottom, where it contacts the tire which contacts the ground. No matter the rim, this happens, though it's very small (rim strength obviously controls the amount of displacement). The rest of the rim will sort of 'warp' but much less so than at the bottom. The lower spokes take the most of the load. The other spokes change in tension due to the 'warping'. I really can't explain it that well but Brandt has good drawings of the displaced shape of a rim due to all sorts of loading.