Weird lines on Mavic 217 SUP rims

[JRGSXR]

If you have access to, or can get your hands on a dye penetrant kit. It will give you the definitive answer. Won’t damage the rims or finish either. Only takes 15-20 mins to do.

 

[Woz]

These are definately cracks. Those rims are prone to cracking, especially near the eyelets. I have one NOS rim with exactly the same issue.

- errrrr. Like how is that possible? Surely a NOS rim is in a state of no / hardly any stresses?

Is it like damage from the environmental or a gross design / manufacturing fault.

I'm not sure they are cracks. They look far too precise. I suspect shop wear / storage marks from ceiling hooks / roof racks / wall racks.

The valve hole shows corrosion though.

 

[retrobate]

- errrrr. Like how is that possible? Surely a NOS rim is in a state of no / hardly any stresses?

Is it like damage from the environmental or a gross design / manufacturing fault.

I'm not sure they are cracks. They look far too precise. I suspect shop wear / storage marks from ceiling hooks / roof racks / wall racks.

The valve hole shows corrosion though.

Internal stress from the extrusion process (probably minimal) and then being rolled into a ring (more significant) combined with age hardening.
Spoke hole drilling (especially if the tool was worn) and eyelet insertion could be a propagation point and also cause stress.
The marks would be running along the grain structure of the extrusion.
If there is corrosion around the valve hole corrosion under the eyelets could also be an exacerbating factor.

So I could believe that they are cracks but personally would not want to say that they definately are just from the photos.

 

[bikeworkshop]

One decent ride would tell you surely