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

 

[Uncle Grumpy]

I am about to buy a nice set of wheels with Mavic 217 SUP Ceramic rims.

Based on the comments here and my own experience of 217s, you are buying hubs, spokes and nipples.

Depending on price - that might not be a bad deal, lace them across to another pair of Mavics that aren't 217s.

Grumps

 

[Nabeaquam]

Based on the comments here and my own experience of 217s, you are buying hubs, spokes and nipples.

Depending on price - that might not be a bad deal, lace them across to another pair of Mavics that aren't 217s.

Grumps

Make sure to face the rims so the offset angle on the spoke holes are the same on both rims, not like I did in the above example. I ride it like this, good enough, perfect.

 

[Retrorockit]

I could see the hard coating cracking while the ductile Aluminum (Aluminium?) under neath could be OK. It looks to me like it was drilled out for a Schrader valve. That would concern me on a narrow rim. Tire inflaton pressure, and brake application forces could flex it in that direction, cracking the hard ano but just flexing the metal normally. No way for me to be sure from here.

 

[MMaister]

Thank you everyone for your reply. I told the owner to do some NDT like penetrating dye to check if these are cracks or not. I will let you know if there will be any results.

 

[Retrorockit]

If the metal was failing I would expect the crack to open up, and get wider over time. The fact that they are closing up all the way makes me think it could be just the coating not being able to move flexibly with the metal.