Contact with Mavic Experience or ERD Knowledge
 

Hello, I have Mavic Open Ceramic 28 hole rims laced to Campagnolo Record low-flage hubs. After all these years, ceramic is giving out in spots and I want to replace with all "silver" Mavic rims with same IRD so I can re-use spokes. (I'm... uh... "frugal"). Spokes are DT rear and Alpina Aero front. Does anyone here know what might be an exact (same vintage) "silver" Mavic swap diameter-wise? 28 hole. Or, has anyone been successful in contacting Mavic directly with this type of question? Thanks!!

Sorry, thank you for the correction. I thought IRD was Inside Rim Diameter. But it seems you knew what I intended to say.

I imagine that silver 28h Open Pro rims are at this point rather "thin on the ground" so to speak.
32h was by far the most common drilling.
28h rims from all brands are not too common (not rare, but a small minority of total production offered by most rim makers).

Any vintage-profile rim will require longer spokes than any Mavic Open rim.

Both Spocalc 2022 (link) and FreeSpoke (link) databases list an ERD = 605mm for Mavic Open Pro.

But, as per SurferRosa, trust but verify since you have the rims in hand.

Keep in mind too, if replacement rims are slightly different ERD you might be able to compensate by changing spoke lacing pattern and still re-use same length spokes. Example might be going from 3x spoke pattern to 2x for rims of slightly larger ERD.