I have the opportunity to buy 2 front Shimano Dura Ace C40 latest generation wheels at a very cheap price. The hole count for the wheelset is 16/21. Could I build / have built a rear wheel from one of the front rims, for example using a 32 hole rear hub or is 16 hole too fragile for a carbon rear rim?
I don't have the hub yet, but from research I assume this is the most equilibrated option, correct? With these, do you think I would need new spokes or can I reuse the ones which come with the 16 hole hub? One of the patterns I saw could work, it doesn't require any crossing. Maybe the rear hub could interfere a bit though? The video corresponding to the screenshots supposedly is a professional wheel-builder as he was a making a project for a 16 hole rear wheel, tough steel / aluminium one.
There is also a review from CyclingTips comparing the new generation wheelsets with the old ones. There is a part where they say only the rear tubular version rim is asymmetric.