Hello. I was wondering about the possibility of tuning my mavic CCU hubs to basically change freehub system to a Tune-like one, use bigger bearings and make a carbon 1 piece axle instead of the actual 2-piece one.

Any hints/opinions?

Thanks very much!

Anything is possible if you have the Engineering talent / deep enough pockets. I don't see why it would not be possible to change things. But the question you have to ask is what you would gain, and whether it wouldn't be easier to buy some lightweights or commission lightweight to do a special hub for you. I see 3 options:

1) Easy
The bad side of the current hubs is that they are a bit heavy and use a bushing not a bearing. If you were to add the ebay bearing mods to a Mavic titanium freehub you would get a slightly nicer hub for something like $250. I don't think a carbon axle would be worthwhile because it loses a lot of the flexibility in return for no real gain.

2) Hard
Another possibility might be to machine out the hub a bitt to take a DT type ratchet and totally new internals and an aluminium freehub. But that would take a lot of skill, alongside a very large and expensive machining centre to fit the whole built up wheel in

3) Harder
I think the wheels are built by lacing up the carbon spoke flanges and then popping the hub in. If you worked out a way to de-bond or cut out the hub centre, you could add a custom hub. But if you could do that then you are 50% of the way to building your own wheels.