To cut a long story short , Im buying some Flow EX’s from a mate for my Orange Crush. The front is 15mm Maxle so a direct swap for my Mavic 319’s . The rear of mine is q/r and the flows have 12mm so thats simple enough just get some superstar reducers . the problem is a friend wants to buy my mavic 319’s to replace his semi fat wheels on his beast of the east. his current rear wheel is 142 x 12 and mine is 9mm quick release.
Can this be adapted.? Thanks for your help.

We need to know what make the hub is ?

Shimano 575’s mate.