Get your pals to phone up to arrange a bike ride at a predetermined time, let your wife answer the phone, when your mate asks "Just phoning to see if Bushwacked is coming out for a ride on Saturday", it's much harder for her to say no.
I did try the "Just tell her" strategy but that is more high risk……….
As a medium term strategy make sure you encourage the kids to get into cycling – it's a lot easier to get permision to go to some trail centres because Sprog has been pestering all week. Then you will face the next problem of net being able to keep up with them…………