My DH is the same way. If I try to talk about something that bothers me, he thinks it's an attack, gets defensive and it becomes a fight. He used to be the mellow one and I had the temper, but we're changing and now it's opposite (him hating his job but not wanting to look for something else has a lot to do with it).

Anyway, I don't know what to say to help you out. I know you have to tread lightly and not make him upset. Maybe you could sit him down and tell him it's about YOU not him. YOU want to ride your bike more because of the great feeling you get. YOU want to go on longer rides and take the kids to get them out and about and keep them in good health. YOU would love to have his company because you love him and want to enjoy time together.
If you use lots of ME/I statements maybe he won't get defensive????

Let us know what happens.