We've had Owen and Eli for the past week or so while their parents could take a vacation for their 20th anniversary. The boys spent the first few days at the other grandparents. While they were here, they wore us out. Eli, being 12, has passed grandma in height. He's also starting to morph into a jerk and I see a serious attitude adjustment on the horizon.
That bit out of the way, neither of the boys can ride a bicycle. Bikes have been a major part of my life since I was 4 years old. I even raced in France once. I sucked, but hey, I raced in France. My kids went on overnight bike camping trips with me. The boys Mom even did a two day, two hundred mile trip with me. Eli flat out refuses to ride and won't give a reason. Owen, on the other hand, says he is afraid of falling and getting hurt.
Today, grandma talked Owen into going for a ride with me on the back of our tandem bike. She told him that he could hold it over Eli's head that he rode and Eli didn't. Owen was quite a bit nervous when we started. I'm a bit shaky on it with that initial start, so I'm sure that didn't help. Anyway we rode up the short hill from the house, turned around, and coasted back down to the end of the street. I asked him how that was and he said fun. Do it again. We did it again, hitting about 19 mph on the way down the hill. I asked if he wanted to ride a bit further and he said yes. Back up the hill a third time, this time turning right. We got about a half mile down the road when Owen said, "I've never been here before." To which I replied, "If you can ride two wheels, you''ll see lots of places and things you've never seen before." He was quiet for a little bit, then said. "Look! Two big birds in that yard!" He spotted a pair of Sandhill Cranes. I told him he would not have seen them if he'd been in a car. We turned around for home. As we are climbing another hill, Owen says, "Grandpa, my balls hurt."

Nice guy that I am, I told him he shouldn't sit on his balls.
We got back to Chez Fromage and he ratchet jawed to grandma about how much fun he had, that he saw two big birds, and that he sat on his balls.

We have a 20" Trek bike that he can try to solo on next week. It's old and getting new tires and an overhaul tomorrow.