Honestly, an intensive OT and PT program using horseback riding, among other things, was what made the difference for my son, who has very similar challenges, and who also didn't learn to ride a bike until age 11. He'd been trying to learn since he was 4, so it wasn't an effort or motivation issue. After about six months of daily horseback riding, he suddenly learned to ride a bike and swim, when he had previously struggled terribly with both skills.