I'm in a similar boat with my ds7.5 / 2e too with bike riding. He was born with dyspraxia and a host of gross/fine motor issues. He's real pipsqueak though so he's still riding the small bike with training wheels, which I plan to give to my niece who's 3.5 yrs old and not 2e asap.

My ds7.5 told me today that he doesn't want try things because he feels failing. Great. Thanks for the confirmation, but you still have to do therapy buddy, sorry.

Riding a bike and swimming are fantastic exercises to use both sides of the brain and body evenly. Great bilateral work, not to mention the balance and coordination needed.