You know, I wouldn't know where to begin teaching an adult to ride a bike.
The idea is so inconceivable to me that someone never rode a bike when they were a little kid!
Yes -- I was shocked when I realized that she had never been "indoctrinated"!!
(I was already married and moved out before she was born so I just assumed I just missed it!)
Teddy has given some great ideas... a soft surface (but grass not too long or its too hard to get wheels going)... make sure she can reach ground easily... and I am wondering why not walk beside, run behind her and hold bike while she gets the balance thing down?
Well -- since we are the same size, I'm kinda afraid we'd both end up in a heap if she really lost her balance with me running beside her "helping." Plus, as Mimi alluded to, this part of the process was horrible for me, but then I was a HUGE chicken as a kid!!!
Good luck and kudos to you for getting her on a bike
