It would be worth putting in the effort to learn to ride a bike (I fell down enough on my two feet as a kid, let alone two wheels!) just to use one of these things!
http://www.dannychoo.com/en/post/26963/Japan+Underground+Bicycle+Parking+Systems.html
http://www.dannychoo.com/en/post/26963/Japan+Underground+Bicycle+Parking+Systems.html