not being able to swim? It seems lots of people say "He can't ride a bike or swim", or "I never learned how to ride a bike. I can't swim either". I can do both but I am a lot better of swimmer than cyclist. I took my first swimming lessons at the pretty much the youngest age our city allows us to and all the way up to grade 5. I didn't learn how to read a bike until I was 11. I basically learned the two skills 10 years apart. If it weren't for peer pressure, (not direct peer pressure, but the type where everyone is doing something so you think you have to do it) I probably would never have learned to ride a bike. I was kind of embarrassed when I did learn because my parents would tell people in the park that I "just learned to ride a bike" if I made a mistake because I was so old (and I looked even older, more like 13 as I was tall). However, I would probably still know how to swim because I was put in swimming lessons by parents at a very young age, unlike with bike lessons.
So why is it that if someone doesn't know how to ride a bike, they often don't know how to swim either. I know 2 people who can't really ride a bike and both of them can't swim either. However, up until 6 years ago, I didn't know how to ride a bike, but I knew how to swim.