to ride/riding

[wowenglish1]

I would like to know which sentence(s) is/are correct.
1. It is fun to ride a bike.
2. It is fun riding a bike.
3. To ride a bike is fun.
4. Riding a bike is fun.

[mamen]

Originally Posted by wowenglish1

I would like to know which sentence(s) is/are correct.
1. It is fun to ride on a bike.
2. It is fun riding a bike.
3. To ride on a bike is fun.
4. Riding a bike is fun.

All sound grammatical to me now.

(not a teacher)