Here is another option: use a 'run bike' to help your child learn balance. This makes it easier to know when they are ready.
A run bike (aka 'balance bike') is essentially a bicycle with no pedals. There is a good New York Times article about balance bikes. Unlike a tricycle, a balance bike teaches balance, which is really the limiting factor for children learning how to ride.
Once they can cruise around on a balance bike, it will be easy to see when they are ready for pedals. My son started walking his around at the age of 2, and can now run with it (at 2.25 yrs and warm weather), although he hasn't gotten the balance part yet.
There are some good questions and answers over at bicycles.stackexchange.com that include a discussion of different methods that can be used to teach a child to ride a bike.
- What is the best method to teach a young child to ride?
- Is a “run-bike” equivalent to a bmx bike with no drivetrain?
